Buderus Buderus Logamax plus GB172/GB172T TECHNICAL GUIDE (2011/06)

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Page 1

Technical Guide Issue 2011/06

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Logamax plus GB172/GB172T

Heat is our element

Wall mounted gas condensing boiler

Power range from 2.9 kW to 24 kW

Page 2

Table of contents

1 Logamax plus GB172/GB172 T

gas condensing boiler . . . . . . . . . . . . . . . . . . . 4

1.1 Logamax plus GB172/GB172 T

characteristics and applications . . . . . . . . . 4

1.2 Overview of boiler types

Logamax plus GB172 . . . . . . . . . . . . . . . . . 6

2 Technical description . . . . . . . . . . . . . . . . . . . . . 8

2.1 Logamax plus GB172/GB172T

equipment level . . . . . . . . . . . . . . . . . . . . . . 8

2.2 Logamax plus GB172/GB172T

function principle . . . . . . . . . . . . . . . . . . . . 12

2.3 Logamax plus GB172/GB172T

dimensions and specification . . . . . . . . . . 17

2.4 Dimensions and specification

of DHW cylinders . . . . . . . . . . . . . . . . . . . 29

2.5 Installation dimensions

Logamax plus GB172 . . . . . . . . . . . . . . . . 37

3 Regulations and operating conditions . . . . . 42

3.1 Extracts from the regulations . . . . . . . . . . . 42

3.2 Operating requirements . . . . . . . . . . . . . . . 42

4 Heating controls . . . . . . . . . . . . . . . . . . . . . . . . 43

4.1 Aims of the Logamatic control system . . . 43

4.2 Logamatic EMS control concept . . . . . . . 43

4.3 Types of controls . . . . . . . . . . . . . . . . . . . . 44

4.4 Boiler and control components in the

Logamatic EMS control system . . . . . . . . 45

4.5 Function modules for extending the

Logamatic EMS control system . . . . . . . . 49

4.6 Selection aid for possible equipment levels using the components of the

Logamatic EMS control system . . . . . . . . 53

4.7 Logamatic 4121 and 4122 control units . 54

5 DHW heating . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

5.1 Selection aids for selecting integral or

separate DHW heating . . . . . . . . . . . . . . . 57

5.2 Application limits Stratification cylinder with the GB172-20 T100S, GB172-14/24 T150S and

GB172-14/20 T210SR . . . . . . . . . . . . . . 58

5.3 Integral DHW heating with a plate heat exchanger in the

Logamax plus GB172-24 K . . . . . . . . . . . 58

5.4 Selection of a suitable DHW cylinder . . . . 59

5.5 DHW circulation line for DHW cylinder . . 60

6 System examples . . . . . . . . . . . . . . . . . . . . . . . 61

6.1 Information regarding all

system examples . . . . . . . . . . . . . . . . . . . . 61

6.2 Important hydraulic system components . 66

6.3 Boiler hydraulics for appliances

with integral DHW heating . . . . . . . . . . . . 72

6.4 Boiler hydraulics for appliances

with separate DHW heating . . . . . . . . . . . 82

7 Condensate drain . . . . . . . . . . . . . . . . . . . . . . . 94

7.1 Condensate drain from the gas

condensing boiler and the flue . . . . . . . . . 95

7.2 Condensate drain from a

moisture-resistant chimney . . . . . . . . . . . . 95

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

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Table of contents

8 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

8.1 Selection aid for connection

accessories Logamax plus GB172 . . . . . . 96

8.2 Selection aid for pre-installation unit Logamax plus GB172 and GB172-24 K –

not applicable for GB172-24 T50 . . . . . 103

8.3 Selection aid for connection

accessories Logamax plus GB172T . . . . 104

8.4 Heating circuit quick installation

systems . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

8.5 Heat exchanger recognition set

for gas condensing boilers . . . . . . . . . . . . 115

8.6 Transferable output of the heating

circuit quick installation sets . . . . . . . . . . 118

8.7 Heat meter set . . . . . . . . . . . . . . . . . . . . . 118

9 Flue systems for open flue operation . . . . 119

9.1 General information for open flue

operation . . . . . . . . . . . . . . . . . . . . . . . . . . 119

9.2 Flue gas routed through a flue inside a shaft with GA set and secondary

ventilation . . . . . . . . . . . . . . . . . . . . . . . . . . 124

9.3 Concentric air/flue gas routing in open flue operation with GA-X set in conjunction with GA-K or LAS-K set

(LAS multiple connection) . . . . . . . . . . . . 126

9.4 Routing flue gas via flexible flues inside a shaft with the ÜB-Flex set in conjunction with the GA set

or with the GA-X and GA-K sets . . . . . . . 128

9.5 Routing the flue gas via a moisture-resistant chimney with set GN . 130

10 Flue systems for balanced

flue operation . . . . . . . . . . . . . . . . . . . . . . . . . 132

10.1 General information for balanced flue

operation . . . . . . . . . . . . . . . . . . . . . . . . . . 132

10.2 Vertical, concentric air/flue gas routing

above the roof with the DO set . . . . . . . . 137

10.3 Air/flue gas routing via concentric pipe

inside a shaft with DO-S set . . . . . . . . . . . 140

10.4 Concentric air/flue gas routing through

a flue and shaft with GA-K set . . . . . . . . . 143

10.5 Concentric air/flue gas routing through a flexible flue and shaft with ÜB-Flex set

in conjunction with the GA-K set . . . . . . .145

10.6 Concentric air/flue gas routing

on an external wall with GAF-K set . . . . . 147

10.7 Concentric air/flue gas routing via a separate combustion air line inside the installation room and via a flue with secondary ventilation

in a shaft with GAL-K set . . . . . . . . . . . . .150

10.8 Concentric air/flue gas routing for multiple boiler connections

under positive pressure operation . . . . . . 152

10.9 Concentric air/flue gas routing via an

air/flue gas system with LAS-K set . . . . .155

11 Individual components for flue systems . . 157

11.1 Components for individual appliances,

internal diameter Ø 80 mm . . . . . . . . . . . . 157

11.2 Components for individual appliances,

internal diameter Ø 125 mm . . . . . . . . . .158

11.3 Air/flue gas lines for individual appliances,

internal diameter Ø 80/125 mm . . . . . . .159

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

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1 Logamax plus GB172/GB172 T gas condensing boiler

1.1 Logamax plus GB172/GB172 T characteristics and applications

1.1.1 Special features

Benefits Key features

Gas condensing compact heating centre

GB172-14 T120, GB172-14/20 T150,

Gas condensing boiler

GB172-14/20/24, GB172-24 K, GB172-24 T50

Preferred application range

Preferred installation site

Output • Models with the following outputs:

Emissions • Emissions performance better than the limits set by the “Blue Angel” certificate of environmental excellence Standard efficiency • High standard seasonal efficiency [to DIN] of up to 109 % Economic viability • Very low power consumption Hydraulic system • Easy hydraulic connection

Easy installation • All assemblies and electrical terminals accessible from the front Quick installation,

commissioning and maintenance

Compatible connections for wall mounted appliances

Equipment (comprehensive equipment level)

• Detached houses, two-family homes and terraced houses

• Buildings with low heat demand

• Floors and living areas

• In basements or on the same floor

• Below the roof

– 14 kW, 20 kW and 24 kW as condensing boilers – 24 kW as condensing combi boiler – 24 kW compact condensing boiler with integral 48 l

DHW cylinder

• Output modulates between 21 % and 100 % (on the 14 kW appliance)

• Suitable for standard hydraulic solutions

• Reduced installation and maintenance effort

• Straight-forward replacement of older appliances by compatibility of hydraulic connections (connections identical with the Logamax U appliances and Logamax plus GB112 Linea, GB122, GB132, GB152)

• With universal flue sets

• Simplified commissioning and service through the service menu of the RC35 programming unit

• With universal connection accessories for Logalux WU120 W, WU160 W, H65 W, S120 W and SU...W DHW cylinders (flexible hoses) and flue sets

• Water and gas connections compatible with Junkers appliances without adaptor set

• Water and gas connections compatible with Vaillant appliances with adaptor set (accessory)

• Including drain & fill valve, safety valve and 3-way valve

•Expansion vessel – Accessories; may be integrated on GB172

condensing boilers as an option (12 l)

– Factory-fitted on the GB172-24 K combi boiler

(12 l)

– Factory-fitted on the GB172 T50 compact

appliance (12 l)

Table 1 Logamax plus GB172/GB172T characteristics and special key features

GB172-20 T100S, GB172-14/24 T150S,

GB172-14/20 T210SR

• Detached houses, two-family homes and terraced houses

• Buildings with low heat demand

• Floors and living areas

• In the basement

• Inside the living area

• Below the roof

• Models with the following outputs: – 14 kW, 20 kW and 24 kW as compact

condensing heating centre with integral DHW cylinder

• Output modulates between 21 % and 100 % (on the 14 kW appliance)

• Reduced installation and maintenance effort

• With universal flue sets

• Simplified commissioning and service through the service menu of the RC35 programming unit

• With connection accessories for optional connection on the left, right, top or back

–

• Including drain & fill valve, safety valve and 3-way valve

•Expansion vessel

Part of the standard delivery for the GB172-14

–

T120, GB172-14/20 T150, GB172-20 T100S, GB172-14/24 T150S (18 l).

–

Part of the standard delivery for the GB172-14/20 T210SR (12 l)

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 5

Benefits Key features

Gas condensing compact heating centre

GB172-14 T120, GB172-14/20 T150,

Gas condensing boiler

GB172-14/20/24, GB172-24 K, GB172-24 T50

DHW heating • Logamax plus GB172-14/20/24 may be combined

with a separate DHW cylinder Logalux WU120 W, WU160 W, H65 W, S120 W, SU160 W, SU200 W and SU300 W

• Logamax plus GB172-24 K and GB172-24 T50 with integral DHW heating; 30 kW booster function for DHW

• GB172-24 K: rapid DHW heating with regulated DHW outlet temperature

• GB172-24 T50 with integral 48 l internal indirect coil DHW cylinder for convenient DHW heating in locations where space is restricted

Heat exchanger • Integral cast aluminium-silicon heat exchanger Burner • Stainless steel linear radiant burner as premix gas burner for the cleanest combustion

GB172-20 T100S, GB172-14/24 T150S,

GB172-14/20 T210SR

• GB172-14 T120, GB172-14/20 T150: compact heating centre with internal indirect coil DHW cylinder

• GB172-20 T100S, GB172-14/24 T150S: compact heating centre with stratification cylinder

• GB172-14/20 T210SR: compact heating centre with dual mode stratification cylinder for solar DHW heating

Table 1 Logamax plus GB172/GB172T characteristics and special key features

1 Logamax plus GB172/GB172 T gas condensing boiler

1.1.2 Selection aid Burner

Brenner Regelgerät

Premix gas

Gas-Vormisch-

burner

brenner

Control unit (accessories)

(Zubehör)

Programming unit

Bedieneinheit RC25/ RC20 RF

Programming unit

Bedieneinheit RC35

Flue system

Abgassystem Warmwasser-

DHW heating

bereitung

none

ohne

open flue

raumluftabhängig

balanced flue

raumluftunabhängig

Multiple connection,

Mehrfachbelegung

balanced flue

raumluftunabhängig

open flue

raumluftabhängig

separate

separat

integrated, 30 kW

integriert, 30 kW

integrated,

integriert,

cylinder with

Rohrwendel-

internal indirect coil

speicher

integrated,

integriert,

stratified charge

Schichtladespeicher

cylinder

integrated, dual mode

integriert, bivalenter

stratification cylinder

Schichtladespeicher

none

ohne

separate

separat

Models/

Ausführung/

Combination

Kombination

GB172-14 GB172-20 GB172-24

GB172-24 K

GB172-14 T120 GB172-14 T150 GB172-20 T150 GB172-24 T50

GB172-14 T150S GB172-20 T100S GB172-24 T150S

GB172-14 T210SR GB172-20 T210SR

GB172-14 GB172-20 GB172-24

Logamatic 4121

balanced flue

raumluftunabhängig

Multiple connection,

Mehrfachbelegung

balanced flue

raumluftunabhängig

Fig. 1

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

integrated, 30 kW

integriert, 30 kW

integrated,

integriert,

cylinder with

Rohrwendel-

internal indirect coil

speicher

integrated,

integriert,

stratified charge

Schichtladespeicher

cylinder

GB172-24 K

GB172-14 T120 GB172-14 T150 GB172-20 T150 GB172-24 T50

GB172-14 T150S GB172-20 T100S GB172-24 T150S

6720648096-03.1O

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1 Logamax plus GB172/GB172 T gas condensing boiler

1.2 Overview of boiler types Logamax plus GB172

6 720 641 280-01.1il

Fig. 2 Gas condensing boiler Logamax plus

GB172-14/20/24 /K

Key Explanation Logamax plus Umbrella term GB172 Series

-14/-20/-24 Output in kW K Combi boiler (with integral DHW

heating according to the instantaneous water heater principle)

Table 2

6 720 646 236-01.1il

Fig. 3 Gas condensing boiler Logamax plus

GB172-24 T50

Key Explanation Logamax plus Umbrella term GB172 Series

-24 Output in kW T50 With integral 48 l DHW cylinder

Table 3

6 720 648 096-01.1O

Fig. 4 Gas condensing compact heating centre

Logamax plus GB172-14 T120, GB172-14/20 T150, GB172-20 T100S, GB172-14/24 T150S, GB172-14/20 T210SR

Key Explanation Logamax plus Umbrella term GB172 Series

-14/-20/-24 Output in kW T With integral DHW cylinder 100/120/150/210 Approximate capacity of the

DHW cylinder

S Stratification cylinder R Indirect coil for solar DHW

heating

Table 4

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

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1 Logamax plus GB172/GB172 T gas condensing boiler

Logamax plus Rated output Equipped ex works for

in kW

Natural gas E (G20)

Part no.

Natural gas LL (G25)

Part no.

LPG

conversion kit

Part no.

Appliances without DHW cylinder

GB172-14 14 7 716 010 416 7 716 010 613 8 737 600 365 0

GB172-20 20 7 716 010 417 7 716 010 614 8 737 600 366 0

GB172-24 24 7 716 010 418 7 716 010 615 8 737 600 367 0

GB172-24 K 24 7 716 010 415 7 716 010 612 8 737 600 368 0

Appliances with DHW cylinders with internal indirect coil

GB172-24 T50 24 7 716 701 390 7 716 701 406 8 716 764 907 0

GB172-14 T120 14 7 736 615 651 7 736 615 652 8 737 600 337 0

GB172-14 T150 14 7 736 615 653 7 736 615 654 8 737 600 337 0

GB172-20 T150 20 7 736 615 655 7 736 615 656 8 737 600 341 0

Appliances with stratification cylinder

GB172-14 T150S 14 7 736 615 657 7 736 615 658 8 737 600 338 0

GB172-14 T210SR 14 7 736 615 503 7 736 615 504 8 737 600 338 0

GB172-20 T100S 20 7 736 615 661 7 736 615 662 8 737 600 342 0

GB172-20 T210SR 20 7 736 615 505 7 736 615 506 8 737 600 342 0

GB172-24 T150S 24 7 736 615 659 7 736 615 660 8 737 600 340 0

Table 5 Logamax plus GB172 output sizes

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

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2 Technical description

2.1 Logamax plus GB172/GB172T equipment level

1 ON/OFF switch 2 Pressure gauge 3 Logamatic RC35 programming unit 4 Base controller BC25 5 DHW temperature sensor (not shown) (only for

GB172-24 K)

6 Condensate trap 7 DHW plate heat exchanger (only for GB172-24 K)

(not shown)

8 Flue gas temperature limiter (not shown) 9 Test port for gas supply pressure 10 Adjusting screw, gas volume, lowest load 11 Gas restrictor, gas volume adjustment, full load 12 Valve for filling with nitrogen (expansion vessel, only for

GB172-24 K)

13 Suction pipe 14 CH flow 15 Flow temperature sensor (not shown) 16 Expansion vessel (standard equipment only for

GB172-24 K, otherwise accessory)

17 Automatic air vent valve 18 Bracket 19 Type plate (not shown) 20 Test port for flue gas 21 Combustion air inlet 22 Flue pipe 23 Test port for combustion air 24 Inspection aperture 25 Fan 26 Mixing facility with flue gas non-return device (diaphragm) 27 Electrode set (not shown) 28 Temperature limiter for heating block 29 Cast aluminium heat exchanger 30 Ignition transformer 31 Condensate tray 32 Inspection aperture cover 33 Heating circuit pump (not shown) 34 3-way valve (not shown) 35 Turbine (not shown) (only for GB172-24 K) 36 Safety valve heating circuit (not shown) 37 DHW safety valve (not shown) (only for GB172-24 K) 38 Drain & fill valve (not shown)

21 20

17 16 15

14 13 12

6 7

Fig. 5 Assemblies Logamax plus GB172

(example GB172-24 K)

22 23

25 26 27

32 33 34

35 36

6 720 641 280-03.1il

The wall mounted Logamax plus GB172 and GB172-24 K gas condensing boilers have been tested in compliance with the Gas Appliances Directive 90/396/EEC. The requirements of standards EN 483 and EN 677 were taken into consideration. These boilers, with an output of 14 kW, 20 kW and 24 kW, can be operated with natural gas and LPG in accordance with appliance category II

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

2ELL3P

Page 9

2 Technical description

17 16

15 14

13 12

9 8

5 6

6 720 646 236-06.1il

Fig. 6 Logamax plus GB172-24 T50 assemblies

20 23 21

24 26

27 28 29

30 31 32

34 35 36 37

1 ON/OFF switch 2 Pressure gauge 3 Slot for Logamatic RC35 programming unit 4 Base controller BC25 5 Temperature sensor at the cylinder return 6 Safety valve (DHW) 7 Expansion vessel (DHW, 2 litre), accessory 8 Flue gas temperature limiter 9 Test port for gas supply pressure 10 Adjusting screw, gas volume, lowest load 11 Gas restrictor, gas volume adjustment, full load 12 Suction pipe 13 Ignition transformer 14 Expansion vessel (central heating) 15 Valve for charging with nitrogen 16 Automatic air vent valve (not shown) 17 Test port, control pressure (not shown) 18 Test port for flue gas 19 DHW cylinder (not shown) 20 Flue pipe 21 Test port (not shown) 22 Combustion air inlet 23 Test port for combustion air 24 Mixing facility (not shown) with flue gas non-return device

(diaphragm)

25 Clip (not shown) 26 Fan 27 Electrode set (not shown) 28 Temperature limiter for heating block 29 Flow temperature sensor 30 CH heat exchanger 31 Flue pipe 32 Heating flow (not shown) 33 Type plate (not shown) 34 3-way valve (not shown) 35 Heating circuit pump 36 Condensate trap 37 Safety valve (heating circuit)

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

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2 Technical description

19 20

18 21

16 15 14 13 12 11 10

9 8

7 6

23 24 25 26 27 28 29 30 31 32 33 34

2 1

6 720 648 096-19.1O

3 4

1 Base controller BC25 2 Logamatic RC35 programming unit (accessory) 3 Pressure gauge 4 ON/OFF switch 5 DHW cylinder 6 Type plate 7 DHW temperature sensor (not shown) 8 Cylinder primary pump (not shown) 9 Condensate trap 10 Plate heat exchanger 11 Flue gas temperature limiter 12 Test port for gas supply pressure 13 Adjusting screw, gas volume, lowest load 14 Gas restrictor, gas volume adjustment, full load 15 Suction pipe 16 CH flow 17 Automatic air vent valve 18 Test port for flue gas 19 Combustion air inlet 20 Flue pipe 21 Test port for combustion air 22 Fan 23 Mixing facility with flue gas non-return device (diaphragm) 24 Set of electrodes 25 Temperature limiter for heating block 26 Flow temperature sensor (not shown) 27 CH heat exchanger 28 Ignition transformer 29 Condensate tray 30 Inspection aperture cover 31 3-way valve 32 Heating circuit pump 33 Drain & fill valve (DFV) 34 Safety valve (heating circuit) 35 Protective anode 38 Drain tap

Fig. 7 Assemblies Logamax plus GB172 T

(example GB172-20 T100S)

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

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2 Technical description

Boiler block, burner and heat exchanger

• Internal sealed combustion chamber

• Stainless steel premix burner

• Cast aluminium:silicon heat exchanger

• Gas combination valve with adjustable gas appliance

pressure regulator and gas solenoid valves

• Flame monitoring system

• Cyclic ignition via ignition electrode

Hydraulic components

• Integral high efficiency heating circuit pump

(energy efficiency category A) – As an option, either output-dependent or differential

pressure-dependent control for every appliance version of the Logamax plus GB172 range (standard equipment)

• Integral 3-way diverter valve

•Expansion vessel

– May be integrated for the GB172-14/20/24

(accessory)

– Factory-fitted for the GB172-24 K, GB172-24 T50

(12 l): 0.75 bar pre-charge pressure

– Part of the standard delivery for the

GB172-14/20 T210SR (12 l), 0.75 bar pre-charge pressure

– Part of the standard delivery for the

GB172-14 T120, GB172-14/20 T150, GB172-20 T100S, GB172-14/24 T150S (18 l),

1.9 bar pre-charge pressure

• Automatic air vent valve

• Safety valve (response pressure 3.0 bar)

• For the GB172-24 K and GB172-24 T50:

DHW safety valve (response pressure 10 bar)

• Analogue pressure gauge

DHW heating

• Separate DHW heating is only possible with the Logamax plus GB172 via an indirectly heated DHW cylinder to DIN 4753-3

• Integral DHW heating with the Logamax plus GB172-24 K via a plate heat exchanger with warm start option for rapid availability of DHW at the selected temperature

• Integral DHW heating for the Logamax plus GB172-24 T50 by means of the 48 l DHW cylinder with internal indirect coil, for high DHW convenience on the smallest footprint

• Integral DHW heating for the Logamax plus GB172-14 T120, GB172-14/20 T150 by means of an internal DHW cylinder below with internal indirect coil providing 115 l or 143 l capacity

• Integral DHW heating for the Logamax plus GB172-20 T100S, GB172-14/24 T150S by means of an internal stratification cylinder below with internal indirect coil providing 101 l or 148 l capacity

• Integral DHW heating for the Logamax plus GB172-14/20 T210SR by means of an internal dual mode stratification cylinder below with internal indirect coil providing 204 l capacity

Control components

• Logamatic BC25 base controller with integral burner control unit

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 12

2 Technical description

2.2 Logamax plus GB172/GB172T function principle

2.2.1 Heat exchanger and gas burner unit

Eco

VK VS GAS

Fig. 8 Function diagram

Logamax plus GB172-14/20/24

GB172-14/20/24

RK AKO

6 720 641 280-04.1il

16 10 17

GB172-24 K

5 2

Eco

VK AW GAS EK RK AKO

6 720 641 280-101.1il

7 8

13 23

Fig. 9 Function diagram

Logamax plus GB172-24 K

AKO Condensate drain GAS Gas connection RK Boiler return RS Cylinder return VK Boiler flow VS Cylinder flow 1 Air/flue gas connection 2 Ignition electrode 3 Monitoring electrode 4 Automatic air vent valve 5 High limit safety cut-out 7 Stainless steel linear radiant burner 8 Displacer 9 Pressure gauge 10 Siphon 11 Flow temperature sensor 12 Logamatic BC25 base controller 13 Three-way diverter valve 14 Drain & fill valve (DFV) 16 Safety valve 17 Heating circuit pump 18 Flue gas temperature limiter 19 Connection for external expansion vessel 20 Gas valve 21 Fan

AKO Condensate drain AW DHW outlet EK Cold water inlet GAS Gas connection RK Boiler return VK Boiler flow 1 Air/flue gas connection 2 Ignition electrode 3 Monitoring electrode 4 Automatic air vent valve 5 High limit safety cut-out 7 Stainless steel linear radiant burner 8 Displacer 9 Pressure gauge 10 Siphon 11 Flow temperature sensor 12 Logamatic BC25 base controller 13 Three-way diverter valve 14 Drain & fill valve (DFV) 16 Safety valve 17 Heating circuit pump 18 Flue gas temperature limiter 19 12 l expansion vessel (factory-fitted) 20 Gas valve 21 Fan 22 DHW heat exchanger 23 Turbine

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 13

2 Technical description

1)2)

VK EZ

GAS RK

AW EK

Fig. 10 Function diagram Logamax plus GB172-24 T50

AKO Condensate drain AW DHW outlet EK Cold water inlet EZ DHW circulation inlet GAS Gas connection RK Boiler return VK Boiler flow 1 Air/flue gas connection 2 Ignition electrode 3 Monitoring electrode 4 Automatic air vent valve 5 High limit safety cut-out 7 Stainless steel linear radiant burner 8 Displacer 9 Pressure gauge 10 Siphon 11 Flow temperature sensor 12 Logamatic BC25 base controller 13 Three-way diverter valve 14 Drain & fill valve (DFV) 16 Safety valve 17 Heating circuit pump 18 Flue gas temperature limiter 19 12 l expansion vessel (factory-fitted) 20 Gas valve 21 Fan 22 DHW return sensor 23 DHW sensor 24 DHW cylinder with internal indirect coil 25 Safety valve, cold water 26 Check valve 27 Flow limiter

GB172-24 T50

2526

2111

6 720 646 236-02.2O

AKO

Cold water inlet (not shown)

Cylinder flow (not shown)

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

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2 Technical description

GAS

VK RK

1 42 5

AKO

GAS

VK RK

1 42 5

AKO

6720648 096-06.1O

Fig. 11 Function diagram Logamax plus

GB172-14 T120, GB172-14/20 T150

AKO Condensate drain AW DHW outlet EK Cold water inlet GAS Gas connection RK Boiler return VK Boiler flow 1 Gas valve 2 Automatic air vent valve 3 Flow temperature sensor 4 Monitoring electrode 5 Fan 6 Air/flue gas connection 7 High limit safety cut-out 8 Ignition electrode 9 Stainless steel linear radiant burner 10 Displacer 11 Flue gas temperature limiter 12 Safety valve 13 Siphon 14 Heating circuit pump 15 Pressure gauge 16 Drain & fill valve (DFV) 17 Three-way diverter valve 18 Magnesium anode 19 DHW cylinder with internal indirect coil 20 Cylinder temperature sensor 21 Logamatic BC25 base controller 22 18 l expansion vessel (part of the standard delivery)

6720648 096-08.1O

Fig. 12 Function diagram Logamax plus

GB172-20 T100S, GB172-14/24 T150S

AKO Condensate drain AW DHW outlet EK Cold water inlet GAS Gas connection RK Boiler return VK Boiler flow 1 Gas valve 2 Automatic air vent valve 3 Flow temperature sensor 4 Monitoring electrode 5 Fan 6 Air/flue gas connection 7 High limit safety cut-out 8 Ignition electrode 9 Stainless steel linear radiant burner 10 Displacer 11 Flue gas temperature limiter 12 Safety valve 13 Siphon 14 Heating circuit pump 15 Pressure gauge 16 Drain & fill valve (DFV) 17 Three-way diverter valve 18 DHW heat exchanger 19 Cylinder primary pump with automatic air vent valve 20 Magnesium anode 21 Stratification cylinder 22 Cylinder temperature sensor 23 Logamatic BC25 base controller 24 18 l expansion vessel (part of the standard delivery)

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 15

GAS

29 30 29 28

1 42 5

AKO

2 Technical description

Fig. 13 Function diagram Logamax plus GB172-14/20 T210SR

AKO Condensate drain AW DHW outlet EK Cold water inlet GAS Gas connection RK Boiler return RS Solar circuit return VK Boiler flow VS Solar circuit flow 1 Gas valve 2 Automatic air vent valve 3 Flow temperature sensor 4 Monitoring electrode 5 Fan 6 Air/flue gas connection 7 High limit safety cut-out 8 Ignition electrode 9 Stainless steel linear radiant burner 10 Displacer 11 Flue gas temperature limiter 12 Safety valve 13 Siphon 14 Heating circuit pump 15 Pressure gauge 16 Drain & fill valve (DFV) 17 Three-way diverter valve 18 DHW heat exchanger 19 Cylinder primary pump with automatic air vent valve 20 Magnesium anode

21 Stratification cylinder 22 Cylinder temperature sensor, solar 23 Cylinder temperature sensor 24 Logamatic BC25 base controller

25 12 l expansion vessel (part of the standard delivery) 26 Solar circuit safety valve 27 Solar expansion vessel 28 Solar circuit pump 29 Gravity brake 30 Solar circuit pressure gauge 31 Solar circuit drain & fill valve (DFV)

The Logamax plus GB172/GB172T is equipped with a sand-cast heat exchanger made from an aluminium-silicon alloy. Heating water and flue gases are routed in countercurrent.

This concept offers the following benefits:

• Compact dimensions

• Easy service and maintenance

• Excellent standard seasonal efficiency [to DIN] of

The stainless steel linear radiant burner of the Logamax plus GB172/GB172T is arranged inside the heat exchanger.

6720648 096-09.1O

with RC35 programming unit

up to 109 %

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 16

2 Technical description

2.2.2 Burner ignition and flame monitoring

Burner ignition

The Logamax plus GB172/GB172T is equipped with cyclic ignition that takes the form of an ignition electrode.

Flame monitoring system

Should the burner fail to ignite or the flame go out, the Logamatic BC25 base controller receives no flame signal from the monitoring electrode (Æ Fig. 8 and Fig. 9, pos. 3). The BC25 then immediately interrupts the gas supply to the gas valve, switches the burner off and issues a fault message.

2.2.3 Heating circuit pump and hydraulics

The Logamax plus GB172/GB172T gas condensing boiler incorporates a modulating high efficiency (HE) pump (energy efficiency category A) that operates with output or differential pressure-dependent control, thereby ensuring quiet system operation.

2.2.4 Combustion air supply and flue gas routing

The fan (Æ Fig. 8 and Fig. 9, pos. 21) draws in the combustion air required for the combustion process. The positive combustion air pressure transports the flue gas created during combustion into the flue system.

2.2.5 Gas:air control

Gas:air mixing unit

For the Logamax plus GB172/GB172T, the gas:air mixing unit comprises a fan, gas valve and venturi nozzle. Subject to the fan speed and the resulting air flow rate, a specific negative pressure is created inside the venturi nozzle. The required gas volume is metered through this negative pressure. The gas and combustion air are fully mixed inside the fan.

The result of the gas-air mixture control is a constantly high CO

content in the flue gas across the entire burner

modulation range.

Control sequence

Subject to the outside temperature and the heating curve, the controller calculates a set flow temperature. This is transferred to the BC25 base controller and compared with the actual temperature captured by the flow temperature sensor. Output is modulated if this comparison results in a differential, the so-called control deviation.

The gas:air mixing device throttles back the gas supply or shuts it off completely if the fan stops working or if either the combustion air or flue path are blocked. If the gas flame goes out, the Logamax plus GB172/GB172T gas condensing boiler will be shut down by the integral flame monitor, and the Logamatic BC25 issues a fault message.

For information regarding the operating and fault messages at the Logamatic BC25 Æ page 45 f. base controller.

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 17

2.3 Logamax plus GB172/GB172T dimensions and specification

2.3.1 Dimensions and connections

Logamax plus GB172

2 Technical description

≥ 100226 ± 5

Ø125

Ø80

160

151

840

911

915

440

≥ 20≥ 20

Fig. 14 Logamax plus GB172 dimensions and connections (dim. in mm)

350

165*

102*

75*

63*

65 65 65 65 46

338

200

785

6 720 641 280-05.2O

1 Casing 2 Fascia 3 Mounting rail 4 Cylinder flow/DHW (appliance G ½ , accessory R ½ ) 5 Heating flow (appliance G ¾ , accessory R ¾ ) 6 Connection DN 40 siphon (accessory) 7 Heating return (appliance G ¾ , accessory R ¾ ) 8 Cylinder return/cold water

(appliance G ½ , accessory R ½ )

9 Gas (appliance G 1, accessories either R ½ or R ¾ )

Plug-in depth for flue components

* Dimensions apply when using accessories U-MA and

AS6-UP.

200 mm

= =

30 mm

G ½ G ½

R ½

R ¾ R ¾

50 mm

(R ¾)

260 mm

120 - 130 mm

= =

6 720 642 677-01.1O

Fig. 15 Dimensions, U-MA mounting plate

28 mm

35 mm

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 18

2 Technical description

GB172-24 T50

≥ 100226 ± 5

151

452

50 50

600

≥ 200

880

293

482

125

940

600

945

890*

165*

863

102*

75*

63*

200

65 65 65 65 46

100

9 8 7

6 720 646 236-15.2O

Fig. 16 Logamax plus GB172-24 T50 dimensions and connections (dim. in mm)

1 Casing 2 Fascia 3 Mounting rail 4 DHW (appliance G ½ , accessory R ½ ) 5 Heating flow (appliance G ¾ , accessory R ¾ ) 6 Connection DN 40 siphon (accessory)

30 mm

7 Heating return (appliance G ¾ , accessory R ¾ ) 8 Cold water (appliance G ½ , accessory R ½ ) 9 Gas (appliance G 1, accessories either R ½ or R ¾ ) * Dimensions apply when using accessories U-MA and

G ½ G ½

AS6-UP

R ¾ R ¾

50 mm

200 mm

= =

28 mm

R ½

(R ¾)

260 mm

120 - 130 mm

= =

35 mm

6 720 642 677-01.1O

Fig. 17 Dimensions, U-MA mounting plate

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 19

GB172-.. T120/T150 and GB172-.. T100S/T150S

≥ 100226 ± 5

151

600≥ 400 ≥ 400

411

2 Technical description

Ø125

Ø80

8,5

300 300

215 215

600

6 720 648 096-10.1O

Fig. 18 Dimensions and connections for the GB172-14 T120, GB172-14/20 T150, GB172-20 T100S,

GB172-14/24 T150S, (dim. in mm)

Dimensions only in connection with the side connection set (accessory)

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 20

2 Technical description

Key to Fig. 18: 1 DHW circulation G ½

2 Gas G ½ 3 Cold water G ¾ 4 Heating flow G ¾ 5 Heating return G ¾ 6 DHW G ¾

A B C D E F G

GB172-20 T100S 668 723 778 883 888 943 1590

GB172-14 T120 775 830 885 940 995 1050 1695

GB172-14/20 T150 925 980 1035 1090 1145 1200 1845

GB172-14/24 T150S 928 985 1039 1091 1149 1203 1843

H J K L M N

GB172-20 T100S 1515 684 723 778 888 693

GB172-14 T120 1620 791 830 885 995 800

GB172-14/20 T150 1770 941 980 1035 1145 950

GB172-14/24 T150S 1774 982 985 1039 1149 972

Table 6 Dimensions Logamax plus GB172-20 T100S, GB172-14 T120, GB172-14/20 T150, GB172-14/24 T150S

(dim. in mm)

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 21

2 Technical description

≥ 150

~1424 (GB172-... T100S)

T150S)

~1683 (GB172-...

~1529 (GB172-... T120)

~1679 (GB172-... T150)

100S)

1543 (GB172-...T

1648 (GB172-... T120)

1798 (GB172-... T150/150S)

6 720 648 096-20.1O

Fig. 19 Connections for the GB172-14 T120,

GB172-14/20 T150, GB172-20 T100S, GB172-14/24 T150S (dim. in mm) in connection with the rear connection set (accessory)

G ¾ G ¾G ¾ G ¾

100 90

396

68 68 68 68 68

6 720 648 096-07.1O

Fig. 21 Connections for the GB172-14 T120,

GB172-14/20 T150, GB172-20 T100S, GB172-14/24 T150S (dim. in mm) in connection with the top connection set (accessory)

G ¾

G ½

G ¾

6720648096-16.1O

G ¾

G ½

210

Fig. 22 Dimension for the top connection set

(accessory)

Rp ¾ Rp ¾ Rp ¾ Rp ¾ Rp ¾

6 720 648 096-17.1O

Fig. 20 Dimension for the rear connection set

(accessory)

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 22

2 Technical description

GB172-14/20 T210SR

≥400 ≥400

600

150

411

Ø125

Ø80

1235

1180

1125

1070

1015

1290

Fig. 23 Dimensions and connections for the GB172-14/20 T210SR (dim. in mm)

1 DHW circulation G ½ 2 Gas G ½ 3 Cold water G ¾ 4 Heating flow G ¾ 5 Heating return G ¾ 6 DHW G ¾

1) Dimensions only in connection with side connection set

(accessory)

600

1935

1860

8,5

6 720 646 517-06.2O

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 23

≥400 ≥400

600

2 Technical description

446

Ø125

Ø80

1935

1290

1235

1125

1070

1015

1180

1860

8,5

735

6 720 648 096-21.2O

Fig. 24 Dimensions and connections for the GB172-14/20 T210SR (dim. in mm) with rear side panel (accessory,

incl. long side connection set)

1 DHW circulation G ½ 2 Gas G ½ 3 Cold water G ¾ 4 Heating flow G ¾ 5 Heating return G ¾ 6 DHW G ¾

1) Dimensions only in connection with rear side connection

set (accessory incl. long side connection set)

696

735

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

194

6720648096-18.1O

Fig. 25

1) Relevant depth dimension without side panels

Page 24

2 Technical description

4 3

6 720 646 517-07.1O

Fig. 26 Rear view: Dimensions and connections for the GB172-14/20 T210SR (dim. in mm)

1 DHW circulation G ½ 2 Gas G ½ 3 Cold water G ¾ 4 Heating flow G ¾ 5 Heating return G ¾ 6 DHW G ¾ 7 Solar return (15 mm locking ring fitting) 8 Solar flow (15 mm locking ring fitting)

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 25

2 Technical description

2.3.2 Specification

Logamax plus Unit GB172-14 GB172-20 GB172-24 GB172-24 K GB172-24 T50 Output

Maximum rated output (P Maximum rated output (P Maximum rated output (P Maximum rated heat input (Q Minimum rated output (P Minimum rated output (P Minimum rated output (P Minimum rated heat input (Q

) 40/30 °C kW 14.2 20.6 23.8 23.8 23.8

max

) 50/30 °C kW 14.0 20.4 23.6 23.6 23.6

max

) 80/60 °C kW 13.0 19.5 22.5 22.5 22.5

max

) heating kW 13.3 20.0 23.1 23.1 23.1

max.

) 40/30 °C kW 3.3 5.2 7.3 7.3 7.3

min

) 50/30 °C kW 3.2 5.1 7.3 7.3 7.3

min

) 80/60 °C kW 2.9 4.7 6.6 6.6 6.6

min

) heating kW 3.0 4.8 6.8 6.8 6.8

min

Maximum rated heat output (PnW), DHW kW 15.1 23.8 29.7 29.7 29.7 Maximum rated heat input (Q Appliance efficiency, max. output,

heating curve 80/60 °C Appliance efficiency, max. output,

heating curve 50/30 °C Standard seasonal efficiency [to DIN],

heating curve 75/60 °C Standard seasonal efficiency [to DIN],

heating curve 40/30 °C

) DHW kW 14.4 24.0 30.0 30.0 30.0

% 97.5 97.5 97.5 97.5 97.5

% 105.5 102.2 102.2 102.2 102.2

% 105 104 104 104 104

% 109 109 109 109 109

Standby heat loss (incl. electrical losses) % 0.63 0.42 0.36 0.36 0.71

Gas supply rate

Natural gas LL (H Natural gas E (H

°C = 8.1 kWh/m3) m3/h 0.37–1.77 0.59–2.95 0.84–3.70 0.84–3.70 0.84–3.70

i(15)

) °C = 9.5 kWh/m3)m

i(15

/h 0.32–1.52 0.51–2.53 0.72–3.18 0.72–3.18 0.72–3.18

LPG (Hi = 12.9 kWh/kg) Propane Butane

kg/h kg/h

0.35–1.09

0.41–1.25

0.36–1.82

0.41–2.07

0.56–2.27

0.66–2.62

0.56–2.27

0.66–2.62

0.56–2.27

0.66–2.62

Permissible gas supply pressure

Natural gas LL and natural gas E mbar 17–25 17–25 17–25 17–25 17–25 LPG mbar 42.5–57.5 42.5–57.5 42.5–57.5 42.5–57.5 42.5–57.5

Expansion vessel

Pre-charge pressure bar – – – 0.75 0.75 Total capacity l – – – 12 12

Condensate

Max. condensate quantity (TR = 30 °C) l/h 1.4 2.2 2.6 2.6 2.6 pH level, approx. – 4.8 4.8 4.8 4.8 4.8

Calculation values for calculating cross-section to EN 13384

Flue gas connection to EN 483 – B

/ B33 / C

13x

/ C

33x

/ C

43x

/ C

53x

/ C

63x /C83x /C93x

Flue gas mass flow rate at max./min. rated output g/s 6.3/1.4 10.5/2.3 13.1/3.2 13.1/3.2 13.1/3.2 Flue gas temperature 80/60 °C max./min. rated

heating output Flue gas temperature 40/30 °C max./min. rated

heating output

°C 65/58 75/58 90/57 90/57 90/57

°C 49/30 58/36 60/32 60/32 60/32

Standard CO emissions factor mg/kWh ≤ 10 ≤ 20 ≤ 15 ≤ 15 ≤ 15 Standard NOX emissions factor mg/kWh ≤ 35 ≤ 35 ≤ 35 ≤ 35 ≤ 35 Available fan draught Pa 80 80 80 80 80 CO2 at max. rated heating output % 9.4 9.4 9.4 9.4 9.4 CO

at min. rated heating output % 8.6 8.6 8.6 8.6 8.6

Table 7 Logamax plus GB172 specification

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 26

2 Technical description

Logamax plus Unit GB172-14 GB172-20 GB172-24 GB172-24 K GB172-24 T50

Flue gas rating group to G 636/G 635 – G61/G62G61/G

62G61/G62

G61/G

NOx class – 5 5 5 5 5

DHW

Cylinder capacity l – – – – 48 Coefficient of performance N

– – – – 0.8 Constant DHW output at 80/45/10 °C l/h – – – – 690 Maximum amount of DHW l/min – – – 9 14 Outlet temperature range °C – – – 40 60 40-60 Maximum cold water inlet temperature °C – – – 60 65 Maximum permissible DHW pressure bar – – – 10 10 Minimum cold water supply pressure bar – – – 0.2 0.2 Specific throughput to EN 625 (D) l/min – – – 14.1 16.6 Standby energy losses (24 h) to

DIN 4753-8

kWh/d – – – – 1.8

General data

Voltage VAC 230 230 230 230 230 Frequency Hz 50 50 50 50 50 Max. power consumption (central heating mode) W 65 67 75 75 75 Power consumption, partial load W 21 21 21.5 21.5 21.5 EMC limit class – B B B B B Noise output level dB(A) ≤ 36 ≤ 36 ≤ 36 ≤ 36 ≤ 36 Appliance enclosure rating IP X4D X4D X4D X4D X4D Maximum flow temperature °C 82 82 82 82 82 Maximum permissible operating pressure (PMS),

central heating

bar 3 3 3 3 3

Permissible ambient temperature °C 0–50 0–50 0–50 0–50 0–50 Water content (central heating) l 7.0 7.0 7.0 7.0 7.0 Weight (excluding packaging) kg 43 43 43 44 78

Dimensions, W x H x D mm

440 × 840

× 350

440 × 840

×350

440 × 840

×350

440 × 840

× 350

600 × 880

× 482

Table 7 Logamax plus GB172 specification

1) Distribution losses outside the cylinder have not been taken into consideration.

Logamax plus Unit GB172-14 T... GB172-20 T... GB172-24 T... Output

Maximum rated output (P Maximum rated output (P Maximum rated output (P Maximum rated heat input (Q Minimum rated output (P Minimum rated output (P Minimum rated output (P Minimum rated heat input (Q

) 40/30 °C kW 14.2 20.6 23.8

max

) 50/30 °C kW 14.0 20.4 23.6

max

) 80/60 °C kW 13.0 19.5 22.5

max

) heating kW 13.3 20.0 23.1

max.

) 40/30 °C kW 3.3 5.2 7.3

min

) 50/30 °C kW 3.2 5.1 7.3

min

) 80/60 °C kW 2.9 4.7 6.6

min

) heating kW 3.0 4.8 6.8

min

Maximum rated heat output (PnW), DHW kW 15.1 23.8 29.7 Maximum rated heat input (Q

) DHW kW 14.4 24.0 30.0

Appliance efficiency, max. output, heating curve 80/60 °C % 97.5 97.5 97.5 Appliance efficiency, max. output, heating curve 50/30 °C % 105.5 102.2 102.2

Table 8 Logamax plus GB172 specification

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 27

Logamax plus Unit GB172-14 T... GB172-20 T... GB172-24 T...

Standard seasonal efficiency [to DIN], heating curve 75/60 °C % 105 104 104 Standard seasonal efficiency [to DIN], heating curve 40/30 °C % 109 109 109 Standby heat loss (incl. electrical losses) % 0.63 0.42 0.36

Gas supply rate

Natural gas LL (H Natural gas E (H

°C = 8.1 kWh/m3) m3/h 0.37 - 1.77 0.59 - 2.95 0.84 - 3.70

i(15)

) °C = 9.5 kWh/m3)m

i(15

/h 0.32 - 1.52 0.51 - 2.53 0.72 - 3.18

LPG (Hi = 12.9 kWh/kg) Propane Butane

kg/h kg/h

0.35 - 1.09

0.41 - 1.25

0.36 - 1.82

0.41 - 2.07

0.56 - 2.27

0.66 - 2.62

Permissible gas supply pressure

Natural gas LL and natural gas E mbar 17 - 25 17 - 25 17 - 25 LPG mbar 42.5 - 57.5 42.5 - 57.5 42.5 - 57.5

Expansion vessel

Pre-charge pressure bar 1.9 1.9 1.9 Total capacity l 18 18 18

Condensate

Max. condensate quantity (TR = 30 °C) l/h 1.2 1.7 1.7 pH level, approx. – 4.8 4.8 4.8

Calculation values for calculating cross-section to EN 13384

Flue gas connection to EN 483 – B

/ B33 / C

13x

/ C

33x

/ C

43x

/ C

53x

/ C

63x /C83x /C93x

Flue gas mass flow rate at max./min. rated output g/s 6.3/1.4 10.5/2.3 13.1/3.2 Flue gas temperature 80/60 °C max./min. rated heating output °C 65/58 75/58 90/57 Flue gas temperature 40/30 °C max./min. rated heating output °C 49/30 58/36 60/32 Standard CO emissions factor mg/kWh ≤ 10 ≤ 20 ≤ 15 Standard NOX emissions factor mg/kWh ≤ 35 ≤ 35 ≤ 35 Available fan draught Pa 80 80 80 CO2 at max. rated heating output % 9.4 9.4 9.4 CO

at min. rated heating output % 8.6 8.6 8.6

Flue gas rating group to G 636/G 635 – G61/G

G61/G

NOx class – 5 5 5

DHW

Æ Table 14, page 35 and table 15, page 36

General data

Voltage V AC 230 230 230 Frequency Hz 50 50 50 Max. power consumption (central heating mode) W 65 63 61 Maximum power consumption, cylinder operation W 106 106 112 EMC limit class – B B B Noise output level dB(A) ≤ 36 ≤ 36 ≤ 36 Appliance enclosure rating IP X4D X4D X4D Maximum flow temperature °C 82 82 82 Maximum permissible operating pressure (P

), central heating bar 3 3 3

Permissible ambient temperature °C 0 - 50 0 - 50 0 - 50 Water content (central heating) l 7.0 7.0 7.0

Weight (excluding packaging) kg

Æ Table 14, page 35 and

table 15, page 36

123

Dimensions, W x H x D mm Æ Table 6 page 20

Table 8 Logamax plus GB172 specification

2 Technical description

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 28

2 Technical description

2.3.3 Parameters for calculation to EnEV [Germany]

For assigning burners, all models are categorised as “premix gas burners with fan gas:air mixing unit”.

Boiler size in kW

n 50/30

in kW

n 80/60

in kW

100%

in %

30%

in %

B 70

in %

in kWh/d

HE100%

in W

GB172-14 14.0 13.0 97.5 108.0 0.63 – 65

GB172-20 20.0 19.0 97.5 107.0 0.42 – 65

GB172-24 23.6 22.5 97.5 107.0 0.36 – 75

GB172-24 K 23.6 22.5 97.5 107.0 0.36 3.00 75

GB172-24 T50 23.6 22.5 97.5 107.0 0.71 1.90 75

GB172-14 T120 14.0 13.0 97.5 108.0 0.63 1.47 65

GB172-14 T150 14.0 13.0 97.5 108.0 0.63 1.65 65

GB172-20 T150 20.0 19.0 97.5 107.0 0.42 1.65 65

GB172-20 T100S 20.0 19.0 97.5 107.0 0.42 1.22 65

GB172-14 T150S 14.0 13.0 97.5 108.0 0.63 1.22 65

GB172-24 T150S 23.6 22.5 97.5 107.0 0.36 1.22 75

GB172-14 T210SR 14.0 13.0 97.5 108.0 0.63 2.222)/0.51

GB172-20 T210SR 20.0 19.0 97.5 107.0 0.42 2.222)/0.51

HE30%

in W

Table 9

1) Power consumption with integral pump

2) to DIN 4753-8 or EN 12897 (actual value at 45 K temperature differential, total cylinder content heated up)

3) to DIN V4701-10 (value calculated in accordance with the standard)

HE30%

HE100%

B 70

Q Q

30%

100%

Power consumption at 30 % partial load operation Power consumption at rated output Standby loss at an average boiler temperature of 70 °C Standby loss of the DHW cylinder Rated output at 50/30 °C

n 50/30

Rated output at 80/60 °C

n 80/60

Efficiency at 30 % partial load operation Efficiency at rated output

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 29

2.4 Dimensions and specification of DHW cylinders

2.4.1 Logalux H65 W DHW cylinders

2 Technical description

314

300

130

100

185

230

840

440 130

G /

KW/E

G /

370

24,5

G /

230

6 720 614 356-01.3O

314

Fig. 27 Dimensions and connections of the Logalux H65 W DHW cylinder (dim. in mm)

B Dummy connector

(fit cap prior to filling the cylinder)

E Drain KW Cold water connection G ¾ (male thread) MA Magnesium anode

Cylinder return G ¾ (male thread)

SF Cylinder temperature sensor (NTC) VSPCylinder flow G ¾ (male thread) WW DHW outlet G ¾ (male thread)

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 30

2 Technical description

DHW cylinder Logalux Unit H65 W

Internal indirect coil

Number of coils – 12

Heating water content l 3.9

Heating surface m

0.8

Maximum heating water temperature °C 110

Max. operating pressure, heat exchanger bar 4

Maximum heat transfer rate at: T

= 90 °C and TSp = 45 °C to DIN 4708

= 80 °C and TSp = 60 °C

kW kW

25.0

17.7

Maximum constant output at: T

= 90 °C and TSp = 45 °C to DIN 4708

= 85 °C and TSp = 60 °C

l/h l/h

614 230

Flow rate taken into account l/h 765

Performance factor N at T

= 90 °C (maximum cylinder heat input)

to DIN 4708

– 0.5

Minimum heat-up time from T GB172-20 and GB172-24 GB172-14

= 10 °C to TSp = 60 °C with TV = 85 °C at:

min min

17 21

Cylinder capacity

Available capacity l 63

Available amount of DHW (without reheating) TSp = 60 °C and TZ = 45 °C T

= 40 °C

l l

76.5

89.2

Maximum flow rate l/min 10

Maximum operating pressure, water bar 10

Minimum safety valve size (accessory) DN 15

Further details

Standby energy losses (24 h) to DIN 4753-8

kWh/d 1.8

Dry weight (excl. packaging) kg 47

Table 10 Specification of the Logalux H65 W DHW cylinder

1) The performance factor NL corresponds to the number of residential units to be supplied, each with 3.5 occupants, one standard bath tub and two further draw-off points. N surface output. In the case of reduced cylinder heat input and lower flow rate, N

2) Distribution losses outside the cylinder have not been taken into account

was determined according to DIN 4708 at TSp = 60 °C, TZ = 45 °C, TK = 10 °C and at maximum heating

reduces accordingly.

TKCold water inlet temperature

Cylinder temperature

Flow temperature

DHW outlet temperature

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 31

2.4.2 Logalux WU120 W and WU160 W DHW cylinders

2 Technical description

250

357 / 407

315 / 365

600

250 / 300

185 / 235

143/193

120

245

6 720 612 383-02.1R

951*

929*

275

585

R /

200100

120

500 / 600

Rp 1

R /

Fig. 28 Dimensions and connections of the Logalux WU120 W and WU160 W DHW cylinders (dim. in mm)

E Drain KW Cold water connection R ¾ (male thread) L Lead entry, cylinder temperature sensor (NTC) MA Magnesium anode

Cylinder return R ¾ (male thread)

T Contact thermometer for temperature display T1Cylinder temperature sensor (NTC contact sensor)

Cylinder flow R ¾ (male thread)

WW DHW outlet R ¾ (male thread) ZL DHW circulation connection Rp 1 (female thread)

* The dimensions given refer to the delivered condition

(adjustable feet fully turned in). Turning the adjustable feet can increase this dimension by up to 16 mm.

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 32

2 Technical description

DHW cylinder Logalux Unit WU120 W WU160 W

Internal indirect coil

Number of coils – 5 5

Heating water content l 4.4 4.4

Heating surface m

0.63 0.63

Maximum heating water temperature °C 110 110

Max. operating pressure, heat exchanger bar 4 4

Maximum heat transfer rate at: T

= 90 °C and TSp = 45 °C to DIN 4708

= 85 °C and TSp = 60 °C

kW kW

25.1

13.9

25.1

13.9

Maximum constant output at: T

= 90 °C and TSp = 45 °C to DIN 4708

= 85 °C and TSp = 60 °C

l/h l/h

590 237

Flow rate taken into account l/h 1300 1300

Performance factor N at T

= 90 °C (maximum cylinder heat input)

to DIN 4708

– 1.3 2.0

Minimum heat-up time from T 24 kW Speicherladeleistung 18 kW cylinder heat input

= 10 °C to TSp=60°C with TV = 85 °C at:

min min

20 25

26 32

Cylinder capacity

Available capacity l 115 149

Available amount of DHW (without reheating) TSp = 60 °C and TZ = 45 °C T

= 40 °C

l l

145 170

190 222

Maximum flow rate l/min 12 16

Max. operating pressure, water bar 6 6

Minimum safety valve size (accessory) – DN 15 DN 15

Further details

Standby energy losses (24 h) to DIN 4753-8

kWh/d 1.2 1.4

Dry weight (excl. packaging) kg 50 60

Table 11 Specification of the Logalux WU120 W and WU160 W DHW cylinders

2) Distribution losses outside the cylinder have not been taken into account

was determined according to DIN 4708 at TSp = 60 °C, TZ = 45 °C, TK = 10 °C and at maximum heating

reduces accordingly

TKCold water inlet temperature

Cylinder temperature

Flow temperature

DHW outlet temperature

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 33

2.4.3 Logalux S120 W, SU160 W, SU200 W and SU300 W DHW cylinders

2 Technical description

Logalux SU...W Logalux S120 W Logalux S120 W

R 1

EZ R ¾ VS

R 1 M

∅19

RS R 1

EK R 1

H H

15–25

174

HEKH

HVSH

15–25

R ¾

130

EK R ¾

R ¾

218

R ¾

150

6 720 646 236-19.1il

Fig. 29 Dimensions and connections of the Logalux S120 W, SU160 W, SU200 W and SU300 W DHW cylinders

(dim. in mm)

AW DHW outlet R ¾ (male thread) EL Drain EK Cold water inlet R ¾ (male thread) EZ DHW circulation inlet RS Cylinder return R ¾ (male thread) VS Cylinder flow R ¾ (male thread)

Sensor well for DHW temperature sensor

Top view

Dimensions Unit S120 W SU160 W SU200 W SU300 W

Ø D mm 512 556 556 672

H mm 956 1188 1448 1465

Installation room height

ØEK H

mm 1460 1718 2053 1845

mm 975 644 644 682

mm 975 238 238 297

inch

mm –

R¾ 980

R¼

724 724 762

mm 980 1111 1371 1326

Table 12 Dimensions Logalux S120 W, SU160 W, SU200 W and SU300 W

1) Minimum room height for the replacement of the magnesium anode

2) For the Logalux S120 W, we recommend connecting the DHW circulation line to the cold water inlet

Cold water inlet temperature

Cylinder temperature

TVFlow temperature T

DHW outlet temperature

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 34

2 Technical description

DHW cylinder Logalux Unit S120 W SU160 W SU200 W SU300 W

Internal indirect coil

Heating water content, smooth tube internal indirect coil

Max. operating temperature, heating water side

Max. operating pressure, heating water side

l 5 4.5 4.5 8

°C 110 160 160 160

bar 6 16 16 16

Constant DHW output at :

= 80 °C, TZ = 45 °C, TK = 10 °C

with GB172-14 with GB172-20 with GB172-24

Performance factor N with GB172-14 with GB172-20 with GB172-24

to DIN 4708

l/h l/h l/h

370 490 490

– 1.2

1.3

1.4

370 526 526

2.2

2.3

370 526 526

3.7

4.0

370 526 526

7.2

8.7

Cylinder capacity

Cylinder capacity l 120 160 200 300

Max. operating temperature, DHW side

°C 95 95 95 95

Max. operating pressure, DHW side bar 10 10 10 10

Further details

Standby energy loss2) (24 h) to DIN 4753-8

kWh/d 1.68 1.8 2.0 2.1

Dry weight (excl. packaging) kg 72 98 110 145

Certificate no. acc. to Pressure Equipment Directive

Z-DDK-MUC-

02-318302-11

P-DDK-MUC-02-318302-15

Part number 7 747 011 041 7 747 003 781 7 747 003 782 7 747 003 783

Table 13 Specification of the Logalux S120 W, SU160 W, SU200 W and SU300 W DHW cylinders

2) At TSp 65 °C and room temperature 20 °C

TKCold water inlet temperature

Cylinder temperature

TVFlow temperature

DHW outlet temperature

was determined according to DIN 4708 at TSp = 60 °C, TZ = 45 °C, TK = 10 °C and at maximum heating

reduces accordingly

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 35

2 Technical description

2.4.4 Cylinder in compact heating centres Logamax plus GB172-14 T120, GB172-14 T150, GB172-14 T150S

and GB172-14 T210SR

Unit

GB172-14

T120

GB172-14

T150

GB172-14

T150S

GB172-14

T210 SR

Available capacity l 115 143 148 204

Solar contribution l – – – 154

Outlet temperature range °C 40 - 70 40 - 70 40 - 70 40 - 70

Maximum flow rate l/min 13.0 16.5 16.5 12.0

Maximum power consumption (cylinder heating) W 84 84 106 182

Specific throughput to EN 625 (D) l/min 17.9 17.0 22.6 20.7

Standby energy consumption (24 h) to DIN 4753 part 8

kWh/d 1.65 1.65 1.22 2.2

Maximum operating pressure (PMW) bar 10 10 10 10

Maximum continuous output at:

- T

= 75 °C and TSp = 45 °C

l/h

352

–

to DIN 4708

- T

= 75 °C and TSp = 60 °C

Minimum heat-up time of TK = 10 °C to T

= 60 °C with TV = 75 °C

Performance factor N T

= 75 °C (maximum cylinder heat input)

to DIN 4708 at

l/h

248

min. 30 38 45 31

– 1.4 2.1 3.0 1.8

Weight (excluding packaging) kg 115 123 123 166

Table 14

1) Standard comparison values; excluding distribution losses outside the cylinder.

2) The performance factor NL corresponds to the number of residential units to be supplied, each with 3.5 occupants, one standard bath tub and

two further draw-off points. N

TV= Flow temperature

= Cylinder temperature

TK= Cold water inlet temperature

= DHW outlet temperature

was determined to DIN 4708 at TSp = 60 °C, TZ = 45 °C, TK = 10 °C and at maximum heat transfer rate.

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 36

2 Technical description

2.4.5 Cylinder in compact heating centres Logamax plus GB172-20 T100S, GB172-20 T150,

GB172-24 T150S and GB172-20 T210SR

Unit

GB172-20

T100S

GB172-20

T150

GB172-20

T210SR

GB172-24

T150S

Available capacity l 101 143 204 148

Solar contribution l – – 154 –

Outlet temperature range °C 40 - 70 40 - 70 40 - 70 40 - 70

Maximum flow rate l/min 13.0 16.5 12.0 16.5

Maximum power consumption (cylinder heating) W 106 106 182 113

Specific throughput to EN 625 (D) l/min 22.0 22.9 24.11 31.6

Standby energy consumption (24 h) to DIN 4753 part 8

kWh/d 1.22 1.65 2.2 1.22

Maximum operating pressure (PMW) bar 10 10 10 10

Maximum continuous output at:

- T

= 75 °C and TSp = 45 °C

l/h

–

586

–

to DIN 4708

- T

= 75 °C and TSp = 60 °C

Minimum heat-up time from TK = 10 °C to T

= 60 °C with TV = 75 °C

Performance factor N T

= 75 °C (maximum cylinder heat input)

to DIN 4708 at

l/h

413

516

min. 22 29 20 23

– 2.2 2.3 2.3 4.6

Weight (excluding packaging) kg 108 123 166 123

Table 15

1) Standard comparison values; excluding distribution losses outside the cylinder.

2) The performance factor NL corresponds to the number of residential units to be supplied, each with 3.5 occupants, one standard bath tub and two further draw-off points. N

TV= Flow temperature

= Cylinder temperature

TK= Cold water inlet temperature

= DHW outlet temperature

was determined to DIN 4708 at TSp = 60 °C, TZ = 45 °C, TK = 10 °C and at maximum heat transfer rate.

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 37

2.5 Installation dimensions Logamax plus GB172

2.5.1 Logamax plus GB172 installation dimensions excluding DHW cylinder

To make the installation on the gas supply and water side easier, a special mounting frame is available as an accessory for the Logamax plus GB172 (part no.: 7 736 995 014). This mounting frame is unsuitable for the GB172-24 T50. The mounting frame is supplied separately and can be preinstalled without the appliance.

403

338

≥ 100

AKO Condensate drain ASV Safety valve outlet AW DHW outlet (appliance G ½ , accessory R ½ ) EK Cold water inlet (appliance G ½ , accessory R ½ ) GAS Gas connection (appliance G 1, accessories either

R½or R¾)

RK Boiler return (appliance G ¾ , accessories R ¾ ) RS Cylinder return G ½ VK Boiler flow (appliance G ¾ , accessories R ¾ ) VS Cylinder flow G ½ 1 Mounting frame for Logamax plus GB172

(accessory in place of the mounting rail supplied and the mounting plate available as an accessory); not suitable for the GB172-24 T50

2 Technical description

226 ± 5

13 ± 0,2

785

151

200

100 mm are recommended for installation. For the Logamax plus GB172 with single wall flue, maintain clearances ≥ 50 mm. No other minimum clearances are specified by DVGW-TRGI 2008.

AW and EK only fitted to Logamax plus GB172-24 K with integral DHW heating

VS and RS connection as standard for Logamax plus GB172-14, GB172-20 and GB172-24 If no DHW cylinder is connected, the DHW caps ½ " are required (accessories Æ page 96 ff.).

840

102

165

EK RS

65 46

AKO ASV

6 720 646 236-07.1il

GAS

Fig. 30 Installation dimensions for connection

assembly (unfinished walls) for the Logamax plus GB172 (dim. in mm)

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 38

2 Technical description

2.5.2 Installed dimensions Logamax plus GB172-24 T50 with integral DHW cylinder

AW DHW outlet (appliance G ½ , accessory R ½ ) EK Cold water inlet (appliance G ½ , accessory R ½ )

≥100

600 452

GAS Gas connection (appliance G 1, accessories either

R½or R¾)

RK Boiler return (appliance G ¾ , accessories R ¾ ) VK Boiler flow (appliance G ¾ , accessories R ¾ )

≥50 ≥50

220±5

145

890165*

863

200

880

1 Mounting Bracket

100 mm are recommended for installation. For the Logamax plus GB172 with single wall flue, maintain clearances ≥ 50 mm. No other minimum clearances are specified by DVGW-TRGI 2008.

Connection DN 40 siphon (accessory)

AW EKGAS

VK RK

65 65 65 65 46

102*

6 720 646 236-08.2O

75*

63*

Fig. 31 Installation dimensions for connection

assembly (unfinished walls) for the Logamax plus GB172-24 T50 (dim. in mm)

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 39

2 Technical description

2.5.3 Installation dimensions Logamax plus GB172 with DHW cylinder below the gas condensing boiler

840

≥

100

920

102

Logamax plus

VS RS

65 65 65 65

GB172

440

GAS

AW EK

130

214

500/600

≥ 100

226 ± 5

151

785

840

165

220

AKO

ASV

≥

100

102

Logamax plus

GB172

440

VS RS

GAS

65 65 65 65

VS AW EK RS

130

218

Ø 512

≥ 100

AKO ASV

165

151

840

956

226 ± 5

190-240

Logalux WU120 W/WU160 W

9–25

Logalux S120 W

15–25

6 720 646 236-10.1il

Fig. 32 Installed dimensions of the pipework when using the accessory sets for installation on unfinished walls

(accessories

page 96 ff.) and arrangement of the Logalux WU120 W, WU160 W or S120 W DHW

cylinders below the Logamax plus GB172 (dim. in mm)

AKO Condensate drain ASV Safety valve outlet (siphon G ¾ ) AW DHW outlet G ½ EK Cold water inlet G ½ GAS Gas connection R 1 RK Boiler return G ¾ RS Cylinder return R ¾ (S120 W) or

R ¾ (WU120 W/WU160 W) (male thread)

VK Boiler flow G ¾ VS Cylinder flow R ¾ (S120 W) or

R ¾ (WU120 W/WU160 W) (male thread)

100 mm recommended for installation. For the Logamax plus GB172 with single wall flue, maintain clearances of at least ≥ 50 mm. No other minimum clearances are specified by DVGW-TRGI 2008.

Dimensions after the slash refer to the next largest cylinder version.

Flue system

in mm

Single wall (Ø 80 mm) 2411 2437

Concentric (Ø 80/125 mm) 2361 2387

Table 16 Minimum room height

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 40

2 Technical description

2.5.4 Installation dimensions Logamax plus GB172 with DHW cylinder adjacent to the gas condensing

boiler

≥ 100

314

ASV

226 ± 5

840

251

850

350

AW G ¾

G ¾

151

Logamax plus

GB172

785

440

102

130

GAS

130

395

AKO/ASV

460

525

Logalux H65 W

161

636

314

130

440

130

314

100

185

230

EK G ¾

370

VS G ¾

230

6 720 646 236-11.1il

Fig. 33 Installed dimensions of the pipework when using the accessory sets for installation on unfinished walls

(accessory

page 96 ff.) and arrangement of the Logalux H65 W DHW cylinder adjacent to the

Logamax plus GB172 (dim. in mm)

AKO Condensate drain ASV Safety valve outlet (siphon G ¾ ) AW DHW outlet B Dummy connector (fit caps prior to filling the cylinder) EK Cold water inlet GAS Gas connection R 1 MA Magnesium anode RK Boiler return G ¾ RS Cylinder return SF Cylinder temperature sensor (NTC) VK Boiler flow G ¾ VS Cylinder flow 1 Top view 2 Bottom view

100 mm recommended for installation. For the Logamax plus GB172 with single wall flue, maintain clearances of at least ≥ 50 mm. No other minimum clearances are specified by DVGW-TRGI 2008.

165 mm

Flue system

in mm

Single wall (Ø 80 mm) 1566

Concentric (Ø 80/125 mm) 1516

Table 17 Minimum room height

No clearance is required between the GB172 and the cylinder. The cylinder is supplied with a common mounting rail for mounting the cylinder to the left, right or separately below.

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 41

2.5.5 Installation dimensions Logamax plus GB172 with DHW cylinder

Logalux SU160 W, SU200 W and SU300 W

≥ 100

226 ± 5

151

Logamax plus

GB172

2 Technical description

785

440

63*

75*

102*

165*

15–25

GAS

65 65 65 65 46

840

165

AKO/ASV

6 720 646 236-12.1il

Fig. 34 Installed dimensions of the pipework when using the accessory sets for installation on finished walls

(accessory

page 96 ff.) and arrangement of the Logalux SU160 W, SU200 W and SU300 W DHW

cylinder adjacent to the right or left of the Logamax plus GB172 (dim. in mm)

AKO Condensate drain ASV Safety valve outlet (siphon G ¾ ) AW DHW outlet G ½ GAS Gas connection G 1 RK Boiler return G ¾ RS Cylinder return G ½ (boiler) or G 1 (DHW cylinder) VK Boiler flow G ¾ VS Cylinder flow G ½ (boiler) or G 1 (DHW cylinder)

Connections at the back of the cylinder (Æ Fig. 29, page 33); required clearance for the cylinder connections at the back 100 mm

100 mm recommended for installation. For the Logamax plus GB172 with single wall flue, maintain clearances ≥ 50 mm.

* Dimensions apply when using accessories U-MA and

AS5-UP.

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

in mm

Logamax plus GB172 with DHW cylinder

min. max.

Logalux SU...W 1166 559 1154

Table 18 Minimum room height

Dimension H2 takes account of the minimum and maximum lengths of the corrugated hoses from the N-Flex connection accessories (accessories Æ page 96 ff).

Page 42

3 Regulations and operating conditions

3.1 Extracts from the regulations

The Logamax plus GB172/GB172T gas condensing boilers comply with the standard regulations of the Gas Appliances Directive 90/396/EEC. The requirements of standards EN 483 and EN 677 were taken into consideration.

When installing and operating the system, observe the following:

• Technical building regulations

• Legal regulations

• Local regulations

Installation, gas and flue gas connections, commissioning, power supply as well as maintenance and repair work must only be carried out by authorised contractors.

Permits

The installation of a gas condensing boiler may need to be notified to and approved by the relevant gas supply utility.

Gas condensing boilers may only be operated with a flue gas system that has been designed for the specific boiler type and that has been approved according to relevant building regulations. If the boiler is to be installed in a room designated for constant occupation, a flue system that has been approved for such locations must be allowed for.

Where required, inform your local flue gas inspector and water board prior to installation. Regional approvals with regard to the flue system and the introduction of condensate into the public sewer system may be required.

Maintenance

According to paragraph 10 of the Energy Savings Order (EnEV) [Germany], the system must be correctly operated, maintained and repaired.

We recommend system users enter into a maintenance contract with their local heating contractor covering an annual inspection and any required maintenance. A regular inspection and maintenance are prerequisites for reliable and economical operation.

3.2 Operating requirements

The operating conditions listed in table 19 are part of the warranty conditions for Logamax plus GB172 gas condensing boilers.

Logamax plus

GB172 GB172T

Table 19 Operating conditions Logamax plus GB172

1) Heating circuit control with mixer improves the control characteristics; particularly recommended for systems with several heating circuits

Maximum

flow

temperature

At full output

82 °C may be

reached

Minimum

boiler water

flow rate

Operating conditions (warranty conditions)

Minimum

boiler water

temperature

These operating conditions are safeguarded through an appropriate hydraulic circuit and boiler circuit control (hydraulic integration Æ chapter 6, page 61 ff.).

Operating

interruption (total

boiler shutdown)

No requirements

Heating

circuit control

with mixer

Minimum

return

temperature

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 43

4 Heating controls

4.1 Aims of the Logamatic control system

The Logamatic control system was specifically developed for the control requirements of advanced heating systems in detached houses and two-family homes.

System configurations that exceed the range of functions offered by the Logamatic EMS can be covered by the wider range of functions offered by the Logamatic 4000 control system.

4 Heating controls

The fundamental aims of this new control concept are as follows:

• The optimum utilisation of fossil fuels and electric energy.

• The use of identical control components for wall mounted and floor standing boilers.

• Uniform operation

Maintenance and service are further priorities. Some components in the Logamatic control system are designed to monitor themselves and to issue messages automatically in the case of faults or irregularities. Service functions that are integrated into the programming unit as standard make commissioning, maintenance and troubleshooting easy.

A service tool for connection to a laptop is available and enables extensive service tasks.

ASM10

MM10

WM10

SM10

Fig. 35 Overview of the Logamatic control system

ASM10 Connection module BC25 Base controller EM10 Fault message module MM10 Mixer module RC25 Programming unit RC20 RF Wireless programming unit RC35 Programming unit RFM20 Wireless module

4.2 Logamatic EMS control concept

At the core of the Logamatic EMS control system is the digital base controller BC25 with integral burner control unit, that not only controls and monitors the burner but also takes care of the boiler safety functions. This covers several standard control functions (Æ page 45 f.).

BC25

EMS-BUS

RC25RC35

EM10

SM10 Solar module VM10 Function module Web KM200 Interface for controlling the heating system via

WM10 Low loss header module

VM10

iPhone, iPod touch or iPad

Up to 3 pce with RC35 Telecontrol modem

RC20 RF

Logamatic Easycom

RFM20

Web KM200

6 720 641 280-11.2O

No modules can be fitted into the Logamax plus GB172/GB172T as condensing boilers. They can only be wall mounted (Æ page 49). Alternatively, heating circuit quick installation sets with integral EMS modules (EMS Inside) can be used.

The EMS-BUS provides a second means of communication. Control components and modules without boiler-specific functions are connected to this BUS via a 2-core cable (Æ Table 24, page 55). These components include the RC35 and RC25/RC20 RF plus the function modules (mixer, low loss header and solar modules).

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Activating, adjusting and setting of parameters for the function modules of the Logamatic EMS control system always require the RC35 programming unit (Æ Table 24 page 55).

Page 44

4 Heating controls

The Logamatic EMS control system enables room temperature-dependent and weather-compensated control.

The Logamatic EMS control system is tailored to standard systems and offers a fixed range of functions (system examples Æ page 72 ff.). This range of functions cannot and must not be exceeded.

4.3 Types of controls

4.3.1 Room temperature-dependent control

With room temperature-dependent control, the heating system or the heating circuit is regulated subject to the temperature in a reference room. For this kind of control, the RC25/RC20 RF or RC35 programming units are suitable; these have an integral room temperature sensor. For that reason, the RC25/RC20 RF and RC35 programming units are installed in the reference room to provide room temperature-dependent control (Æ Fig. 36).

An external room temperature sensor can also be connected to the RC35 programming unit if it cannot be installed in the reference room in a position that would be both favourable to capturing the room temperature and still be in a convenient position for the user.

4.3.2 Weather-compensated control

With weather-compensated control, the heating system is regulated subject to the outside temperature.

This method of control requires a RC35 programming unit. The RC35 programming unit can be installed in the boiler and is supplied, if required, with the necessary outside temperature sensor.

Position of the outside temperature sensor

Install the outside temperature sensor so that it captures the outside temperature without extraneous influences ( Æ Fig. 37). Therefore always install it on the north side of the building.

For optimum temperature capture, avoid the following temperature sensor positions:

• Not above windows, doors or vents

• Not underneath awnings, balconies or below the roof

Position of the Room temperature sensor

Install the room temperature sensor in the reference room so that negative influences are prevented.

• Not on an outside wall

• Not close to windows or doors

• Not near to thermal bridges

• Not in “dead spots”

• Not above radiators

• Not in direct sunlight

• Not in the path of direct heat radiation from electrical

appliances or similar

RC25/RC20 RF

RC35

≥ 1,50

≥ 0,75

≥ 0,6

≥ 1

6 720 641 280-100.1il

≥ 2,5

7 747 009 801-16.1il

Fig. 37 Arrangement of the outside temperature sensor

(dim. in mm)

1 Incorrect arrangement 2 Correct arrangement

4.3.3 Weather-compensated control with room temperature hook-up

The weather-compensated control with room temperature hook-up combines the benefits of both previously mentioned kinds of control.

This kind of control requires the installation of the RC35 programming unit, an external room temperature sensor, or an additional RC25/RC20 RF programming unit inside the reference room (Æ Fig 36).

Fig. 36 Position of the RC25/RC20 RF or RC35

programming unit or the external room temperature sensor in the reference room (dim. in m)

1 Required clearance below the RC25, RC20 RF or RC35

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 45

4.4 Boiler and control components in the Logamatic EMS control system

4.4.1 Logamatic BC25 base controller with integral burner control unit

The Logamatic BC25 base controller (Æ Fig. 38, pos. 1) is the standard programming unit of the GB172 gas condensing boilers with the Logamatic EMS control system. The Logamatic BC25 contains all required elements to make all standard settings on the heating system.

In addition, the Logamatic BC25 base controller offers a slot for the RC35 programming unit, which makes further functions available for convenient control.

4 Heating controls

Fig. 38 Logamatic BC25 base controller with clipped-in RC35 programming unit

1 Logamatic BC25 base controller 2 RC35 programming unit (Æ page 48)

6 720 641 280-13.1il

reset

Fig. 39 Display, indicators and controls on the Logamatic BC25 base controller

1 Diagnostic interface 2 “DHW” key 3 “Central heating” key 4 Display (Æ Fig. 40) 5 “-” key 6 “+” key 7 “OK” key

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

8 “Back” key 9 Pressure gauge 10 ON/OFF switch 11 “Summer/Winter” mode key 12 “Reset” key 13 “Service” key 14 Slot for RC35

6 720 641 280-12.1il

Page 46

4 Heating controls

2 3 4 876 95

13 121415

6 720 619 605-12.1O

Fig. 40 Logamatic BC25 display

1 No DHW mode 2 DHW mode 3 Solar mode 4 Weather-compensated mode

(control system with outside temperature sensor)

5 Emissions test mode 6 Fault (combined with key 7: service mode) 7 Service mode (combined with key 6: service mode) 8 Burner operation 9 Temperature unit °C 10 Saved successfully 11 Display of further submenus/service functions;

scroll with + and – keys

12 Alphanumeric display (e.g. temperature) 13 Text line 14 No heating mode 15 Heating Mode

Functions and controls on the Logamatic BC25 base controller

• Microprocessor-controlled digital monitoring and control of all electronic components of the appliance via the integral burner control unit

• ON/OFF switch for starting and shutting down the boiler and all connected modules (Æ Fig. 39, pos. 11)

• Starting and stopping heating mode

• Setting the maximum boiler flow temperature for heating mode (between 30 °C and 82 °C)

• Starting and stopping DHW mode and DHW circulation

• Selecting the set DHW temperature (maximum 60 °C)

• Thermal disinfection either controlled by the RC35 programming unit (automatic start in regular intervals) or by the BC25 base controller (manual start)

• DHW temperature setting – appliances with DHW cylinder

–DHW mode

The DHW cylinder is reheated up to the selected temperature when the temperature inside the DHW cylinder drops by more than 5 K (°C) below the selected temperature. The appliance then enters heating mode.

– Economy mode

The DHW cylinder is reheated up to the selected temperature when the temperature inside the DHW cylinder drops by more than 10 K (°C) below the selected temperature. The appliance then enters heating mode.

• DHW temperature setting – GB172-24 K (appliance with integral plate heat exchanger for DHW heating according to the instantaneous water heater principle)

–DHW mode

The appliance is permanently kept at the selected temperature. Consequently, DHW draw-offs are not subject to long delays. The appliance still starts even if no DHW is being drawn off.

– Economy mode

The cylinder contents are only heated to the selected temperature if DHW is being drawn off.

• DHW circulation pump

• “Summer/Winter mode” changeover key (Æ Fig. 39, pos. 12)

• Frost protection

•Manual mode

• Every time the pump is switched off, a timer starts to briefly switch on the heating circuit pump and the 3-way valve at regular intervals (anti-seizing protection).

• Where a low loss header is required, the low loss header sensor can be installed either at the boiler (BC25) or via a WM10 module. Use the version with an additional WM10 if there is a heating circuit without mixer (can be regulated via a WM10) or if four heating circuits are required (3x MM10 modules, 1x WM10 module)

• The venting function can be activated after servicing by means of the venting program.

• The siphon fill program ensures that the condensate siphon is filled following installation or after the appliance has been out of use for some time.

• Display of current set and actual boiler values (monitoring function)

• Boiler relay test

• Emissions test function (flue gas test)

• Central heating delay to enable DHW heating (solar mode, for the GB172-24 K)

• Selecting the set DHW value

•DHW priority

• Service interval (in months)

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4.4.2 RC25 programming unit

The RC25 (Æ Fig. 41) programming unit is connected to the Logamatic EMS and supplied with power via a 2-core BUS cable. It may be used either as a base controller or as a remote control. A wall mounting bracket for securing the RC25 programming unit inside the living space is part of the standard delivery.

7 747 009 801-19.1il

Fig. 41 Displays and controls of the RC25

programming unit

1 LCD for showing the selected values and temperatures

(permanent display: actual room temperature)

2 Rotary selector for adjusting values that are shown after

pressing a key in the display or for switching between the service level menus

3 Operating mode selector key with LED for automatic

heating mode in accordance with a time switch

4 Operating mode selector key with LED for standard

heating mode (day mode - “Constant heating”)

5 Operating mode selector key with LED for setback

heating mode (night mode – “Constant setback”)

6 Key with LED for activating once only DHW heating or for

selecting the DHW temperature

7 Flap to cover the second control level 8 Key for selecting the heating program 9 Key for adjusting the time and the day of the week

4 Heating controls

In both applications, the LCD indicates the captured room temperature (Æ page 41, pos. 1). The LCD also shows the time and the day of the week.

Selector keys (Æ Fig. 41, pos. 3 to 5) enable the selection of the heating operation modes “Automatic”, “Constant heating” and “Constant setback”. The integral LED signals the current operating mode.

The functions of the RC25 programming unit are accessible at two operating levels that are called up in accordance with the simple and proven “Push & Turn” operating concept. If required, a calibration function for the room temperature is available at the service level; this is activated via a recessed key in the side of the unit. Heating contractors can set various system parameters at the service level, e.g. activating DHW heating with permanent control of a DHW circulation pump, or defining the thermal disinfection function.

4.4.3 Wireless RC20 RF programming unit with

RFM20 wireless module

The RC20 RF wireless programming unit offers the same functions as the RC25 programming unit (Æ Fig. 41). Wireless communication between the RC20 RF wireless programming unit installed in the living area and the Logamatic EMS control system installed in the cellar requires the RFM20 wireless module (Æ Fig. 42). To achieve the best possible wireless reception, we recommend installing the module on the wall immediately next to the EMS control system.

A system with room temperature-dependent control of a downstream heating circuit without mixer can only be achieved with the RC25 programming unit. The room temperature sensor is integrated into the RC25. In addition, the RC25 programming unit can regulate a DHW circuit with thermal disinfection and DHW circulation pump, as well as a 7-day time switch with standard programs.

If the RC25 programming unit acts as a remote control, then the RC35 programming unit takes over control of the heating circuits and the gas condensing boiler in the Logamatic EMS control system. In that case, the RC25 programming unit supplies the necessary information from the room and regarding the operating mode.

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7 747 009 801-20.1il

Fig. 42 Displays, indicators and controls of the RFM20

wireless module (shown with the RC20 RF wireless programming unit)

1 LED indicators for the heating circuit channel 2 Key with LED “Learn function of the RC20 RF” 3 Terminal cover 4 “Heating circuit channel selection” key

Page 48

4 Heating controls

The RFM20 wireless module is required only once per EMS control system for the control of up to three heating circuits. Communication and power supply of the module are provided by a 2-core BUS cable from the control system. Transmissions occur at 1-minute intervals at a transmission strength of 10 mW and a duration of 150 ms, which is comparable to a mobile phone.

4.4.4 RC35 programming unit

The RC35 programming unit (Æ Fig. 43) is connected to the Logamatic EMS control system and is supplied with power via a 2-core BUS cable. The RC35 programming unit can either be clipped into the Logamatic BC25 base controller in the boiler or installed on a wall mounting bracket inside the living space. Installed in the living space, the programming unit RC35 is also suitable as a convenient room temperature-dependent controller. The RC35 programming unit must be software version 1.15 or higher in order to guarantee full compatibility.

7 747 009 801-18.1il

Fig. 43 Displays, indicators and controls of the RC35

programming unit

1 LCD for showing the selected values and temperatures

(permanent display: actual room temperature)

2 Rotary selector for adjusting values that are shown after

pressing a key in the display or for switching between the service level menus

3 Operating mode selector key with LED for automatic

heating mode in accordance with a time switch (automatic changeover between day and night room temperature)

4 Operating mode selector key with LED for standard

heating mode (day mode - “Constant heating”) summer mode interruption

5 Operating mode selector key with LED for setback

heating mode (night mode “Constant setback”)

6 Key with LED for activating once only DHW heating or for

selecting the DHW temperature

7 Flap to cover the second control level 8 Key for changing menus or control levels 9 Key for info menu (scanning values) 10 Key for adjusting the room temperature 11 Key for adjusting the day of the week 12 Key for adjusting the time 13 Key for the control menu

With the RC35 programming unit in its standard version, one heating circuit without mixer can be controlled in the operating modes room temperature-dependent, weather-compensated or weather-compensated with room temperature hook-up. For room temperature-dependent control or for room temperature hook-up, install the RC35 programming unit in the reference room. If the reference room is not the location where the RC35 programming unit is installed, an external room temperature sensor can be connected at the unit's wall mounting base.

The RC35 programming unit is equipped with a programmable 6-channel digital time switch with eight standard programs for the graphic display of the switching cycles and the outside temperature (with integral “Weather station”). Individual programs can also be created for each heating circuit in conjunction with the Logamatic EMS control system and/or the MM10 module. An individual time channel is available for DHW heating including control of a DHW circulation pump. The standard functions also include thermal disinfection, which can be adjusted as required, and once only DHW heating. All important information regarding the heating system, including fault displays, room temperature, time and day of the week can be captured with the RC35 programming unit and displayed “in plain text” on the backlit LCD with graphic capabilities (Æ Fig 43, pos. 1).

Selector keys (Æ Fig. 43, pos. 3 to 5) enable the selection of the heating operation modes “Automatic, Constant heating” and “Constant setback”. The integral LED signals the current operating mode.

The Logamatic EMS control system, together with the RC35, regulates the low loss header and three additional heating circuits in conjunction with the MM10 mixer modules as well as the solar DHW heating in conjunction with the SM10 solar module (system example Æ page 90).

The RC35 programming unit also includes some special functions, e.g. a “Holiday function” for the entire system or, in conjunction with the MM10 module, for each individual heating circuit.

In addition, several service functions can be used, e.g. “Monitor function”, “Function test”, “LCD test”, “Fault monitoring”, “Fault indication”, “Scanning the heating curve”.

The functions of the RC35 programming unit are accessible at several levels that are called up in accordance with the simple and proven “Push & Turn” concept. There are two control levels for users, segregated into standard functions and extended functions. At the service level, contractors can make adjustments, e.g. for the heating circuits or DHW heating.

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4.5 Function modules for extending the Logamatic EMS control system

4.5.1 Modules for Logamax plus GB172/GB172T

All delivered modules are equipped with a BUS cable, mains plug and a wall mounting base (including rawl plugs and screws). This enables a straight-forward installation outside the boiler.

Quick installation sets for heating circuits without integral modules

The following heating circuit quick installation sets including high efficiency pump, efficiency category A, are available:

• Quick installation sets for heating circuits with mixer – HSM 15 E-plus – HSM 20 E-plus – HSM 25 E-plus – HSM 32 E-plus

• Quick installation sets for heating circuits without mixer – HS 25 E-plus – HS 32 E-plus

Fig. 44 Function module for wall mounting mode

1 Terminal cover 2 Base module 3 Wall mounting bracket with strain relief for connecting

cables

4 Heating controls

7 747 009 801-21.1il

Quick installation sets for heating circuits with integral modules

The following heating circuit quick installation sets with integral modules are available:

• Quick installation sets for heating circuits with low loss header module

– HS 25 E-plus (EMS Inside) – HS 32 E-plus (EMS Inside)

• Quick installation sets for heating circuits with mixer module

– HSM 15 E-plus (EMS Inside) – HSM 20 E-plus (EMS Inside) – HSM 25 E-plus (EMS Inside) – HSM 32 E-plus (EMS Inside)

The modules are prewired at the factory. For commissioning, the modules must be connected to a 230 V power supply.

6 720 642 463-26.1il

Fig. 45 Heating circuit quick installation set with

high efficiency pump, efficiency category A (with integral EMS module)

4.5.2 ASM10 connection module

The ASM10 connection module is a BUS distributor that represents an extension of the EMS-BUS with several subscribers, e.g. MM10 mixer module or RC25/RC20 RF programming unit, to which six BUS subscribers can be connected. It is used in the Logamatic EMS control system and is wall mounted.

The module also features the following:

• 1 EMS-BUS input and 5 EMS-BUS outputs

• Encoded and colour-coded connection plugs

• Internal communication via EMS databus

• Wall mounting base into which the EMS system module is clipped

• Strain relief for all connecting cables

• Terminal cover

• Module IP rating inside the wall mounting set: IP 40

• Including installation materials

• Number of modules per system subject to demand

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4 Heating controls

4.5.3 MM10 mixer module

The MM10 mixer module extends the Logamatic EMS control system by heating circuits with mixer. Up to three modules can be used with the RC35 programming unit. It can only be used if the gas condensing boiler is hydraulically separated by means of a low loss header and one heating circuit distributor for two heating circuits (system example Æ page 88). For heating circuits 2, 3 and 4, the heating systems “Radiator”, “Convector” or “Underfloor” can be selected at the service level of the RC35 programming unit. These circuits can be operated in weather-compensated or in room temperature-dependent mode. If the “Underfloor” heating system has been selected for the heating circuits, the “Screed drying” function can also be regulated. In addition, these heating circuits can be operated purely under room control.

A programming unit is required in the reference room if a heating circuit is regulated in room temperature-dependent mode (Æ Fig. 36, page 44). It may be directly connected to the MM10 mixer module. In this case, the RC35 or RC25/RC20 RF programming unit acts as a remote control.

4.5.4 SM10 solar module

The SM10 solar module enables the integration of solar DHW heating into the Logamatic EMS control system (system example Æ page 90).

4.5.5 WM10 low loss header module

The WM10 low loss header module regulates the hydraulic separation between the boiler and the consumer circuits. This hydraulic separation can be achieved with a low loss header or via a heat exchanger. In addition, the WM10 low loss header module can actuate the secondary pump for the heating circuit without mixer (heating circuit 1) (system examples Æ chapter 6.4.4, page 88 f.).

In systems with Logamax plus GB172/GB172T gas condensing boilers, hydraulic separation is generally required if two heating circuits with individual pumps are to be connected.

Provide a mixer module for every heating circuit if only heating circuits with mixers are used in the heating system (e.g. system example Æ 6.4.3, page 86 f.). In that case, no low loss header module is required. The low loss header module can be connected directly to the Logamatic BC25. However, if there is one heating circuit without mixer, the heating circuit pump of that circuit can be switched by means of the auxiliary function of the low loss header module. In that case, the low loss header sensor is connected to the low loss header module.

The SM10 solar module not only offers a temperature differential control, it also includes a function that enables the control of the solar circuit pump to deliver a variable flow rate. This High-Flow/Low-Flow operation enables demand-optimised DHW heating. When the system is still cold, the system initially produces DHW quickly from the solar yield for “optimum convenience.” When sufficient hot water is available, the system switches over to “yield optimisation”.

In addition, the SM10 solar module includes a function to optimise reheating. This clearly highlights the intelligent linking of boiler and solar control unit. This control function suppresses reheating by the gas condensing boiler, subject to the heat input capacity of the DHW cylinder if the solar yield is adequate. This allows an optimisation of the solar yield and up to 10 % primary energy can be saved.

To enable solar DHW heating, the heating circuit “Solar thermal system” should be selected at the service level of the RC35 programming unit.

7 747 009 801-23.1il

Fig. 46 Low loss header module WM10 (base module)

1 Base module 2 Appliance fuse 3 Access to the spare fuse 4 LED operating and fault displays 5 Plug-in strip for control voltage 6 Plugs for additional components in the Logamatic EMS

via EMS-BUS

7 Plugs for RC... programming unit 8 Plug for the flow temperature sensor

(here temperature sensor for low loss header)

9 Plug-in strip for mains voltage 10 Plug for heating circuit pump 11 Slot for the power supply of additional function modules

(mains output)

12 Plug for 230 V AC, 50 Hz power supply

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4 Heating controls

4.5.6 Logamatic web KM200 communication module

The web KM200 communication module is used as an interface between the heating system and a network (LAN). It enables the operation and remote monitoring of the heating system via iPhone, iPod touch or iPad.

• Intuitive operation of the heating system by means of

the EasyControl App in a local WLAN network and via the internet

• Checking and changing system parameters

(e.g. operating mode changeover, set temperatures for day and night, time switches for all heating circuits) and the configuration of the web KM200 communication module

• Compatible with iPhone, iPod touch or iPad

• Display of fault and service messages in the App

• Easy module installation through Plug & Work

• Security through password protection

Standard delivery:

•Wall mounted module

• 230 V power supply

• Technical documentation

System requirements

• Programming unit series RC... manufactured from

2003 with EMS-BUS interface, e.g. RC25

• All modules in the RC...series manufactured from 2003

e.g. MM10

• Heat source with EMS-BUS interface

• iOS version 3 or higher

• Existing LAN network (router). Additional costs may

arise for the internet connection. We recommend a flat rate internet connection.

4.5.7 Logamatic Easycom telecontrol modem

In the form of the Logamatic Easycom, Buderus offers an affordable telecontrol modem for remote monitoring and setting of parameters in small and medium-sized heating systems. It is available as the module version EM including programming software and cable.

The following are the essential features of the telecontrol modem:

• May be connected to any control unit of the Logamatic 2000, 4000 or EMS systems; with BUS-capability for the subscribers of a BUS system; with an additional potential-free message input

• Connection via an analogue telephone connection or, with an adaptor, via an ISDN system; high

• data transfer speed (56 kBit/s)

• Complete remote scanning and setting of parameters of the connected system via PC software Logamatic ECO-SOFT with operating mode changeover via telephone (holiday home function)

• Remote monitoring of the connected system with automatic fault message to any 3 selectable recipients; possible recipients are fax, mobile phones (SMS via D1, D2 or E-Plus), PC call centres (with PC software ECO MASTERSOFT) or email addresses

• Prepared for firmware updates via software download

Dimensions 151×184×61mm (W×H×D)

Rated voltages

BUS:12 V to 15 V DC (protected against polarity reversal)

Module: 230V AC/7.5 V DC, 700 mA)

Interfaces EMS-BUS

LAN: 10/100 MBit/s (RJ45)

IP rating IP20

Table 20

6 720 641 280-15.1il

Fig. 47 Logamatic Easycom telecontrol modem

(EM module version)

1 Operating mode selector (ON/OFF) 2 Standby display 3 “Message” display 4 “Telephone line busy” display 5 “Service” display 6 “Service” or “Restart” key 7 Terminal cover for EM module version

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4 Heating controls

4.5.8 EM10 fault message module

The EM10 fault message module can be used as an interface between the boiler and, for example, a building management system.

A 0–10 V DC signal enables control over the flow temperature or the output (Æ Fig. 48).

In combination with the Logamax plus GB172/GB172T, the EM10 fault message module provides two standard functions:

• Output of a fault indication with a 230 V signal (with potential) (buzzer, signal indicator, max. 1 A) and a floating contact for LV signals. A fault indication is generated under the following circumstances:

– The boiler has suffered a lockout fault – The water pressure in the system is too low – Communication with the boiler has been interrupted

for longer than five minutes

• Switching the boiler with an external 0-10 V DC signal. A flow temperature is specified to the boiler via the 0-10 V DC signal (Æ Fig. 48).

Only one of the two fundamental functions can be used.

(°C)

100

Control via the output

The EM10 module transmits the 0–10 V signal from the building management system to a set output. This is a linear ratio.

Input

voltage

in V

Set flow

temperature point

(boiler) in °C

Boiler state

0 0OUT

0.5 0 OUT

0.6 ± 6Low load

5 ± 50 Partial load

10 ± 100 Full load

Table 22 Control via the output

1) The output at low load depends on the appliance type. If the low load of the appliance is, for example, 20 % and the control signal 1 V (= 10 %), then the set output is lower than the low load. In that case, the appliance will deliver 10 % at low load through an ON/OFF cycle. In this example, the boiler enters constant operation from a set point of 2 V.

4.5.9 VM10 function module for an external

solenoid valve

0246810

7 747 009 801-24.1il

U (V)

Fig. 48 Curve, EM10 fault message module

(set values)

TVFlow temperature U Input voltage

Control via the flow temperature

The EM10 module transmits the 0–10 V signal from the building management system to a set flow temperature point. This is a linear ratio.

Input

voltage

in V

Set flow

temperature point

(boiler) in °C

Boiler state

0 0OUT

0.5 0 OUT

0.6 ± 15 ON 5 ± 50 ON

10 ± 90 ON/maximum

Table 21 Control via the flow temperature

7 747 009 801-25.1il

Fig. 49 VM10 function module

When combined with the Logamax plus GB172/GB172T, the VM10 function module takes over the switching and power supply of an external solenoid valve for the operation of appliances below ground level with LPG.

When the boiler receives a heat demand, the external solenoid valve is opened two seconds ahead of the gas valve of the appliance.

The external solenoid valve remains closed when there is no heat demand for the boiler. The external solenoid valve remains closed if the appliance has developed a fault.

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4.6 Selection aid for possible equipment levels using the components of the Logamatic EMS control system

Control components and their functions Logamax plus

GB172-24 K/

GB172

Boiler components

Logamatic BC25 base controller z z

RC25/RC20 RF programming unit

As weather-compensated control   As room temperature-dependent control  As a remote control in conjunction with the RC35 programming unit

RC35 programming unit

 

As weather-compensated control   As a room temperature-dependent control unit



Connection of an external room temperature sensor   As remote control Cylinder connection set AS-E



 z

Function modules



WM10 low loss header module  MM10 mixer module SM102)solar module

Logamatic Easycom telecontrol modem  Web KM 200 communication module 

Control system extension options

External interlock (floating contact) z z External heat demand (floating contact) zz External heat demand 0-10 V (EM10 fault message module)   Central fault message (EM10 fault message module)  Remote monitoring   Remote configuration  Second solenoid valve, e.g. for LPG (VM10 function module)  

Table 23 Selection aid for the possible equipment level of the Logamax plus GB172/GB172T with components of the

Logamatic EMS control system

1) As a remote control for heating circuit 1, if the RC35 programming unit is installed inside the boiler or as a remote control for heating circuit 2.

2) Part of the standard delivery of the GB172-14/20 T210SR

3) Only one RC35 programming unit per system: If the RC35 programming unit is installed in the boiler or a second heating circuit is planned,

then an additional RC25/RC20 RF programming unit per heating circuit as a remote control is required.

4) AS-E includes DHW temperature sensors for DHW heating with plugs and dummy segments.

5) Integral DHW temperature sensor, connected at the factory

6) In conjunction with the RC35 programming unit, three function modules can be used in each system.

7) The modules can only be installed outside the boiler on the GB172/GB172T models.

8) Function module for solar thermal systems for one consumer (solar DHW heating with yield optimisation). The SM10 solar module can only be

used once per system. SM10 is an integral part of the solar GB172-14/20 T210SR compact heating centres.

GB172T



z Standard equipment  Option

– Not possible

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4 Heating controls

4.7 Logamatic 4121 and 4122 control units

Logamatic 4121 control unit

The Logamatic 4121 control unit is part of the modular Logamatic 4000 control system. In its standard version, it includes the CM431 controller module, the MEC2 programming unit and the ZM424 central module. The Logamatic 4000 must be software version 8.720 or higher in order to guarantee full compatibility.

• Logamatic 4121 (part no. 7 747 011 916)

The following components can be controlled:

• One gas condensing boiler with modulating burner operation

• One heating circuit with actuator

• Selection function (only one function can be selected) – A second heating circuit without actuator and DHW

temperature control via a cylinder primary pump incl. switching the DHW circulation pump via the Logamatic 4000

– A second heating circuit with actuator and DHW

temperature control via EMS (with 3-way diverter valve) or cylinder primary pump and DHW circulation pump

Logamatic 4122 control unit

In its standard version, the Logamatic 4122 control unit includes only the CM431 controller module and the MEC2 programming unit (Æ Fig. 51). Some functions are not included. The functionality of the control unit is dictated by the various modules (Æ Table 24).

• Logamatic 4122 with MEC2 (part no. 7 747 011 918)

• Logamatic 4122 with display (part no. 7 747 011 922)

The following are alternative applications:

• Logamatic 4122 combined with the function modules FM441, FM442, FM443, FM444, FM445, FM446 and FM448 to extend the control functions (up to 56 heating circuits)

1,2

6 720 641 280-16.1il

Fig. 50 Logamatic 4121 control unit with standard

equipment level

1 Central module ZM424 2 CM431 controller module 3 MEC2 programming unit 4 Control unit ON/OFF switch 5 Fuse

2,3

6 720 641 280-17.1il

Fig. 51 Logamatic 4122 control unit as standard

version with MEC2 programming unit; as an option with a display

1 CM431 controller module 2 MEC2 programming unit 3 Control unit ON/OFF switch 4 Fuse

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Control options, Logamatic 4122 control unit

Possible function

Control unit Slots

modules

4 Heating controls

Control options

Logamatic 4121

(master device)

Logamatic 4122

(extension for

master device)

ZM424 (standard

equipment level)

FM442 Heating circuits 3 and 4

FM443 Solar thermal system with one or two consumers

FM444

FM445

FM446 EIB interface (European Installation BUS)

FM448 Central fault message

FM456 KSE2

(FM457 KSE4)

FM441 1 additional heating circuit, DHW heating

FM442

FM443 Solar thermal system with one or two consumers

(alternative to the FM441)

FM445

FM446 EIB interface (European Installation BUS)

Heating circuits 1 and 2, DHW heating, boiler

Module for connecting an alternative heat source or buffer cylinder

DHW heating via the cylinder primary system with external heat exchanger

Not currently possible in combination with the GB172/GB172T

2 additional heating circuits (up to 56 heating circuits with 14 Logamatic 4122 substations)

DHW heating via the cylinder primary system with external heat exchanger

FM448 Central fault message

FM456 KSE2

(FM457 KSE4)

Not currently possible in combination with the GB172/GB172T

FM441 Heating circuit 1, DHW heating

FM442 Heating circuits 1 and 2

FM443 Solar thermal system with one or two consumers

Logamatic 4122

(master device)

FM445

(alternative to the FM441)

DHW heating via the cylinder primary system with external heat exchanger

FM446 EIB interface (European Installation BUS)

FM448 Central fault message

FM456 KSE2

(FM457 KSE4)

Not currently possible in combination with the GB172/GB172T

Table 24 Control and extension options for the Logamatic 4121 and 4122 control units

1) When using the FM445 function module, DHW heating through the ZM424 central module will be disabled.

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Communication-enabled MEC2 programming unit

All important parameters of the Logamatic 4121 and 4122 control units are managed by the digital MEC2 programming unit (Æ Fig. 52). The control concept is based on the easy and proven “Push & Turn” principle. For this, the user prompts prevent contradictory settings of parameters, thereby largely preventing faults during commissioning. All available information can be displayed in “plain text”. One room temperature sensor and a radio clock receiver are integrated as standard.

≥ 1,50

≥ 0,75

MEC2

≥ 0,6

≥ 1

The MEC2 programming unit can be located either at the control unit, in an online set at the boiler casing or with the room installation set in the living space. A simple 2-core cable connects the wall mounting bracket of the room installation set with the Logamatic 4121 or 4122 control unit.

If the MEC2 programming unit with the room installation set functions as a remote control in the living area, use a boiler display unit inside the control unit in its place. In that case, this operating display shows the system flow.

• Room installation set with wall mounting bracket and boiler display (part no. 5 720 812)

For further details, see the technical guide concerning the “Modular Logamatic 4000 control system”.

6 720 641 280-19.1il

Fig. 53 Position of the wall mounting bracket for the

MEC2 programming unit in the reference room (dim. in mm)

1 Required clearance below the MEC2

–

6 720 641 280-18.1il

Fig. 52 MEC2 programming unit with integral room

temperature sensor and wall mounting bracket

1 MEC2 programming unit including integral room

temperature sensor and radio clock receiver

2 Wall mounting bracket for the MEC programming unit

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5.1 Selection aids for selecting integral or separate DHW heating

Gas condensing boilers have very high efficiency. Therefore, heating DHW with the Logamax plus GB172/GB172T is recommended, both from an energy consumption and an ecological viewpoint. Individual demands can also be met with the GB172/GB172T gas condensing boilers. This boiler type is suitable both for integral direct DHW heating (GB172-24 combi boiler, Æ page 58) as well as for a combination with separate DHW cylinders (GB172, selection aids Æ page 59 f) or as a GB172T compact heating centre.

When planning heating systems and making a decision on integral or separate DHW heating, various factors should be taken into account:

• Simultaneous use of different draw-off points

• DHW demand and convenience

• Line length (with or without DHW circulation line)

• Availability of space

•Costs

• Replacement of system components

5 DHW heating

Planning criteria

Use of the draw-off points

DHW demand

Line length

Availability of space

Costs Affordable solution z + + z

Replacement

Possible versions Logamax plus

GB172 with separate DHW cylinder

Only one main draw-off point z + + z Several main draw-off points,

but not simultaneously Several main draw-off points

simultaneously Single person household

(central DHW heating for one

residential unit) Four-person household

(central DHW heating for one residential unit or one detached house)

Many users (central DHW heating for an apartment building)

Up to eight metres (without DHW circulation line)

In excess of eight metres (with DHW circulation line)

Small –/z Medium z + + + Generous + + + +

Combi boiler available + + + – Cylinder available + – – +

+ + + +

+ – z +

z + + z

+ z z +

+ – – +

+ + + +

+ – + +

GB172-24 K

combi boiler

+ + z

GB172-24 T50

with integral

DHW cylinder

GB172T

compact

heating centre

Table 25 Selection aids for the selection of integral or separate DHW heating

1) In the case of adequate room height, recommended with the Logalux H65 W wall mounted DHW cylinder (below or adjacent) or Logalux WU120 W, WU160 W or S120 W (floor standing below)

+ Recommended z Limited recommendation – Not recommended

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5 DHW heating

5.2 Application limits Stratification cylinder with the GB172-20 T100S, GB172-14/24 T150S and GB172-14/20 T210SR

At a total hardness of the potable water of 15 °dH to 20 °dH, we recommend that the cylinder temperature is set to ≤ 55 °C. In the case of a dual-mode solar stratification cylinder, also limit the cylinder temperature at the solar controller to 55 °C. As an alternative, a water treatment system can also be used.

From an overall hardness level of 21 °dH upwards, a dislodging of scale inside the plate heat exchanger must be expected. We recommend either the use of a cylinder with internal indirect coil or, as an alternative, the use of a water treatment system.

5.3 Integral DHW heating with a plate heat exchanger in the Logamax plus GB172-24 K

Suitable for

• Several draw-off points that are not used

simultaneously

• Small number of users

• DHW lines shorter than 8 m

• Total water harness below 21° dH

• Copper DHW pipework

Connected DHW lines must be made from material that is compatible with copper.

Function

• Immediate availability of DHW without delay through

hot start option in summer mode

• Temperature maintaining function with adjustable

DHW outlet temperature between 40 °C and 60 °C (Æ Fig. 56) in summer mode

• Adjustable cold start function for hard water areas or

for maximum energy savings

• Maximum DHW draw-off rate of 7.9 l/min at a DHW

outlet temperature of 60 °C

• DHW priority mode with the aid of a powerful heat

exchanger in accordance with the instantaneous water heater principle (Æ Fig. 54)

• Control of the DHW outlet temperature

• DHW draw-off rate defined via flow rate limiter (9 l/min)

• High constant DHW output (Æ Fig. 55) of 29.7 kW

[°C]

6 7 8 9 10 11 12 13

[l/min]

6 720 641 280-22.1il

Fig. 55 Constant DHW output at a cold water inlet

temperature of 10 °C

ϑwwDHW outlet temperature

VwwDHW flow rate

ϑ / °C

6 720 641 280-21.2O

100 150

200

250 300

350 t / s

6 720 641 280-20.1il

Fig. 54 Integral plate heat exchanger according to the

instantaneous water heater principle

AW DHW outlet EK Cold water inlet RS Cylinder return VS Cylinder flow 1 Flow temperature sensor 2 Flow sensor 3 Flow limiter 9 l/min 4 DHW temperature sensor

Fig. 56 DHW outlet temperature and DHW

temperature maintaining level subject to the setting at the BC25 controller

ϑ DHW temperature

t Time a Hot start at 60 °C DHW outlet temperature b Hot start at 45 °C DHW outlet temperature c ECO with 60 °C DHW outlet temperature d Cold water inlet temperature

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 59

5.4 Selection of a suitable DHW cylinder

The size of the required DHW cylinder depends on the DHW demand. The following selection takes into account residential units with up to three or four occupants.

5 DHW heating

148 l capacity or a dual mode solar stratification cylinder with 204 l capacity is already integrated into the Logamax plus GB172T.

A DHW cylinder with internal indirect coil and 48 l, 115 l or 143 l capacity, one stratification cylinder with 101 l or

Draw-off point Bath tub 200 l Bath 140 l

(10 min)

Bath tub 200 l

Bath 140 l (10 min)

Bath 160 l (10 min)

SU200 W

SU160 W

WU160 W

1) 1)

S120 W/

WU120 W

Bath 160 l (10 min)

SU160 W/ WU160 W

S120 W/

WU120 W

Separate DHW cylinders with the same functions can be connected to the Logamax plus GB172.

Economy shower (6 min, 40 l)

SU200 W SU200 W SU200 W

SU160 W/

WU160 W

SU160 W/

WU160 W

Standard shower (6 min, 90 l)

SU200 W

Basin (3 min, 18 l)

S120 W/

WU120 W

SU160 W/ WU160 W

Economy shower (6 min, 40 l)

Standard shower (6 min, 90 l)

Basin (3 min, 18 l)

SU200 W

SU160 W/ WU160 W

SU160 W/

WU160 W

SU160 W/

WU160 W

S120 W/

WU120 W

Table 26 Selection of a suitable DHW cylinder

1) Unusual combination

Suitable for ≥ 20 kW boiler output

Suitable for ≤ 14 kW boiler output

Suitable for both boiler output ranges

Table 27 Explanation of the colour coding in table 26

SU160 W/ WU160 W

SU200 W

SU160 W/ WU160 W

H65 W

H65 W/

T50

T50/

S120 W/

WU120 W

H65 W

T50

S120 W/

WU120 W

S120 W/

WU120 W

S120 W/

WU120 W

H65 W

S120 W/

WU120 W

H65 W

T50

General conditions:

• Cylinder temperature 60 °C.

• Only one consumer is taken into consideration in the case of two identical consumers.

• If dual mode cylinders are used, take their standby volume into account.

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5 DHW heating

5.5 DHW circulation line for DHW cylinder

Every DHW circulation line is a heat consumer. Long, poorly designed or insufficiently insulated pipework can result in substantial heat losses. Therefore, short DHW lines without DHW circulation lines should be installed.

However, if a DHW line length is longer than approx. eight metres, the connection of a DHW circulation line is recommended.

Where a DHW circulation line cannot be avoided, observe the following rules:

• The DHW circulation connection can be installed in the cold water inlet of the Logalux S120 W DHW cylinders.

• Minimise the amount of circulating water. This requires a pressure drop calculation for the pipework or sizing of the pump. Temperature differentials from 5 K between the DHW outlet and the DHW circulation inlet must be reduced.

• EnEV [Germany] specifies the use of conventional timers or other automatic devices for shutting down the DHW circulation pump. The RC35 programming unit within the Energy Management System (EMS) provides its own time channel for DHW heating. Consequently, the DHW circulation pump can also be programmed for different operating modes.

It is generally adequate if the DHW circulation pump is operated for approx. three minutes in the morning, midday and in the evening.

Logalux

SU…W

6 720 646 236-23.1il

Fig. 58 Version of a DHW circulation line for the

Logalux SU...W DHW cylinder

KR Logamax plus GB172-24 T50

Logalux

S120 W

6 720 646 236-22.1il

Fig. 57 Version of a DHW circulation line for the

Logalux S120 W DHW cylinder

Key to Fig. 57 to Fig. 60: AW DHW outlet

EK Cold water inlet EL Drain EZ DHW circulation inlet KR Check valve PZ DHW circulation pump

6 720 646 236-03.1il

Fig. 59 Version of a DHW circulation line for a DHW

cylinder with internal indirect coils inside the Logamax plus GB172-24 T50

Logamax plus

GB172-.. T...

6 720 648 096-02.1O

Fig. 60 Version of a DHW circulation line for a DHW

cylinder inside the Logamax plus GB172T

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6 System examples

6.1 Information regarding all system examples

The system examples in this chapter provide information regarding the standard systems that are feasible with the Logamatic EMS control system. All systems that go beyond this configuration are currently not compatible with Logamax plus GB172/GB172T gas condensing boilers controlled by the Logamatic EMS.

The practical implementation is subject to currently applicable technical rules. Install safety equipment in accordance with local regulations.

6 System examples

RC25/RC20 RF

RC35

THV

GAS

SMF

Logamax plus

GB172 Kombi

GAS

SMF

Logamax plus

GB172

6 720 646 236-05.1il

Fig. 61 Hydraulics for the Logamax plus GB172-24 K (combi boiler) and the GB172-14/20/24

(technical information

FS Safety temperature sensor GAS Gas connection SMF Dirt filter THV Thermostatic valve

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

12 l expansion vessel (factory-fitted on the GB172-24 K)

Table 28, page 64 f.)

Page 62

6 System examples

THV

3)4)

GAS

SMF

Logamax plus GB172 T50

Fig. 62 Hydraulics of the Logamax plus

GB172-24 T50 (technical information

FR Cylinder return temperature sensor FS Safety temperature sensor FW DHW temperature sensor GAS Gas connection SMF Dirt filter PZ DHW circulation pump

DHW expansion vessel (accessory) 12 l central heating expansion vessel (factory-fitted on the GB172 T50 K) Cold water inlet (not shown) Cylinder flow (not shown)

Table 28, page 64 f.)

6 720 646 236-09.1il

THV

SMF

GAS

Logamax plus

GB172-.. T210SR

Fig. 63 Hydraulics of the Logamax plus

GB172-14/20 T210SR (technical information

FR Cylinder return temperature sensor FS Safety temperature sensor FW DHW temperature sensor GAS Gas connection SMF Dirt filter PZ DHW circulation pump

DHW expansion vessel (accessory) 12 l central heating expansion vessel (part of the standard delivery of the GB172-14/20 T210SR) Cold water inlet (not shown) Cylinder flow (not shown)

Table 28, page 64 f.)

6720648096-05.1O

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6 System examples

SMF

RC25/RC20 RF

RC35

THV

GAS

SMF

THV

GAS

RC25/RC20 RF

RC35

Logamax plus

GB172-.. T...

Logamax plus

GB172-.. T...S

6720648096-04.1O

Fig. 64 Hydraulics of the Logamax plus GB172-14 T120, GB172-14/20 T150 and Logamax plus GB172-20 T100S,

GB172-14/24 T150S (technical information

FR Cylinder return temperature sensor FS Safety temperature sensor FW DHW temperature sensor GAS Gas connection SMF Dirt filter PZ DHW circulation pump

DHW expansion vessel (accessory) 18 l central heating expansion vessel (part of the standard delivery) Cold water inlet (not shown) Cylinder flow (not shown)

Table 28, page 64 f.)

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6 System examples

Pos. General design information on hydraulics and control

Observe all building regulations applicable to installation rooms (DVGW-TRGI 2008 [Germany]). Make the gas connection in line with the technical rules applicable to gas installations. Take any DHW booster heating functions of the appliances into account when sizing the gas flow limiter. The gas

connection must only be made by authorised gas fitters. In addition, the installation of a gas filter to DIN 3386 in the gas line is also recommended.

Operation in occupied rooms is possible with an air/flue gas system or, under certain conditions, with

the concentric open flue system GA-X.

When draining condensate, observe all relevant local waste water ordinances. Frequently installations

follow the ATV-DVWK A251 [Germany].

Only operate the Logamax plus GB172/GB172T gas condensing boilers in sealed unvented heating

systems. Convert open vented systems in accordance with DIN-EN 12828.

Seal the connections at the cylinder flow (VS) and cylinder return (RS) if no separate DHW cylinder is

connected to the Logamax plus GB172/GB172T gas condensing boilers.

Extremely hard drinking water (high lime content) can result in increased maintenance requirements on combi boilers. From an overall hardness level of 21° dH upwards, it is therefore recommended to allow for separate DHW cylinders with internal indirect coils (e.g. model GB172-24 T50) or for a softening system for potable water.

The Logamax plus GB172-24 K as well as the GB172-20 T100S and GB172-14/24 T150S appliances feature DHW lines or heat exchangers made from copper. To prevent corrosion damage, only use connection lines and fittings that are compatible with copper. Implement the installation in accordance with DIN 1988 and DIN 4753 (as well as DIN-EN 1717) [or local regulations]. Observe

any ordinances concerning potable water. The GB172-24 T50 as well as the GB172-14 T120 and GB172-14/20 T150 appliances include drinking water lines made from stainless steel, whilst the internal drinking water pipework is implemented free from copper. Consequently, water pipework made from zinc-plated/galvanised pipes may also be connected.

Further

information

Page 42

Page 119 ff.

Page 119

Page 120 f.

Page 94

Page 42

Page 66

When connecting the Logamax plus GB172 to plastic cold water or DHW lines, observe the methods of connection with other materials recommended by the manufacturer of the plastic pipes.

48 l cylinder with internal indirect coil (integrated in the GB172-24 T50) with Thermoglaze as

corrosion protection plus integral magnesium anode

An extensive range of accessories is available for all Logamax plus GB172/GB172T gas condensing boilers. There are suitable pipe assemblies to connect the Logamax plus GB172 gas condensing

boilers with the Logalux S120 W, Logalux SU160 W to SU300 W, Logalux H65 W as well as the Logalux WU120 W and WU160 W DHW cylinders.

For room temperature-dependent or weather-compensated control with room temperature hook-up, install a room temperature sensor in the reference room of the residential unit. The room temperature

sensor is part of the RC35 and RC25/RC20 RF programming unit. Open thermostatic radiator valves fully in the reference room.

A low water indicator is not required when installing the Logamax plus GB172/GB172T gas condensing boilers as attic heating centres. The function of a thermostatically controlled low water

indicator is safeguarded with a temperature sensor inside the appliance and is verified through type testing in accordance with DIN-EN 12828.

A dirt trap is not required if a new system is thoroughly flushed prior to commissioning (loose

particles), as a result of which oxygen corrosion can be prevented. Older systems must always be flushed; the installation of a dirt trap is also highly recommended.

A drain & fill valve (DFV) is integrated in the Logamax plus GB172/GB172T. It is generally

recommended to install a drain facility at the lowest point of the heating system.

Page 96 ff.

Page 44

Page 47

Page 48

Page 8 ff.

Page 66

Page 96 ff.

Table 28 Information on the sample circuit diagram (ÆFig. 61, page 61) for all systems with Logamax plus

GB172GB172T

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6 System examples

Pos. General design information on hydraulics and control

Design the discharge pipes from safety valves in accordance with DIN-EN 12828 so that any escaping heating water can be drained off safely. The required drain outlet with siphon is available as a connection accessory.

The discharge pipes from safety valves of separate DHW cylinders must also be connected with the sewer system via a drain outlet with siphon.

Check the sizing of the expansion vessel in accordance with DIN 4807-2 and DIN-EN 12828. If the expansion vessels sized for standard solutions is insufficient, install an appropriately sized expansion

vessel on site.

The transferable output in conjunction with an underfloor heating system directly downstream is restricted for the Logamax plus GB172/GB172T gas condensing boilers. When transferring greater outputs, allow for a low loss header with flow temperature sensor. Underfloor heating systems with

pipes that are permeable to oxygen require system separation. Weather-compensated control is recommended in conjunction with underfloor heating systems due to the inertia during heat-up.

The power supply must be 230 V AC, 50 Hz. Install an isolator in the power cable (MCB 10 A, type B with at least 3 mm contact separation). The power supply connection must only be made by an authorised electrician. For electrical installations, observe all relevant local and national regulations (e.g. VDE in Germany) plus those specified by your local power supply utility.

The GB172/GB172T is equipped with a 1.5 m long power cable with plug. It can be connected to a standard socket. A permanent electrical connection is also possible after removing the power supply cable from the terminal strip.

Further

information

Page 37 ff.

Page 96 ff.

Page 70

Page 67

Page 88

Page 49 ff.

Page 88 ff.

The operation of the Logamatic EMS control system requires – apart from the principle operation via the Logamatic BC25 base controller – an RC25/RC20 RF or RC35 programming unit. The flexibility of the Logamatic EMS control system enables the arrangement of the RC35 programming unit either on the wall in the living space or in the boiler itself. If the RC35 programming unit is clipped into the boiler, an additional RC25/RC20 RF programming unit can be used as a remote control. Only one

RC35 programming unit can be used per system. It can be allocated to any heating circuit. As a remote control for another heating circuit (only feasible with the RC35 programming unit in conjunction with the MM10 mixer module), a further RC25/RC20 RF programming unit can be installed in the living space of the second heating circuit. One RC25/RC20 RF programming unit can be used per heating circuit, i.e. not more than two per system.

The RC35 programming unit can control further control components in conjunction with the additional function modules. The Logamatic EMS control system enables the wall mounting of the function modules near the respective pipe assembly. Alternatively, heating circuit quick installation sets with integral EMS modules (EMS Inside) can be used. For more complex hydraulic systems, use the

Logamatic 4121 control unit.

Primarily, this applies to the following:

• Systems with more than three heating circuits with mixer

• Systems with a primary system

Observe the pump curve for checking the residual head. The Logamax plus GB172/GB172T can be

operated without minimum flow rate. An overflow valve is not required.

Page 43

Page 45 ff.

Page 53

Page 88 ff.

Page 43

Page 48 ff.

Page 90 ff.

Table 28 Information on the sample circuit diagram (ÆFig. 61, page 61) for all systems with Logamax plus

GB172GB172T

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6 System examples

6.2 Important hydraulic system components

6.2.1 Heating water

Heating water of poor quality encourages the formation of sludge and corrosion. This can lead to incorrect functions and can damage the heat exchanger. Therefore, heavily contaminated heating systems should be flushed through thoroughly with tap water prior to filling.

To prevent damage through scale build-up, the fill water may require treating, subject to the level of fill water hardness, system volume and the overall system output.

Total boiler

output

in kW in °dh in m

Sum of alkaline earths/total hardness

of the fill and top-up water

Max. amount of fill and top-up water V

Q < 50 Requirements according to Fig. 65 Requirements according to Fig. 65

Table 29 Table for aluminium heat exchangers

V [m

]

3,00 2,80 2,60 2,40 2,20

2,00 1,80 1,60 1,40 1,20 1,00 0,80 0,60 0,40 0,20 0,00

Fig. 65 Water treatment limits for single boiler systems

≤ 100 kW

≤ 50 kW

0 5 10 15 20 25 30

[°dH]

6 720 642 463-35.1il

≤

50 kW and ≤100 kW

max

A Above the curves, use fully desalinated fill water with a

conductivity of ≤ 10 μS/cm

B Below the curves, fill with untreated tap water that meets

the requirements of the Drinking Water Ordinance [Germany] Water hardness

V Water volume over the service life of the boiler

The current guideline VDI 2035“ Prevention of damage in hot water heating systems” (as of 12/2005) aims to simplify the application and accommodate the trend towards more compact appliances with higher heat transfer rates. The diagram in Fig. 65 enables the permissible amount of fill and top-up water to be checked that can be filled during the service life of the boiler without special treatment, subject to the hardness (°dH) and the respective boiler output. Suitable water treatment steps are required if the water volume lies above the respective limit curve in the diagram.

Suitable measures are as follows:

• Use of desalinated fill water with a conductivity of ≤ 10 μS/cm. No requirements are made of the pH value of the fill water. After filling the system, a low-salt operation results with a conductivity of generally 50 - 100 μS/cm.

• System separation by means of a heat exchanger; only fill the boiler circuit with untreated water (no chemicals, no softening).

To prevent the ingress of oxygen into the heating water, size the expansion vessel correctly (Æ page 70).

When installing pipes that are permeable to oxygen, e.g. in underfloor heating systems, provide system separation by means of a heat exchanger (Æ Fig. 67, page 68).

When modernising existing systems, protect the gas condensing boiler against sludge build-up from the existing heating system. For this purpose, the installation of a dirt trap into the common return line is strongly recommended. A dirt trap is not required if a new system is thoroughly flushed prior to filling, and loose particles as a result of oxygen corrosion can be prevented.

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6 System examples

6.2.2 Hydraulics for maximum utilisation of the condensing effect

The Logamax plus GB172/GB172T gas condensing boilers require no minimum flow rate.

6.2.3 Underfloor heating system

Underfloor heating systems are the ideal combination for Logamax plus GB172/GB172T gas condensing boilers on account of their low design temperatures. We recommend the weather-compensated operation combined with a separate room temperature-dependent control because of the heat-up inertia. The Logamatic EMS control system with RC35 programming unit is suitable for this.

A temperature limiter (TWH) is required to protect the underfloor heating system. Connect this at the terminal strip for electrical connections, i.e. the terminal for the external switching contact, using a floating contact. The contact thermostat AT 90, part no. 80 155 200, can be used as a temperature limiter, for example.

Screed drying with underfloor heating systems can also be achieved without mixer module; this requires the RC35 programming unit.

1. Underfloor heating system directly downstream

An underfloor heating system directly downstream is only feasible with pipes that are impermeable to oxygen in accordance with DIN 4726. This is to prevent damage to the heat exchanger as a result of oxygen corrosion. The maximum transferable output of the Logamax plus GB172/GB172T with underfloor heating system directly downstream is limited (Æ Table 30 and page 88).

Maximum transferable output

Logamax plus

at 10 K temperature

differential and 200 mbar

residual head

in kW

GB172 all models 10.0

Table 30 Maximum transferable output of the

Logamax plus GB172/GB172T with underfloor heating system directly downstream

2. Underfloor heating system not directly downstream

Where a higher output is to be transferred, an underfloor heating system not directly downstream is required. This circuit requires a low loss header with flow temperature sensor and a secondary pump for the heating circuit (Æ Fig. 66).

Logamax plus

GB172

RC35

HK1

BC25

RKVK

230 V AC 50 Hz

TWH

HS…(-E)

PH1

SMF

6 720 646 236-13.1il

Fig. 66 Example of an underfloor heating system not

directly downstream

AG Expansion vessel BC25 Base controller FA Outside temperature sensor

(standard delivery of the RC35 programming unit for weather-compensated control)

FK Flow temperature sensor HK Heating circuit HS Heating circuit quick installation set KR Check valve RC35 Programming unit PH Heating circuit pump (secondary pump) RK Boiler return RS Cylinder return SA Line control and shut-off valve SMF Dirt filter SU Three-way diverter valve TWH Temperature limiter - underfloor heating circuit VK Boiler flow VS Cylinder flow WH Low loss header

Safety shut-off valve recommended Additional RC25/RC20 RF programming unit feasible as remote control, if the RC35 programming unit has been clipped into the boiler

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6 System examples

3. Underfloor heating system with system separation

Provide system separation for underfloor heating systems with pipes that are permeable to oxygen. The underfloor heating circuit must be protected separately, downstream of the heat exchanger, by means of an expansion vessel, safety valve and temperature limiter (Æ Fig. 67). Size the heat exchanger in accordance with the selected system temperatures. The pressure drop on the primary side (boiler circuit) must be lower than the residual head of the pump integrated into the Logamax plusGB172/GB172T.

Logamax plus

GB172

RC35

HK1

BC25

230 V AC 50 Hz

RSVS

RKVK

TWH

SMF

ÜV

PH1

6 720 646 236-14.1il

Fig. 67 Example of an underfloor heating system with

system separation via a heat exchanger with pipes that are permeable to oxygen

AG Expansion vessel BC25 Base controller FA Outside temperature sensor (standard delivery of the

RC35 programming unit for weather-compensated control)

FK Flow temperature sensor HK Heating circuit PH Heating circuit pump (secondary pump) RC35 Programming unit RH Heating circuit return RK Boiler return RS Cylinder return SA Line control and shut-off valve SMF Dirt filter SU Three-way diverter valve TWH Temperature limiter - underfloor heating circuit ÜV Overflow valve VK Boiler flow VH Heating system flow VS Cylinder flow WT Heat exchanger for system separation

Overflow valve not required for variable speed pumps (Æ Fig. 67) Safety shut-off valve recommended Additional RC25/RC20 RF programming unit may be used as a remote. SMF recommended

6.2.4 Heating circuit pump

Heating circuit pump

If, in the case of a low temperature spread (e.g. 40/30 °C underfloor heating system), the residual head of the integral pump is insufficient to overcome the system pressure drop downstream, install a second pump externally. For this, use a low loss header to provide hydraulic separation.

An adequately sized heating circuit pump is integrated into the Logamax plus GB172/ GB172T. Fig. 68 to Fig. 70 show the available residual head for all boiler sizes. The 3-way diverter valve that is integrated in the boiler was taken into account. Constant pressure of 200 bar is the pump default setting.

H/m

200

6 720 641 280-26.2O

400

600

800

1000

1200

V/l/h

Fig. 68 Residual head of the Logamax plus

GB172-14/20/24/24 K heating circuit pump

H/m

6 720 646 236-24.2O

200 400 600

800

120010000

V/l/h

Fig. 69 Residual head of the heating circuit pump

Logamax plus GB172-24 T50

a Pump curve at maximum pump rate (100 %) b Pump curve at minimum pump rate (10 %) H Residual head

V Flow rate 1 Pump parameter: constant pressure 150 mbar 2 Pump parameter: constant pressure 200 mbar (standard

setting)

3 Pump parameter: constant pressure 250 mbar 4 Pump parameter: constant pressure 300 mbar

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H/m

6 System examples

6720619605-40.2O

200 400 600 800

1000

1200

V/l/h

Fig. 70 Residual head of the heating circuit pump

Logamax plus GB172T

Key to Fig. 70: 1 Pump parameter field constant pressure 150 mbar

2 Pump parameter field constant pressure 200 bar

(default setting)

3 Pump parameter field constant pressure 250 mbar 4 Pump parameter field constant pressure 300 mbar A Pump curve at maximum pump rate B Pump curve at minimum pump rate H Residual head

V Flow rate

Anti-seizing control

Independently of the operation of the internal pump in the Logamax plus GB172/GB172T gas condensing boilers, the BC25 base controller starts a pump test run if the heating circuit control unit has not required any heat for 24 h. This prevents the pump from seizing up.

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6 System examples

6.2.5 Expansion vessel

DIN-EN 12828 specifies that water-based heating systems must be equipped with an expansion vessel (AG) [EV].

An expansion vessel is either already integrated into the GB172/GB172T condensing boilers or is available as an accessory.

Additional EV may be

integrated as an option

(accessory; part no.

7 738 110 266)

Expansion vessel

integrated

EV may be integrated as

an option (accessory;

part no. 7 736 995 013) GB172-14/20/24 – 12 l – GB172-24 K, GB172-24 T50 12 l – – GB172-14 T120, GB172-14/20 T150,

GB172-20 T100S, GB172-14/24 T150S

18 l – 12 l

GB172-14/20 T210SR 12 l – –

Table 31 Specification of the expansion vessel

The expansion vessels have a pre-charge pressure of

0.75 bar and a response pressure of 3 bar.

Rough verification of an integral expansion vessel or selection of a separate expansion vessel

1. EV pre-charge pressure

pst=

Form. 1 EV pre-charge pressure (at least 0.5 bar)

p0EV pre-charge pressure in bar pstStatic pressure of the heating system in bar

(subject to building height)

2. Fill pressure

p00,5 bar+=

Form. 2 Fill pressure (at least 1.0 bar)

paFill pressure in bar p

EV pre-charge pressure in bar

3. System volume

Subject to various heating system parameters, the system volume can be checked in Fig. 71.

(l)

2000

1000

500 400

300

17 5

10 0

50 40

3,5

7 747 009 801-34.1il

5100

3010

5040

Fig. 71 Guidelines for average water content

of heating systems (acc. to ZVH guideline 12.02)

QKRated system output

VAAverage total system water content a Underfloor heating system b Steel radiators to DIN 4703 c Cast radiators to DIN 4703 d Panel radiators e Convector heaters

a b

QK (kW)

Example 1

Given

• n System output Q

= 18 kW

• o Panel radiators Check

• p Total system water content = 175 l (Æ Fig. 71, curve d)

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6 System examples

4. Maximum permissible system volume

Subject to the maximum flow temperature ϑ established and the EV pre-charge pressure p

to be

determined in accordance with formula 1 the maximum system volume for different EVs can be checked in table 32.

The maximum system volume identified by point 3 on the graph in Fig. 71 must be less than the maximum permissible system volume. If that is not the case, select a larger expansion vessel.

Flow

temperature

Pre-charge

pressure p

12 l 18 l 25 l 35 l 50 l 80 l

Maximum permissible system volume V

Example 2

Given

• n Flow temperature ϑ

• o EV pre-charge pressure p

• p System volume V

= 50 °C

= 175 l

= 1.00 bar

Check

• q An EV with 12 litre capacity is required as the

system volume determined in accordance with fig. 71 is less than the maximum permissible system volume.

Expansion vessel

in °C in bar in litres in litres in litres in litres in litres in litres

0.75 101 216 300 420 600 960

1.00 77 190 265 370 525 850

1.25 53 159 220 309 441 705

1.50 29 127 176 247 352 563

0.75 126 260 361 506 722 1155

1.00 96 230 319 446 638 1020

1.25 66 191 266 372 532 851

1.50 36 153 213 298 426 681

0.75 161 319 443 620 886 1417

1.00 122 282 391 547 782 1251

1.25 84 235 326 456 652 1043

1.50 46 188 261 365 522 835

0.75 216 403 560 783 1120 1792

1.00 164 355 494 691 988 1580

1.25 113 296 411 576 822 1315

1.50 62 237 329 461 658 1052

0.75 308 524 727 1018 1454 2326

o 1.00 q 234 462 642 898 1284 2054

n 50

1.25 161 385 535 749 1070 1712

1.50 88 308 428 599 856 1369

0.75 480 699 971 1360 1942 3107

1.00 366 617 857 1200 1714 2742

1.25 251 514 714 1000 1428 2284

1.50 137 411 571 800 1142 1827

Table 32 Maximum permissible system volume subject to the flow temperature and the required pre-charge pressure

of the EV

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

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6 System examples

6.3 Boiler hydraulics for appliances with integral DHW heating

6.3.1 System example for the Logamax plus GB172-24 K with integral DHW heating according to the instantaneous water heater principle with RC25/RC20 RF or RC35 programming unit for one heating circuit

RC35

BC25

Fig. 72 Circuit diagram for the system example

FA Outside temperature sensor 1 Position on the heat source 2 Position on the heat source or on the wall 3 Position on the wall

If the system is regulated via the RC35 or RC25 programming unit in weather-compensated mode

Logamax plus GB172 K

6 720 641 280-27.2O

For a download of this hydraulic system scheme (number 3-1-1-2-1) see the Buderus hydraulics database at www.buderus.de/hydraulikdatenbank

This circuit diagram is only a schematic illustration and provides a non-binding indication of a possible hydraulic circuit. Install safety equipment in accordance with applicable standards and local regulations.

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 73

Brief description

• Logamax plus GB172-24 K gas condensing boiler with modulating operation and integral DHW heating

• Room temperature-dependent control as standard application in conjunction with the RC25/RC20 RF or RC35 programming unit. The FA outside temperature sensor for the RC35 and RC25 programming units also enables weather-compensated control.

Operational description

The modulating operation of the Logamax plus GB172-24 K is regulated by the Logamatic BC25 base controller. The BC25 also regulates the direct DHW heating via a plate heat exchanger. DHW mode timings can be regulated in conjunction with the RC35 programming unit.

Special design information

• This system layout is also suitable for underfloor heating systems (Æ chapter 6.2.3, page 67).

• For the DHW connection on Logamax plus GB172-24 K combi boilers, use only pipework that is compatible with copper. Make all connections on the cold water and DHW sides in accordance with DIN 1988 and DIN 4753.

• A 12 l expansion vessel is already factory-fitted into the Logamax plus GB172-24 K. Check its size is adequate.

• Where required, adjust the setting of the differential pressure-dependent pump inside the Logamax plus GB172 subject to the relevant system (Æ chapter 6.2.4, page 68).

• The default setting for pump modulation Δp = constant is 200 mbar.

6 System examples

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6 System examples

6.3.2 System example for the Logamax plus GB172-24 T50 with integral DHW heating with RC25/RC20 RF or RC35 programming unit for one heating circuit

RC35

BC25

Logamax plus GB172 T50

Fig. 73 Circuit diagram for the system example

FA Outside temperature sensor 1 Position on the heat source 2 Position on the heat source or on the wall

If the system is regulated via the RC35 or RC25 programming unit in weather-compensated mode

You can download this system hydraulic scheme (number 3-1-1-2-16) from the Buderus hydraulics database at www.buderus.de/hydraulikdatenbank

6 720 646 236-04.1il

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 75

Brief description

• Logamax plus GB172-24 T50 gas condensing boiler with modulating operation and integral DHW heating by means of an integrated 48 l DHW cylinder

Operational description

The modulating operation of the Logamax plus GB172-24 T50 is regulated by the Logamatic BC25 base controller. The BC25 also regulates DHW heating via the internal indirect coil. DHW mode and DHW circulation mode (option) can have timings set in conjunction with the RC35 programming unit.

Special design information

• This system layout is also suitable for underfloor heating systems (Æ chapter 6.2.3, page 67).

• The DHW pipework of the GB172-24 T50 is made from stainless steel without use of copper. Consequently, this appliance is also suitable for zinc-plated/galvanised pipework. Make all connections on the cold water and DHW sides in accordance with DIN 1988 and DIN 4753.

• A 12 l expansion vessel is already factory-fitted into the Logamax plus GB172-24 T50. Check its size is adequate.

• An expansion vessel that can be integrated (DHW) (2 l; 3.5 bar) is available as an accessory.

• Where required, adjust the setting of the differential pressure-dependent pump inside the Logamax plus GB172-24 T50 subject to the relevant system (Æ chapter 6.2.4, page 68).

• The default setting for pump modulation Δp = constant is 200 mbar.

• Requires accessory “DHW circulation line connection”. Linking the cold water distributor inside the GB172-24 T50 with the on-site DHW circulation line.

6 System examples

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6 System examples

6.3.3 System example for the Logamax plus GB172-20 T100S or GB172-14/24 T150S with integral DHW heating by means of a stratification cylinder with RC25/RC20 or RC35 programming unit for one heating circuit

RC35

BC25

Fig. 74 Circuit diagram for the system example

FA Outside temperature sensor PZ DHW circulation pump 1 Position on the heat source 2 Position on the heat source or on the wall

If the system is regulated via the RC35 or RC25 programming unit in weather-compensated mode

Logamax plus

GB172 T... S

6720648096-13.1O

You can download this system hydraulic scheme (number 2-2-2-13) from the Buderus hydraulics database at www.buderus.de/hydraulikdatenbank

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 77

Brief description

• Logamax plus GB172-20 T100S or GB172-14/24 T150S gas condensing boiler with modulating operation and integral DHW heating by means of an integrated stratification cylinder with a capacity of 101 l or 148 l.

Operational description

The modulating operation of the Logamax plus GB172-20 T100S and GB172-14/24 T150S is regulated by the Logamatic BC25 base controller. The BC25 also regulates DHW heating via the internal stratification cylinder. DHW mode and DHW circulation mode (option) can have timings set in conjunction with the RC35 programming unit.

6 System examples

Special design information

• From an overall hardness level of 21 °dH upwards, a dislodging of scale inside the plate heat exchanger must be expected. For this case we recommend the use of either the GB172-14 T120 or the GB172-14/20 T150 with cylinder with internal indirect coil or alternatively the use of a water treatment facility.

• This system layout is also suitable for underfloor heating systems (Æ chapter 6.2.3, page 67).

• Make all connections on the cold water and DHW side in accordance with DIN 1988 and DIN 4753.

• An 18 l expansion vessel is already factory-fitted into the Logamax plus GB172-20 T100S and GB172-14/24 T150S. Check its size is adequate.

• An expansion vessel that can be integrated (DHW) (8 l; 3.5 bar) is available as an accessory.

• Adjust the setting of the differential pressure regulated pump in the Logamax plus GB172-20 T100S and GB172-14/24 T150S in accordance with the specific system, if required (Æ chapter 6.2.4, page 68).

• The default setting for pump modulation Δp = constant is 200 mbar.

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6 System examples

6.3.4 System example for the Logamax plus GB172-14 T120 and GB172-14/20 T150 with integral DHW heating via internal indirect coil with RC25/RC20 RF or RC35 programming unit for one heating circuit

RC35

BC25

Fig. 75 Circuit diagram for the system example

FA Outside temperature sensor PZ DHW circulation pump 1 Position on the heat source 2 Position on the heat source or on the wall

If the system is regulated via the RC35 or RC25 programming unit in weather-compensated mode

Logamax plus

GB172 T

6720648096-11.1O

You can download this system hydraulic scheme (number 2-2-2-12) from the Buderus hydraulics database at www.buderus.de/hydraulikdatenbank

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 79

Brief description

• Logamax plus GB172-14 T120 or GB172-14/20 T150 gas condensing boiler with modulating operation and integral DHW heating by means of a cylinder with internal indirect coil with a capacity of 115 l or 143 l.

Operational description

The modulating operation of the Logamax plus GB172-14 T120 and GB172-14/20 T150 is regulated by the Logamatic BC25 base controller. The BC25 also regulates DHW heating via the internal indirect coil. DHW mode and DHW circulation mode (option) can have timings set in conjunction with the RC35 programming unit.

Special design information

• This system layout is also suitable for underfloor heating systems (Æ chapter 6.2.3, page 67).

• The DHW pipework of the GB172-14 T120 and GB172-14/20 T150 is made from stainless steel without use of copper. Consequently, this appliance is also suitable for zinc-plated/galvanised pipework. Make all connections on the cold water and DHW sides in accordance with DIN 1988 and DIN 4753.

• An 18 l expansion vessel is already factory-fitted into the Logamax plus GB172-14 T120 and GB172-14/20 T150. Check its size is adequate.

• An expansion vessel that can be integrated (DHW) (8 l; 3.5 bar) is available as an accessory.

• Adjust the setting of the differential pressure regulated pump in the Logamax plus GB172-14 T120 and GB172-14/20 T150 in accordance with the specific system, if required (Æ chapter 6.2.4, page 68).

• The default setting for pump modulation Δp = constant is 200 mbar.

6 System examples

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6 System examples

6.3.5 System example for the Logamax plus GB172-14/20 T210SR with a heating circuit without mixer directly downstream plus solar DHW heating

FSK

PSS

KS01

SM10

BC25

RC35

Logamax plus

GB172 T210SR

Fig. 76 Circuit diagram for the system example

FA Outside temperature sensor (standard delivery of the

RC35 programming unit for weather-compensated control)

FSK Collector temperature sensor S01 Logasol solar pump station PSS Solar circuit pump PZ DHW circulation pump 1 Position on the heat source 2 Position on the heat source or on the wall

1) The components of the KS01 complete station are

already integrated into the GB172-14/20 T210SR compact heating centre.

6720648096-12.1O

For a download of this hydraulic system scheme (number 2-2-3-6) see the Buderus hydraulics database at www.buderus.de/hydraulikdatenbank

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 81

Brief description

• The dual mode solar stratification cylinder is primarily supplied with heat by the solar thermal system. Where there is insufficient solar heat, the cylinder will be reheated by the condensing boiler via the plate-type heat exchanger mounted at the top.

• Only preheated water from the dual mode solar stratification cylinder is drawn and reheated. This safeguards the primary use of solar energy at all times. DHW heating by gas is restricted to the reheat function.

• Minimal installation effort through completely pre-assembled heating and solar unit that only needs to be connected up on site.

Special design information

• Use in detached houses on account of the dual mode solar stratification cylinder with 204 l capacity that enables the combination with two or three collectors.

• The compact heating centre already features an integral SM10 solar module.

• Solar pump station integrated into the compact heating centre, comprising solar circuit pump, expansion vessel, air vent valve, drain & fill valve, safety assembly and flow limiter.

• Solar pump station can be converted for l.h./r.h. use for optimum accessibility.

• Ideal installation of the solar connections through direct connection with locking ring fittings.

• The DHW mixer set accessory includes the DHW mixer as well as the components for DHW circulation (DHW circulation pump on site). Set the DHW mixer to 60 °C.

6 System examples

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6 System examples

6.4 Boiler hydraulics for appliances with separate DHW heating

6.4.1 System example for the Logamax plus GB172 with RC25/RC20 RF or RC35 programming unit for one heating circuit

RC35

BC25

Logalux S ...

Fig. 77 Circuit diagram for the system example

A Heating circuit for radiators without mixer B Underfloor heating system directly downstream

(transferable output (Æ Table 30, page 67): with this hydraulic circuit, system pressure drop and residual head of the integral pump must be taken into account.

FA Outside temperature sensor (standard delivery of the

RC35 programming unit for weather-compensated control, available as an accessory for RC25)

FW DHW temperature sensor PZ DHW circulation pump TW Temperature limiter 1 Position on the heat source 2 Position on the heat source or on the wall 3 Position on the wall

Logamax plus

GB172

6 720 641 280-28.2O

For a download of this hydraulic system scheme (number 3-1-1-2-2) see the Buderus hydraulics database at www.buderus.de/hydraulikdatenbank

If the system is regulated by the RC35 or RC25 in weather-compensated mode

Connection of the temperature limiter in the Logamax plus GB172

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 83

Brief description

• Logamax plus GB172 gas condensing boiler with modulating operation and separate DHW heating.

• The modulating operation of the Logamax plus is regulated by the BC25 base controller. This also regulates the DHW priority for the separate DHW cylinder via the integral 3-way diverter valve. A time profile can be selected in connection with the RC35 programming unit for heating operation in constant standby mode for DHW heating (24 hour mode). Alternatively, DHW heating can be linked to the times selected for heating operation. It is then only possible during the periods selected for heating or standby mode.

Special design information

• If no separate DHW cylinder is connected, seal the connections at the cylinder flow and return using the DHW caps ½ " (accessories).

• Generally, DHW heating takes priority (via the 3-way diverter valve either cylinder heating or heating mode).

• Order an expansion vessel of adequate size as an accessory.

• Where required, adjust the setting of the differential pressure-dependent pump inside the Logamax plus GB172 subject to the relevant system (Æ chapter 6.2.4, page 68).

• The default setting for pump modulation Δp = constant is 200 mbar.

6 System examples

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6 System examples

6.4.2 System example for Logamax plus GB172 with RC35 programming unit for one heating circuit without mixer and one with mixer with the same time channel

BC25 MM10

RC35

213

Logalux S ...

Fig. 78 Circuit diagram for the system example

FA Outside temperature sensor (standard delivery of the

RC35 programming unit for weather-compensated control)

FV Flow temperature sensor FW DHW temperature sensor PZ DHW circulation pump PH Heating circuit pump TW Temperature limiter SH Heating circuit actuator 1 Position on the heat source 2 Position on the heat source or on the wall 3 Position on the wall

1/3 2/3

Logamax plus

GB172

For a download of this hydraulic system scheme (number 3-1-1-2-3) see the Buderus hydraulics database at www.buderus.de/hydraulikdatenbank

6 720 641 280-29.2O

1) Preset at the factory

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

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Brief description

• Logamax plus GB172 gas condensing boiler with modulating operation and separate DHW heating.

• The output of the underfloor heating circuit is limited to 50 % of the appliance output.

• The distribution valve is factory-set to 1/3 of the water volume of the underfloor heating system and to 2/3 of the water volume for radiator heating systems. Generally (maximum 50 % underfloor heating; underfloor heating 40/30 °C; radiators 70/50 °C), these systems will not require further balancing.

• DHW heating with this kind of hydraulic scheme can only be heated via a 3-way diverter valve.

Special design information

• Only the RC35 programming unit and the MM10 mixer module will be required.

• Enable the heating circuit with mixer for underfloor heating systems (HK2).

• Also enable the radiator heating circuit without mixer (HK1).

• Ensure that the same time slot is set for the heating circuit without mixer as for the heating circuit with mixer.

• The ready to plug-in AT90 is used as a temperature limiter (part no. 80 155 200) for the underfloor heating.

• It is not possible to use only the heating circuit with mixer. The time window for the circuit without mixer must be the same or larger than that of the circuit with mixer.

• Order an expansion vessel of adequate size as an accessory.

6 System examples

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6 System examples

6.4.3 System example for the Logamax plus GB172 with low loss header, two heating circuits with mixer and DHW heating via cylinder primary pump

BC25 RC25MM10MM10

RC35

21333

Logalux S ...

Fig. 79 Circuit diagram for the system example

FA Outside temperature sensor (standard delivery of the

RC35 programming unit for weather-compensated control)

FK Low loss header sensor FV Flow temperature sensor FW DHW temperature sensor PZ DHW circulation pump PH Heating circuit pump TW Temperature limiter SH Heating circuit actuator 1 Position on the heat source 2 Position on the heat source or on the wall 3 Position on the wall

Logamax plus

GB172

6 720 641 280-48.2O

You can check these system hydraulics in the Buderus hydraulic database at www.buderus.de/hydraulikdatenbank

Brief description

• Logamax plus GB172 gas condensing boiler with modulating operation and separate DHW heating via cylinder primary pump

• Control of the low loss header (separation) via Logamatic BC25

• Control of both heating circuits with mixer (HK1 and HK2) via MM10 mixer module

• Both heating circuits can be controlled in weather-compensated mode, room temperature-dependent mode or weather-compensated mode with room temperature hook-up mode.

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

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Special design information

• The control of all heating circuits by means of the MM10 mixer modules enables the low loss header to be connected directly to the Logamatic BC25, making the WM10 low loss header module unnecessary.

• Optional DHW heating via an individual time channel including control of a DHW circulation pump and thermal disinfection.

• Generally, DHW heating takes priority (via the 3-way diverter valve either cylinder heating or heating mode) because of the selection of the DHW output at the RC35 programming unit.

• Size the flow and return lines to the low loss header for maximum boiler output.

• Determine the size of the low loss header in accordance with the maximum permissible flow rates:

– Installing a Tacosetter upstream of the low loss

header is recommended.

– In combination with a low loss header, the integral

pump in the GB172 must be controlled subject to output (setting 0 at the RC35 programming unit).

6 System examples

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

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6 System examples

6.4.4 System example for the Logamax plus GB172 with low loss header, one heating circuit without mixer, one heating circuit with mixer and separate DHW heating via a 3-way diverter valve

BC25

RC35

MM10WM10

RC25

Logalux S ...

Fig. 80 Circuit diagram for the system example

FA Outside temperature sensor (standard delivery of the

RC35 programming unit for weather-compensated control)

Logamax plus

GB172

6 720 641 280-30.2O

You can check these system hydraulics in the Buderus hydraulic database at www.buderus.de/hydraulikdatenbank

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 89

Brief description

• Control of the low loss header (separation) and one heating circuit without mixer (HK1) via WM10 low loss header module.

• Control of one underfloor heating circuit with mixer (HK2) via MM10 mixer module.

• Both heating circuits can be controlled in weathercompensated mode, room temperature-dependent mode or weather-compensated mode with room temperature hook-up.

Special design information

• Optional DHW heating via an individual time channel including control of a DHW circulation pump and thermal disinfection.

• Generally, DHW heating takes priority (via the 3-way diverter valve either cylinder heating or heating mode) because of the selection of the DHW output at the RC35 programming unit.

• Size the flow and return lines to the low loss header for maximum boiler output.

• Determine the size of the low loss header in accordance with the maximum permissible flow rates.

• Installing a Tacosetter upstream of the low loss header is recommended.

• In combination with a low loss header, the integral pump in the GB172 must be controlled subject to output (setting 0 at the RC35 programming unit).

• Order an expansion vessel of adequate size as an accessory.

6 System examples

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6 System examples

6.4.5 System example for the Logamax plus GB172 with a heating circuit without mixer directly downstream, solar DHW heating and DHW reheating via a 3-way diverter valve

FSK

PSS

KS01

SM10

BC25

RC35

FSS

Logalux SL...

Fig. 81 Circuit diagram for the system example

FA Outside temperature sensor (standard delivery of the

RC35 programming unit for weather-compensated control)

FSK Collector temperature sensor FSS Cylinder temperature sensor FW DHW temperature sensor KS01 Logasol solar pump station PSS Solar circuit pump 1 Position on the heat source 2 Position on the heat source or on the wall 3 Position on the wall

Logamax plus

GB172

6 720 641 280-31.2O

For a download of this hydraulic system scheme (number 3-1-1-3-1) see the Buderus hydraulics database at www.buderus.de/hydraulikdatenbank

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 91

Brief description

• Differential pressure-dependent operation of the heating circuit pump in the Logamax plus GB172

• Control of solar DHW heating with dual mode DHW cylinder via SM10 solar module; for this, the thermal disinfection function of the RC35 programming unit is automatically disabled.

• DHW reheating via the integral 3-way diverter valve of the Logamax plus.

Special design information

• The solar pump station can be delivered from the factory with an integral SM10 solar module. This is the recommended version for the Logamax plus GB172 as no modules can be integrated into this boiler.

• The intelligent linking of boiler and solar controllers with the SM10 solar module provides an optimised solar yield and saves reheating energy.

• Optional DHW via an individual time channel including control of a DHW circulation pump.

• Generally, DHW heating takes priority (via the 3-way diverter valve either cylinder heating or heating mode) because of the selection of the DHW output at the RC35 programming unit.

• Order an expansion vessel of adequate size as an accessory.

• Where required, adjust the setting of the differential pressure-dependent pump inside the Logamax plus GB172 subject to the relevant system (Æ chapter 6.2.4, page 68).

• The default setting for pump modulation Δp = constant is 200 mbar.

6 System examples

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6 System examples

6.4.6 System example for the Logamax plus GB172 with solar central heating backup and one heating circuit with mixer

MM10

RC35

FSK

SC40

BC25

KS01

PSS

FSS

Logalux P750 S

Fig. 82 Circuit diagram for the system example

FA Outside temperature sensor (standard delivery of the

RC35 programming unit for weather-compensated control)

FK Flow temperature sensor FP Buffer cylinder temperature sensor FR Return temperature sensor FSK Collector temperature sensor FSS Cylinder temperature sensor FV Flow temperature sensor FW DHW temperature sensor KS01 Logasol solar pump station PSS Solar circuit pump PZ DHW circulation pump PH Heating circuit pump TW Temperature limiter SH Heating circuit actuator SU Three-way diverter valve SWE Actuator, heat supply 1 Position on the heat source 2 Position on the heat source or on the wall 3 Position on the wall

SWE

Logamax plus

GB172

Remove the plug of the internal 3-way diverter valve

6 720 641 280-32.3O

and adjust parameter 2.1F in the BC25

For a download of this hydraulic system scheme (number 3-1-1-4-1) see the Buderus hydraulics database at www.buderus.de/hydraulikdatenbank

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 93

Brief description

• Solar central heating backup and DHW heating by means of a combi buffer cylinder

• DHW reheating by the GB172 via an external 230 V 3-way valve (accessory, part no. 7 736 995 008)

• Control of the solar DHW heating and central heating backup with return changeover via Logamatic SC40 solar controller.

• External heat recognition via low loss header temperature sensor (accessory); if sufficient external heat is available from the buffer cylinder, the internal pump as well as the appliance burner will be switched off.

• The heating circuits are regulated via a 3-way mixer.

Special design information

• In combination with a low loss header, the integral pump in the GB172 must be controlled subject to output (setting 0 at the RC35 programming unit).

• If the buffer cylinder temperature is higher than the heating return temperature, the buffer cylinder will also be used for central heating via the Logamatic SC40 solar controller and the HZG-Set.

• The RC35 programming unit enables an individual time channel for DHW heating.

• Installing a Tacosetter upstream of the low loss header is recommended.

• The low loss header “across” is unsuitable for this hydraulic layout. Use the low loss headers WHY 80/60 or WHY 120/80.

• Order an expansion vessel of adequate size as an accessory.

6 System examples

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7 Condensate drain

Route the condensate from gas condensing boilers into the public sewer system in accordance with local regulations. It is crucial to determine whether the condensate must be neutralised prior to induction into the sewer system. This depends on the boiler output and the respective regulations of the local water authority (Æ Table 33). Code of Practice A 251 of the ATV applies [in Germany] to the calculation of the annual amount of condensate. This Code of Practice lists a specific amount of condensate as empirical value of maximum

0.14 kg/kWh.

It is appropriate to check local regulations regarding draining condensate in good time prior to installation. The local water supply utility is the responsible body for questions concerning waste water.

Neutralisation obligation

Boiler output Neutralisation

in kW

≤ 25 no

> 25 to ≤ 200 no

> 200 yes

Table 33 Neutralisation obligation for gas condensing

boilers

1) Neutralising the condensate is required when draining the domestic waste water into a small treatment plant and for buildings and properties where the waste pipes do not meet the material requirements of the ATV Code of Practice A 251 [Germany].

2) Neutralisation of the condensate is required for buildings where the requirement of adequate admixing (Æ Table 34) with domestic waste water (at a ratio of 1:25) is not met.

For small systems with less than 25 kW output, there is no obligation to neutralise (Æ Table 33) if the waste water does not flow into small treatment plants or if the drain lines meet the material requirements of the ATV Code of Practice A 251 [Germany].

Materials for condensate hoses

According to the ATV datasheet A 251, the following are suitable materials for condensate hoses:

• Clay pipes (to DIN-EN 295-1)

• Rigid PVC pipes

• PVC pipes (polyethylene)

• PE-HD pipes (polypropylene)

• PP pipes

• ABS-ASA pipes

• Stainless steel pipes

• Borosilicate glass pipes

If an admixing of the condensate with domestic waste water at a ratio of at least 1:25 is assured (Æ Table 34), then the following may be used:

• Fibre cement pipes

• Cast or steel pipes to DIN 19522-1 and DIN 19530-1 and 19530-2

Copper pipes are unsuitable for draining condensate.

Adequate admixing

If the conditions in table 34 are met, then adequate admixing of condensate with domestic waste water will result. The above details refer to 2000 hours of full utilisation in accordance with guideline VDI 2067 (maximum value).

Boiler load

Boiler output

in kW

Amount of

condensate

in m3/a Number of employees Number of residential units

Office and commercial

buildings

25 7 ≥ 10 ≥ 1

50 14 ≥ 20 ≥ 2

100 28 ≥ 40 ≥ 4

150 42 ≥ 60 ≥ 6

200 56 ≥ 80 ≥ 8

Table 34 Conditions for an adequate admixing of condensate with domestic waste water

1) Maximum values at a system temperature 40/30 °C and 2000 hours run

2) Combustion output

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Residential buildings

Page 95

7 Condensate drain

7.1 Condensate drain from the gas condensing boiler and the flue

To ensure the condensate generated in the flue can drain via the gas condensing boiler, route the flue inside the installation room with a slight slope (≥ 3°, i.e. approx. 5 cm height differential per metre) towards the gas condensing boiler.

Observe the relevant regulations concerning waste drainage from buildings and other appropriate local regulations. Ensure particularly that the drain line is ventilated in accordance with regulations and that it drains freely (Æ Fig. 83) into a drain outlet with a siphon, to prevent the stench trap being emptied and to prevent condensate from backing up into the appliance.

7.2 Condensate drain from a moisture-resistant chimney

Drain condensate in accordance with the details specified by the chimney manufacturer if a moisture-resistant chimney (suitable for condensing boilers) is used.

Via stench trap with funnel, the condensate from the chimney can be routed indirectly into the building drain together with the condensate from the gas condensing boiler.

3°

6 720 641 280-33.1il

Fig. 83 Condensate drain from the gas condensing

boiler and a flue via the neutralising system

1 Neutralising system

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

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8 Installation

8.1 Selection aid for connection accessories Logamax plus GB172

Connection accessories

Accessories for heating circuit and gas connection

U-MA – Mounting plate 7 095 450 z z z z z z z z z z z z z z z z MR – Mounting frame AS5-AP – connection set 5 AS5-UP – connection set 5 DHW caps ½ " 7 709 000 227 z z – – – – – – – – – – – – – – MKU – panel for unfinished walls

Accessories for appliances with integral DHW heating

AS6-AP – connection set 6 AS6-UP – connection set 6 DHW line connection 7 716 780 233 – – – –  –––––––––– Expansion vessel (DHW) 2 l; 3.5 bar

Accessories for external DWH cylinders

AS E – cylinder connection set AS7-AP – connection set 7 AS7-UP – connection set 7 AS8-AP – connection set 8 AS8-UP – connection set 8 N-Flex GB172-/U152/U154 GB172 cover 7 719 002 7552)    – –   – –   – – – – GB172 cover with H65 W

Part no.

without cylinder

GB172-24 K

with integral DHW heating

AP UP AP UP AP UP AP UP AP UP AP UP AP UP AP UP

7 736 995 014  ––––––

7 736 613 430 z – – – – – – – – – – – – – z –

7 736 613 431 – z –––––––––––––z

87 094 080 –  –  –  –  –  –  –  – 

7 736 613 432 – – z – z –––––––––––

7 736 613 433 – – – z – z – – – – – – – – – –

7 716 780 229 – – – –   – – – – – – – – – –

5 991 387 – – – – – – – – – – – – z z z z

7 736 613 434 – – – – – – z –––z – z –––

7 736 613 435 – – – – – – – z – – – z – z – –

7 736 613 436 – – – – – – – – z –––––––

7 736 613 437 – – – – – – – – – z – – – – – –

7 095 484 – – – – – – – – – – – – – – zz

7 719 003 026 – – – – – – – –  ––––––

GB172 T50

with integral DHW heating

with H65 W

hanging below

with H65 W

hanging adjacent

floor standing below

with WU120 W/WU160 W

with S120 W

floor standing below

floor standing adjacent

with SU160 W/SU200 W/SU300 W

Table 35 Selection aid for connection accessories (ÆTable 36, page 98 ff.)

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8 Installation

Connection accessories

Accessories for the sanitary side of DHW cylinders

S-Flex – connection set 87 094 838 – – – – – –  –– U-DM – Pressure reducer for installation in S-Flex ZP – DHW circulation pump connection

Accessories for flue connection

Pre-installation bracket, flue gas Replacement connection piece Ø 60/100 DHW circulation pipe for WU120 W/WU16 W

Part no.

without cylinder

GB172-24 K

with integral DHW heating

AP UP AP UP AP UP AP UP AP UP AP UP AP UP AP UP

7 095 604 – – – – – –         – –

87 094 842 – – – – – –  –– ––

7 736 995 015  ––––––

7 719 003 381                

7 719 001 934 – – – – – – – – – –  ––––

GB172 T50

with integral DHW heating

with H65 W

hanging below

with H65 W

hanging adjacent

with WU120 W/WU160 W

floor standing below

with S120 W

floor standing below

floor standing adjacent

with SU160 W/SU200 W/SU300 W

Table 35 Selection aid for connection accessories (ÆTable 36, page 98 ff.)

1) The U-MA connecting plate will not be required when utilising the mounting frame.

2) Cannot be combined with S-Flex

3) If no pressure reducer is installed in the building.

AP Installation on finished walls UP Installation on unfinished walls

z Required  Option

– Cannot be used

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

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8 Installation

Connection accessories for Logamax plus GB172-14/20/24/24 K Designation Description Accessories for heating circuit and gas connection

U-MA Mounting plate

Mounting frame

AS5-AP – connection set 5

AS5-UP – connection set 5

• Heating circuit R ¾

• Cold water and DHW R ½

• Gas R ½

• Suitable for GB172 (not for GB172-24 T50)

• No U-MA mounting plate required

• Installation on finished walls

• Comprising: – HA (2 service valves, heating circuit Rp ¾ ) – GA-BS (straight-through gas tap Rp ½ with

integral fire safety valve)

–Drain outlet kit

• Installation on unfinished walls

• Comprising: – HU (2 service valves, heating circuit R ¾ ) – GU-BS (right-angle gas tap R ½ with

integral fire safety valve)

–Drain outlet kit

DHW caps ½ "

• Required during installation if no DHW cylinder is connected

• For single appliances, combi boilers,

MKU panel for unfinished walls

appliances with H65 W hanging adjacent, with WU120 W/WU160 W/S120 floor standing and with SU160/200/300 W

• Pre-installation on unfinished walls

Accessories for combi boilers

• Installation on finished walls

• Comprising: – HA (2 service valves, heating circuit Rp ¾ )

AS6-AP connection set 6

– GA-BS (straight-through gas valve

Rp ½ with integral fire safety valve) –Drain outlet kit – U-BA (DHW connection set with

connection valve Rp ½ and spacer)

Table 36 Connection accessories for Logamax plus GB172-14/20/24/24 K

(assignment

Table 35; installed dimensionsÆFig. 30 to Fig. 34, page 37 ff.)

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Page 99

Connection accessories for Logamax plus GB172-14/20/24/24 K

Designation Description

• Installation on unfinished walls

• Comprising:

– HU (2 service valves, heating circuit R ¾ )

– GU-BS (right-angle gas tap R ½ with

AS6-UP – connection set 6

integral fire safety valve) –Drain outlet kit – U-BU (DHW connection set complete with

right-angle valve R ½ , connection bend,

two copper pipes, two union nuts and two

pipe collars)

Accessories for external DWH cylinders

• DHW temperature sensor Ø 6 mm for DHW heating with plug for connection to the boiler terminal strip

AS E cylinder connection set

• Including ¼ circular sensor segments (dummy segments) and spring hook (plastic spiral) for temperature sensor Ø 6 mm in conjunction with DHW cylinders larger than 120 l

• Plug for cylinder primary pump and DHW circulation pump

• Installation on finished walls

• For DHW cylinder wall mounted below or freestanding below

AS7-AP connection set 7

• Comprising: –HA (description Æ AS5-AP) – GA-BS (description Æ AS5-AP) –Drain outlet kit – U-Flex (flexible pipe set on the heating

circuit side with connection bend)

• Installation on unfinished walls

• For DHW cylinder wall mounted below or freestanding below

AS7-UP – connection set 7

• Comprising: –HU (description Æ AS5-UP) – GU-BS (description Æ AS5-UP) –Drain outlet kit – U-Flex (flexible pipe set on the heating

circuit side with connection bend)

8 Installation

• Installation on finished walls

• For wall mounted adjacent DHW cylinders

• Comprising:

AS8-AP connection set 8

–HA (description Æ AS5-AP) – GA-BS (description Æ AS5-AP) –Drain outlet kit – N-Flex (flexible pipework set for the heating

circuit side)

Table 36 Connection accessories for Logamax plus GB172-14/20/24/24 K

(assignment

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172

Table 35; installed dimensionsÆFig. 30 to Fig. 34, page 37 ff.)

Page 100

8 Installation

Connection accessories for Logamax plus GB172-14/20/24/24 K

Designation Description

• Installation on unfinished walls

• For wall mounted adjacent DHW cylinders

• Comprising:

AS8-UP – connection set 8

–HU (description Æ AS5-UP) – GU-BS (description Æ AS5-UP) –Drain outlet kit – N-Flex (flexible pipework set for the heating

circuit side)

N-Flex Flexible pipe set on the heating circuit side

Cover for GB172

Cover for GB172 with Logalux H65 W

Accessories for the sanitary side of DHW cylinders

S-Flex Flexible connection set for the sanitary side

• Installation on finished walls

• For DHW cylinders SU160 W, SU200 W and SU300 W

• May be used with the GB172 and GB172-24 K without cylinder, GB172 with H65W hanging below and GB172 with WU... floor standing below

• Cannot be combined with S-Flex

• Height: 205 mm

• May be used for the GB172 with H65W hanging adjacent

• Installation on finished and unfinished walls

• For DHW cylinders wall mounted below or freestanding below H65 W, WU120 W, WU160 W and S120 W

• For H65 W wall mounted adjacent DHW cylinder with safety valve

• Non-return valve

• Cylinder pipe connection for cold water and DHW

• Cannot be combined with cover GB172

U-DM Pressure reducer

ZP DHW circulation pump connection

• Retrofit with S-Flex

• Pressure reducer to 4 bar

• For the connection of a DHW circulation pump

• For retrofitting with S-Flex

Table 36 Connection accessories for Logamax plus GB172-14/20/24/24 K

(assignment

100

Table 35; installed dimensionsÆFig. 30 to Fig. 34, page 37 ff.)

6 720 800 989 2011/06 – Technical Guide Logamax plus GB172