andrews CSC 39, CSC 59, CSC 78, CSC 93, CSCL 39 User guide

NATURAL GAS,
PROPANE & BUTANE
FIRED STORAGE
WATER HEATERS

MODELS

CSC 39
CSC 59
CSC 78
CSC 93
CSCL 39
CSCL 59
CSCL 78
CSCL 93
Auto Ignition

INSTALLATION
GUIDE,
OPERATION
AND SERVICE
MANUAL

THIS MANUAL MUST BE KEPT WITH THE APPLIANCE

October 2005

Part No. E191

© Copyright Andrews Water Heaters 2005

Reproduction of any information in this publication by any method is not permitted

unless prior written approval has been obtained from Andrews Water Heaters.

Andrews Storage Water Heaters have been designed and manufactured to comply

with current International standards of safety. In the interests of the health and

safety of personnel and the continued safe, reliable operation of the equipment,

safe working practices must be employed at all times. The attention of U.K. users is

drawn to their responsibilities under the Health and Safety Regulations 1993.

All installation and service on the Andrews Water Heater must be carried out by

properly qualified personnel, and therefore no liability can be accepted for any

damage or malfunction caused as a result of intervention by unauthorised

personnel.

The Andrews Water Heaters policy is one of continuous product improvement, and

therefore the information in this manual, whilst completely up to date at the time of

publication, may be subject to revision without prior notice.

Further information and assistance can be obtained from:

Andrews Water Heaters

Wednesbury One, Black Country New Road

Wednesbury, West Midlands WS10 7NZ

Te l: [phone] Fax: [phone]

Email: [e-mail]

Website: www.andrewswaterheaters.co.uk

THE ANDREWS WATER HEATERS COVERED IN THIS MANUAL

ARE FOR USE WITH NATURAL GAS OR LPG (PROPANE OR BUTANE) GAS ONLY

CONTENTS

SECTION 1 GENERAL AND SAFETY INFORMATION

General Information 2
British Standards and Codes of Practice 2
Health and Safety Regulations 1993 3
Effectiveness in Combating Legionellae 3

SECTION 2 TECHNICAL DATA 4

SECTION 3 INSTALLATION

Introduction 6
Location 6
Gas Supply - Natural Gas 7
Gas Supply - LPG (Propane or Butane) Gas 8
Electrical Supply 10
Flue Systems 12
Air Supply and Ventilation 18
Water Quality and Treatment 20
Water Connections 21

SECTION 4 COMMISSIONING

Filling the Heater with Water 25
Draining Water from the Heater 25
Lighting the Burner 25
Shutting Off the Burner 26
Checking Main Burner Pressure 26
Checking Pilot and Burner Flames 26
User's Safety Guide 27

SECTION 5 OPERATION

Operating Sequence 28
ECO (Energy Cut-Off) 28
Temperature Stratification (Stacking) 28

SECTION 6 SERVICING

Introduction 29
Pre-Service Operations 29
Annually 29
Six Monthly 29
Burner Assembly 30
Gas Control Valve 30
Magnesium Anodes 30
Combined Temperature and Pressure Relief Valve 31
Cleaning the Storage Vessel 31
Restart 31

SECTION 7 FAULT FINDING 32

SECTION 8 PARTS LISTS AND ILLUSTRATIONS 34

PAGE

GENERAL AND SAFETY INFORMATIONSECTION 1

The Andrews Water Heater has been designed for use with NATURAL GAS OR LPG
(PROPANE OR BUTANE) GAS only and is manufactured to give an efficient, reliable and
long service life.

To ensure the continued, trouble-free operation of your heater at maximum efficiency, it
is essential that correct installation, commissioning, operation and service procedures are
carried out strictly in accordance with the instructions given in this manual. By law,
installation and commissioning of the heater must be carried out by properly qualified
personnel.

The heater(s) must be installed in accordance with the following requirements;
The current GAS SAFETY (INSTALLATION AND USE) REGULATIONS
The current BUILDING REGULATIONS
The WATER SUPPLY (WATER FITTINGS) REGULATIONS 1999

Additionally, installation should be performed in accordance with all relevant
requirements of the Gas Supplier, Local Authority and recommendations of the British
Standards and Codes of Practice detailed below.

BS 6700: 1997 Specification for design, installation, testing and maintenance of

services supplying water for domestic use within buildings and their
curtilages. This standard supersedes the following British Standards
and Codes of Practice: CP99, CP310, CP324, 202, CP342 Part 2,
Centralised Hot Water Supply.

BS 5440:2000 Installation of flues and ventilation for gas appliances of rated output

not exceeding 60kW.

BS 6644 Installation of gas fired hot water boilers of rated inputs between

60kW and 2MW.

BS 5546:1990 Installation of gas hot water supplies for domestic purposes.

BS 6891 Installation of low pressure gas pipework of up to 28mm in domestic

premises.

BS 7206:1990 Specification for unvented hot water storage units and packages.

I/M2 Purging procedures for industrial and commercial gas installations.
I/M11 Flues for commercial and industrial gas fired boilers and air heaters.
I/M16 Notes on installation of gas pipework (excluding 25mm and below).

IGE/UP/10 Pt.1
Edition 2 Installation of Gas Appliances in Industrial and Commercial Premises

NOTE: Consideration should be given to amendments or updates to

the above standards.

GENERAL

INFORMATION

BRITISH

STANDARDS

AND CODES OF

PRACTICE

2

GENERAL AND SAFETY INFORMATION SECTION 1

It is the duty of manufacturers and suppliers of products for use at work to ensure, so far
as is practicable, that such products are safe and without risk to health when properly
used and to make available to users, adequate information about their safe and proper
operation.

Andrews Water Heaters should only be used in the manner and purpose for which they
were intended and in accordance with the instructions in this manual. Although the
heaters have been manufactured with paramount consideration to safety, the basic safety
precautions highlighted in this manual must be observed by the user.

It is imperative that all users of the heater must be provided with all the information and
instruction necessary to ensure correct and safe operation.

Water systems in buildings have been associated with outbreaks of Legionnaires' Disease,
particularly in health care facilities where occupants are significantly more susceptible to
infection.

In recognition of the risks in hospitals, a Code of Practice for the Control of Legionellae
in Health Care premises has been issued by the Department of Health (1991). Codes of
Practice applicable to other premises have been published by other organisations,
principally the Health and Safety Executive (HS)(G70) and the Chartered Institute of
Building Services Engineers (CIBSE, TM13).

All Codes of Practice draw attention to the design and operation of water systems with
reference to avoidance of factors that favour colonisation by Legionellae bacteria. These
factors include stagnation, lukewarm conditions (20ºC to 45ºC) and the accumulation of
debris, scale and corrosion in the base of tanks and calorifiers.

Andrews Water Heaters has commissioned an independent evaluation of their products
to investigate their resistance to build-up of legionellae bacteria.

Experiments were conducted to determine whether, following a substantial challenge by
legionellae pneumophilia, after overnight and stagnation conditions, the system was
rendered free from viable recoverable legionellae. It was found that at 61ºC, following a
challenge of approximately 107 organisms per litre, within one hour, more than 99.999%
of organisms had been killed. After a subsequent stagnation period, sampling did not
reveal any residual contamination. The design of the base of the water heater precludes
legionellae colonisation, even after build-up of debris. The burner positioning ensures
that the water at the bottom of the heater reaches the same, or higher temperature as in
the rest of the heater.

Based on data obtained through experiment, the Andrews Water Heater can be described
as legionellae resistant as it is considered unlikely that, at the temperature tested, the
organism would colonise the water heater and present a possible health risk.

HEALTH AND
SAFETY
REGULATIONS
1993

EFFECTIVENESS
IN COMBATING
LEGIONELLAE

3

ANDREWS MODEL NO.

Storage Capacity l 276 276 276 350

gal 61 61 61 77

Recovery thro' 44ºC/80ºF l/h 749 1149 1517 1808

gal/h 165 253 334 398

Recovery thro' 56ºC/100ºF l/h 600 922 1213 1445

gal/h 132 203 267 318

Heat Input Gross kW 44 66 88 106

Btu/h 150,128 225,192 300,256 361,672

Heat Input Net kW 40 60 80 96

Btu/h 136,480 204,720 272,960 327,552

Gas Flow Rate m

3

/hr 4.09 6.15 8.20 9.88

ft3/hr 144.6 217.2 289.8 349.2

Gas Flow Rates LPG m

3

/hr 1.78 2.54 3.39 4.09

ft3/hr 63 90 120 144.6

Gas Family 1

2

H NATURAL and I

3

LPG

Feed /Flow Connections Rp (BSP) 11⁄

2 1

1

⁄

2 1

1

⁄

2 1

1

⁄

2

Return Connections Rp (BSP)

3

⁄

4

3

⁄

4

3

⁄

4

3

⁄

4

Gas Connection Rp (BSP)

3

⁄

4

3

⁄

4

3

⁄

4

3

⁄

4

Fuel Gas Temperature ºC 132 132 171 171

Fuel Gas Volume m3/hr 110 109 140 164

Max. Working Pressure bar 10 10 10 10

lbf/in

2

150 150 150 150

Min. Working Pressure bar 0.15 0.15 0.15 0.15

lbf/in

2

2.2 2.2 2.2 2.2

Burner Pressure mbar 11.25 11.25 11.25 11.25
Natural Gas ins wg. 4.5 4.5 4.5 4.5

Burner Pressure mbar 25 25 25 25
Propane & Butane ins wg. 10 10 10 10

Injector Diameter mm 2.4 2.9 2.9 3.1

in 0.094 0.114 0.114 0.122

Injector Diameter (LPG) mm 1.65 1.95 1.90 2.1

In 0.064 0.076 0.074 0.082

Weight Empty kg 340 340 345 381

Lb 750 750 760 840

Weight Full kg 636 636 641 727

Lb 1402 1402 1412 1603

Shipping Weight kg 354 354 358 399

Lb 780 780 790 880

Shipping Dimensions Height mm 2110 2110 2110 2110

In 83 83 83 83

Shipping Dimensions Width mm 770 770 770 770

In 30 30 30 30

Shipping Dimensions Depth mm 1210 1210 1210 1210

In 47 47 47 47

Mains Voltage V 220/240 - IP 20

Frequency Hz 50

Fuse A 5

TECHNICAL DATASECTION 2

DIMENSIONS

AND

CLEARANCES

4

CSC39 CSC59 CSC78 CSC93
CSCL39 CSCL59 CSCL78 CSCL93

(Natural Gas)

Control Package:

Pactrol integrated board

intermittent pilot system. White

Rogers 11B79-15 Aquastat with

manual reset ECO.

Gas Valve Honeywell VR8304H.

Alternate: Johnson Controls

G770 Ignition Module (LPG).

Induced Draft Blower:

Fasco 7182-6453C;

230V/50Hz.

Sealed shaft and seams.

TECHNICAL DATA SECTION 2

5

A. Height of Heater mm 1623 1623 1623 1851

In 64 64 64 73

B. Diameter mm 720 720 720 720

In 28 28 28 28

C. Gas Connection mm 355 355 355 355

In 14 14 14 14

D. Cold Inlet mm 530 530 530 530

In 21 21 21 21

E. Optional Front Outlet mm 1307 1307 1535 1535

In 51 51 60 60

F. Height to Centre of Flue mm 2060 2060 1980 2217

In 81 81 78 87

G. Height to Flue Spigot mm 1780 1780 1780 2020

In 70 70 70 80

H. Min. Flue Horizontal mm 840 840 970 970

In 33 33 38 38

Max. Flue Horizontal mm 7000 7000 7000 7000

In 276 276 276 276

I. Min. Flue Vertical mm 1310 1310 1610 1610

In 51 51 63 63

Max. Flue Vertical mm 7000 7000 7000 7000

In 276 276 276 276

J. Electrical Connection mm 1250 1250 1250 1480

In 49 49 49 58

K. Flue Diameter mm 100/150 100/150 130/200 130/200

L. Flue Adaptor mm 95 95

In 4 4

ANDREWS MODEL NO. CSC39 CSC59 CSC78 CSC93

DIMENSIONS
AND
CLEARANCES

Not supplied with

these models

Horizontal or
Vertical Flue

1168mm
Minimum
Service
clearance
with
standard
Anodes.

500mm Recommended

for panel access and
switching. Absolute

min 300mm.

500mm Recommended for

panel access and switching.

Absolute min 300mm.

615mm
Minimum
Service
clearance
with Correx
Anodes.

Adaptor

Cold Water

Inlet 1“

B.S.P.

Drain or Return

3/4” B.S.P.

Ideal Service clearance Dimensions

1125

Horizontal
Flue can
be rotated
360º

Tee & T/P Valve
supplied

Vent from here
if used for Top
Hot Water outlet

‘X’

H

H

K

I

I

Can be
used for
Hot Water
outlet or
can be
capped

Alternative

Hot Water

outlet

If side connection is

used for Hot Water
outlet Air vent must

be fitted at ‘X’

UNVENTED SYSTEM VENTED SYSTEM CSC78 and CSC93 Alternative Flue Systems

CSC39 and CSC59 Alternative Flue Systems

275.0

90.0

725.0 Min.

475.0

300mm

Minimum

N.B. Access of 500mm must be provided

one side for 6 months fan lubrication

LOCATION

INSTALLATIONSECTION 3

THE LAW REQUIRES THAT INSTALLATION IS CARRIED OUT BY A
PROPERLY QUALIFIED PERSON

Installations must be carried out in accordance with Gas safety (Installation and Use)
Regulations 1998, Building Regulations, The Water Supply (Water Fittings) Regulations
1999 and any requirements of the local Gas Authority, Local Authority, Water and Fire
Authorities and the current British Standards and Codes of Practice listed in Section 1.

The location selected for installation of the heater must allow the provision of a
satisfactory flue, adequate air supply, drain facilities and must be well illuminated.

A purpose built boiler room or compartment is strongly recommended.

A manual valve for isolation of the boiler room should be installed in the gas supply; it
should be clearly identified and readily accessible for use at all times.

If a purpose built boiler room is not available, measures should be taken to protect the
heater from damage and prevent any extraneous matter from being stored on or around
the heater. See BS 6644 Clauses 4, 5 and 6 for details.

The heater must not be installed in any location which contains a bed, bath or shower.
There must be easy access to the boiler room and heater at all times.

The water heater must be located in an area where leakage from the tank, water
connections or the combination temperature and safety valve will not result in damage to
the area adjacent to the water heater. When such locations cannot be avoided, a suitable
drain tray must be installed under the water heater. The drain tray must be no deeper
than 38mm (1.5in) and have a minimum length and width of 100mm (4in) wider than
the heater. The drain tray must be piped to an adequate drain using 20mm (0.75in)
diameter pipe, angled for proper drainage.

Access must be provided to the front of the water heater and adequate clearance for it's
servicing and operation.

The floor on which the heater is installed must be flat, level and of sufficient strength to
withstand the weight of the heater when filled with water, and should satisfy the
requirements of the Local Authority & Building Regulations.

Any Combustible material adjacent to the heater must be so placed and shielded as to
ensure that it's temperature does not exceed 66ºC (150ºF).

The minimum clearance to combustibles for the heater Is:
50mm (2in) from the front of the burner access box.

Zero clearance from the air intake boot and vent tubes.
300mm (12in) from the direct vent terminal.

A minimum of 726mm (30 inches) from the burner access panel shall be provided for
inspection and servicing.

All service clearances to the water heater must be maintained as specified in the
CSC Range Installation and Design Guide.

INTRODUCTION

6

INSTALLATION SECTION 3

The installation of the gas supply must conform, depending on it's size, to the
requirements of British Standards and Codes of Practice listed in Section 1 of this manual.

A gas meter will be connected to the service pipe by British Gas plc or it's authorised
contractor.

The meter and service pipe should be checked by British Gas or it's authorised contractor
to ensure that they are adequate to deal with the gas supply to the water heater(s) in
addition to any existing or additional requirements.

CAUTION!
DO NOT APPLY HEAT IN CLOSE PROXIMITY TO THE GAS CONTROL THERMOSTAT
AS THIS WILL RESULT IN DAMAGE OCCURRING TO THE CONTROL.

Fit the gas cock immediately upstream of the gas control valve using a suitable jointing
compound and connect to the gas supply. An inlet nipple and m/f elbow is factory fitted
to the gas control valve to avoid possible damage.

Where the water heater(s) is(are) installed in a boiler house or purpose built
compartment, a manually operated valve for the boiler house must be fitted in
accordance with the Gas Safety (Installation and Use) Regulations 1998. The valve must
be easily identified and readily accessible.

After installation, the system should be pressure tested for soundness and purged in
accordance with BS 6891 or IM/2 and IM/5 as appropriate.

7

GAS SUPPLY

NATURAL GAS

Gas Cock

BSP Thread

U.P.T. Thread

Nipple

Gas Valve

M/F Elbow

Fig 1.

INSTALLATIONSECTION 3

Contact Calor Gas who will provide the appropriate type and size of LPG supply vessel
and ensure it's safe location and installation.

The installation of the gas supply must conform to LPGA Code of Practice, 22 LPG Piping
Systems: Design and installation plus the requirements of British Standards and Codes of
Practice listed in Section of this manual.

Andrews water heaters are unregulated and a second stage regulator must be installed to
give an inlet pressure to the appliance as follows: ( See fig. 2).

PROPANE: 37mbar (14.86 in wg)

BUTANE: 28mbar (11.26 in wg)

When using propane or butane cylinders, connect a minimum number of cylinders as
listed below, together with a manifold before connecting to the union.

Use a minimum pipe size of

3

⁄

4in bore.

Two Cylinders CSC 39 and CSC 59
Three Cylinders CSC 78
Four Cylinders CSC 93

WARNING!
PROPANE AND BUTANE CYLINDERS MUST BE USED AND STORED IN

ACCORDANCE WITH 'THE HIGHLY FLAMMABLE LIQUIDS AND LIQUIFIED
PETROLEUM GASES REGULATIONS 1972', AND SHOULD COMPLY WITH LPGA
CODE OF PRACTICE 7, 'STORAGE OF FULL AND EMPTY LPG CYLINDERS AND
CARTRIDGES.

GAS SUPPLY

PROPANE OR

BUTANE

8

INSTALLATION SECTION 3

9

BULK STORAGE
VESSEL
INSTALLATION

CYLINDER
INSTALLATION

Fig 2.

Regulator Set to
give 37 mbar
(14.86” Wg)
Propane

Pigtail
Assembly

Automatic
change over
device

Nipple

Regulator normally
fitted at tank

To bulk Supply

Installation of
Propane supply

1” Heavy Steel Sleeved
Pipe Through Wall

1” Heavy Steel Sleeved
Pipe Through Wall

Gas emergency
control at entry
point to building

Gas emergency
control at entry
point to building

Steel Liner sealed to
pipe at inside end

Steel Liner sealed to
pipe at inside end

Cylinder regulator Set to give
37 mbar (14.86”) Propane

3/4” Spring loaded gas cock

3/4” Spring loaded gas cock

Propane cylinder must be
outside building

TERMINAL

BLOCK

GREEN

LED

yellow

yellow

SUPPLY :­230Vac / 50Hz

CONSUMPTION :­(RUN STATE)
PRIMARY 110mAac
25VA max.

brown

brown

blue

blue

green/yellow

white

black

green/yellow

O

STAT ECO

yellow

yellow

yellow

orange

orange

orange

ground
terminal

W (FLAME SENSE)

white

G

G/Y

brown

blue

RED
LED

YELLOW

LED

OVERHEAT

PACTROL P.C. BOARD

FLUE
DAMPER
LINK

TIMER
LINK

F-DE T

F-DET

FD 24V

FD 0V

FD2

FD1

GV1

R-PV

BR-MV

Y-PV/MV

FITTING OPTIONS:-

TO FIT TIMER, MOVE TIMER LINK TO 'ON'
POSITION & CONNECT AS SHOWN.

1.

MVPV

24Vac

24Vac

24Vac

230Vac

INDUCED
DRAFT
BLOWER

GV2

GV

ECO2

GAS
VALVE
GROUND

ECO1

STAT

EARTH

HT

24Vac

MAIN

FLAME

FAILURE

Fan L

NO

COM

NC

TIMER (OPTIONAL)

A.P.S.

L

1

1

L

N

E

EMC

FILTER

N

Fan N

MFF2

MFF1

CH2

CH1

TIM1

TIM2

MAINS

ON

FUSE
315mAT

FUSE

4AT

ON/OFF

24Vac
ON/OFF
SWITCH

GVI/PV
GV2/MV
A.P.S.
E.C.O
F.D.

KEY

FLAME
DETECTION
ELECTRODE

24Vac

IGNITION HT
ELECTRODE

FIRST/PILOT GAS VALVE
SECOND/MAIN GAS VALVE
AIR PRESSURE SWITCH
ENERGY CUT-OFF
FLUE DAMPER

2

1

When the Andrews Water Heater is to be connected to a BMS to give a flame failure signal,
the control should be wired as shown.
Te rminals 1 & 2 will give the main flame failure signal.

NORMALLY OPEN
24V AC RELAY

FROM TERMINAL 4 ON RELAY

VOLT FREE
CONTACTS
24V MAX.

INSTALLATIONSECTION 3

External wiring to the water heater(s) must be installed in accordance with current I.E.E.
Regulations for the wiring of buildings and to any Local Regulations that may apply.

The Auto Ignition Heater is designed to operate from a 220/240V, 1Phase supply.
The fuse rating is 5 amps.

The method of connection to the mains electricity supply should facilitate complete
Electrical isolation of the appliance, preferably by use of a fused double pole switch or
fused spur box serving only the heater. The disconnection of the supply shall have a
contact separation of 3mm in all poles.

The point of connection to the mains electricity supply should be readily accessible and
adjacent to the appliance.

Connect the electrical supply the main control panel terminal block via the cable glands in
the base of the control panel. Mains input cable should be 0.75mm

2

, 3 core, and should

be connected to the mains supply as detailed above.

It is recommended that screen cable is used where the volt-free contacts are to be
connected from an external supply. This will eliminate the risk of possible interference
from nearby high voltage cables.

Mains Voltage: 220/240Volts - IP 20
Frequency: 50Hz
Fuse: 5 Amps
Fan Motor: 1.4 Amps

ELECTRICAL

SUPPLY

10

Fig 3.

Wiring diagram for

natural gas appliance.

TRANSFORMER

BL

BL

BK

BK

BK

BK

W

W

W

W

W

O

G/Y

O

M-TH

W

R
Y

BR

GAS VALVE

PILOT

ECO

THERMOSTAT 11B79

MAIN RESET ECO

BLUE

230 VOLTS

RELAY

GROUND

BROWN

230 VOLTS

BKBK

Y/BK

ECO

Y/BK

PANEL
SWITCH

AIR PRESSURE

SWITCH

T'STAT

MOTOR

BLOWER

230 VAC

NO

NO

THS

PV GRD MV SNS IGN

GRD Y

Y

RPV

MV/PV

MV

GAS VALVE

Y

BK

BK

W

W

W

NC

CNO

W

W

PILOT

BR

BL

24 V

Y

Y

O

O

O

T'STAT

3412

PV/MV

PV

MV

M-TH

G/Y

G/Y

G/Y

A1 A2

43 44

33 34

13

3 POLE RELAY

JOHNSON CONTROLS

G730

14

G/Y

NOISE FILTER

PRESSURE
SWITCH

C

NC

NO

Y

Y

Y

Y/BK

O

BR

BR

BR

BL

BL

230 VAC

24 VAC

IGN

M-GND

M-PV/MV

5

THS 5

PV 1

MV 3

M-MV

M-PV

SENSE 4

MOTOR

TERMINAL

BLOCK

TERMINAL

BLOCK

230V/50Hz

Time Clock and/ or
Switch if fitted

INSTALLATION SECTION 3

11

Fig 4.

Wiring Diagram for LPG Appliance

HORIZONTAL

AND VERTICAL

DIRECT FLUE

LENGTHS

INSTALLATIONSECTION 3

Your Andrews Water Heater is a Direct Fan Flued Gas Water Heater where all air for
combustion is obtained from the outside atmosphere and all flue gases are charged to the
outside atmosphere. The flue system is a single coaxial (pipe within pipe) design where
the flue products are discharged through the inside flue tube and the combustion air
supply surrounds the flue surrounded by the outside pipe. The flue system incorporates
both combustion air supply and the flue exhaust. The flue system component which is
outside the building and takes in the combustion air supply and discharges the flue
products (whilst keeping them separate) is referred to as the 'direct flue terminal'.

WARNING!

The direct flue system must be properly installed. Failure to do so could result in property
damage or personal injury. DO NOT install any damaged components. Contact Andrews
Water Heaters for replacement parts. The flow of combustion air must not be restricted.
Keep direct flue terminal openings clear of any objects likely to cause flow restriction.

Direct Flue Terminal

Shall terminate at least 1.5m (5ft) above any forced air inlet located on the same wall.
This provision does not apply to the combustion air intake of a direct flue appliance or
the circulating air inlet and flue gas discharge of listed outdoor appliances.

Shall be installed with at least a 300mm (12in) flue termination clearance from any air
opening into a building.

The bottom of the direct flue terminal shall be located at least 300mm (12in) above
ground.

Consideration should be given to the location of the flue terminal. The flue terminal
should be located where the discharge of flue products does not cause a nuisance.
Consideration should also be given with regard to noise that may be emitted by this flue
system. In all cases the flue termination must meet the requirements of BS6644.

A suitable terminal guard must be fitted if less than 2 mtrs above ground level.

The Andrews Direct Fan Flued Gas Water Heater is supplied with one direct flue kit.
The flue system supplied with this water heater is a coaxial design with the flue discharge
tube on the inside and combustion air supply on the outside. Optional direct flue
components are available that can extend the horizontal length and/or vertical height of
the direct flue to the maximum distances listed in the table below. This water heater
must be installed using the supplied or optional listed components without modification.
Refer to the table on Page 37 for the various vertical and horizontal direct flue system
components.

NOTE! The supplied horizontal flue terminal may be used through outside walls up to
600mm (24in) thick.

Maximum Flue Distances (Horizontal or Vertical)

Number of 90º Elbows Maximum length of straight pipe

(excluding vent terminal) to exterior wall

0 7m (22ft 9in)
1 6m (19ft 6in)
2 5m (16ft 3in)
3 4m (13ft 0in)

NOTE! Each 45º elbow reduces the maximum flue distance by 500mm (19.5in).

IMPORTANT! Do not exceed the flue distances or the number of elbows listed
above. This may cause heater malfunction or an unsafe condition.

FLUE

SYSTEMS

12

INSTALLATION SECTION 3

HORIZONTAL
AND VERTICAL
DIRECT FLUE
LENGTHS

13

Installation Procedure

Determine location of flue exit.

1. The supplied kit includes a horizontal (through the wall) flue terminal, an elbow,
flue connector clamps and 2m (6.5ft) of coaxial flue pipe. The 150mm (6in) diameter
flue system is also supplied with a 200mm (8in) to 150mm (6in) reducer for the
waterheater flue connection. The coaxial flue pipe includes both the flue exhaust
(inside pipe) and combustion air (outside pipe). The coaxial flue pipe may be cut on
the unflared end (end without gasket) as required for the installation.

2. Determine if additional flue components are required for the installation. Refer to the
flue component table below for available optional flue components.

3. Ensure that the flue terminal location complies with requirements described earlier and

the Local Gas Authority.

4. Measure the vertical and horizontal distance from the water heater flue connection to
determine the number of vent flue needed.

Flue Component Table for 150mm (concentric) (6in) Diameter Flue Size
(58.7 kWh 199,999 Btu/h Input Models).

SUPPLIED KIT COMPONENTS

Quantity Flue Length Part Description Part Number

1 90º Elbow E205

1 600mm (24in) Horizontal Flue Terminal E236

1Large Stepped Adaptor Connection Clamp E237

1 200mm (8in) to 150mm (6in) flue reducer E238

INSTALLATIONSECTION 3

FLUE

SYSTEMS

14

Optional Components for 150mm (concentric) (6in) Diameter Flue Size

Quantity Flue Length Part Description Part Number

11 mtr Flue Pipe with clamp E202
11 mtr Cutable Flue Pipe with clamp E203

10.5 mtr Flue Pipe with clamp E204
1 90º Elbow E205
1 45º Elbow E206
1 1360mm (54in) Vertical Flue Terminal E239
1 Flat roof flashing for vertical

flue terminal with adjustable cap E207

1Roof flashing for pitched roofs

150mm (6in) dia vent size E208

1Wall Clamp 150mm (6in) dia. E209

Flue Component Table for 200mm (concentric) (8in) Diameter Flue Size
(88 kWh/300,00 Btu/h and 105.6kW/360,000 Btu/h Input Models.

SUPPLIED KIT COMPONENTS

Quantity Flue Length Part Description Part Number

1 90º Elbow E215
1 600mm (24in) Horizontal Flue Terminal E240
1Large Stepped Adopter

Connection Clamp E237

Optional Components for 200mm (concentric) (8in) Diameter Flue Size

Quantity Flue Length Part Description Part Number

11 mtr Flue Pipe with clamp E212
11 mtr Cutable Flue Pipe with clamp E213

10.5 mtr Flue Pipe with clamp E214
1 90º Elbow E215
1 45º Elbow E216
1 Flat roof flashing for vertical

flue terminal with adjustable cap E217

1Roof flashing for pitched roofs

150mm (6in) dia flue size E218

1Wall Clamp 200mm (8in) dia. E219

INSTALLING THE FLUE TERMINAL

NOTE! The horizontal flue terminal supplied may be used through outside walls up to
600mm (24in) thick.

1. Horizontal flue Terminal (Through the Wall) supplied

a) Cut an opening of at least 165mm (6.5in) diameter through the outside for the

58.7kWh input models or 216mm (8.5in) for the 88kWh and 105.6kWh input models.

b) Slide the flue terminal through the wall opening to the rib closest to the intake air

openings of the terminal even with the outside wall.

c) Slide the outside wall plate over the flue terminal and fasten to the wall with four

screws. Depending on the wall construction, wall anchors may be required to reinforce
the screws.

d) Install inside wall plate on the inside wall and secure with four screws. Depending on

wall construction, wall anchors may be required to reinforce the screws.

INSTALLATION SECTION 3

FLUE
SYSTEMS

15

Wall Anchor

(4 Places)

Wall Anchor

(4 Places)

Screw

(Supplied)

(4 Places)

Screw

(Supplied)

(4 Places)

flue Terminal

Flue Terminal

Outer Wall

Mount Plate

Inner Wall

Mount Plate

Intake Air Openings
(Must Face Ground)

Hole through Wall

Hole through Wall

Fig 5.

Fig 6.

INSTALLATIONSECTION 3

FLUE

SYSTEMS

16

2. Vertical Flue Terminal (Through the Roof - Optional)

a) Determine the exact location where the roof flue terminal will exit the roof, ensuring

the flue system clears all obstructions. For pitched roofs, the flue cap must be the
distance above the roof line as specified, (300mm to base of Flue Clamp, minimum).
The top of the roof terminal may extend up to 760mm (2.5ft) above the roof line as
required.

b) Run the coaxial flue system to the proper distance below the roof sheathing required

for the correct distance of the roof terminal above the roof surface. See the following
sections on installing the rest of the flue system.

c) Cut a minimum 165mm (6.5in) diameter hole for the smaller flue size or a 216mm

(8.5in) minimum diameter hole for the larger flue size centred in the desired location
for the roof terminal. See Fig. 7.

d) Centre the roof flashing over the hole using either the flat roof flashing or universal

flashing for pitched roofs.

e) Slip the storm collar supplied with the roof flashing kit over the outside of the flue

terminal and align with the flue pipe end below roof opening. Insert the terminal into

the flue pipe.
f) Fasten the roof flashing with nails. Seal the flue terminal and flashing to the roof.
g) Install the gasketed clamp around the joint between the flue terminal and flue pipe.

INSTALLING FLUE PIPING SECTIONS

a) The coaxial flue pipe sections are designed to fit tightly together and seal with the

integral flue pipe seal and supplied pipe clamps. No silicone caulk or special tools are
required.

b) All flue sections and fittings come complete with silicone flue pipe gaskets and outside

gasketed pipe clamps for making air tight connections between the flue pipe

connections.
d) Raise the flue pipe to the flue terminal connection with the gasketed end of the flue

pipe towards the flue terminal. Insert the flue pipe into the flue terminal connection

and grasp the end of the flue pipe while twisting and pushing the pipe until inserted

all the way into the flue terminal.
e) Connect the outside pipes together using the gasketed clamps provided. The flue

pipes have ribs located near each end. When the flue piping is connected, the

gasketed clamps shall cover the ribs and joints of the connecting flue tubes. Support

each pipe section with hangers attached to the supporting joists in the wall or ceiling.
f) Continue connecting pipe sections together with clamps and supporting with hangers.

Flat Roof

Flue Terminal

Storm Collar

Roof Flashing
(Nail & Seal
To R oof)

Hole Through Roof

Flue Terminal Pipe

Flue Terminal Pipe

Flue Pipe

(From Water Heater)

Fig 7.

INSTALLATION SECTION 3

FLUE
SYSTEMS

17

Fig 8.

Fig. 9

g) The last pipe section may be cut to fit the distance required to reach the water heater

flue connections. First, install the supplied condensate trap with crimped end into the
gasketed end of the elbow (horizontal flue installations) and clamp the condensate tee
and elbow together. Then install the crimped end of the elbow into the flue
connection of the water heater. On vertical installations, install the the crimped end of
the condensate trap directly onto the water heater flue connection. The 58.7kWh
models require the installation of a flue reducer (supplied) into the water heater flue
assembly before attaching the elbow or condensate trap (vertical flue).

IMPORTANT! In order for the condensate trap to collect and dispose of the
condensate from the flue pipe, the flue system must have a downward slope
of 21mm per metre (0.25in/ft) towards the condensate trap. The condensate trap
must be installed as close as possible to the flue adaptor to prevent condensate
from accumulating and draining into the flue adaptor or blower.

h) Carefully measure the length of straight flue pipe needed, allowing for about 50mm

(2in) insertion into the elbow. Mark the ungasketed end of the pipe to be cut and
carefully make a straight cut on the outside pipe to the desired length. Make sure the
inside tube is not cut. Then cut the inside flue pipe about 50mm (2in) more than the
outside pipe so that the flue pipe protrudes slightly beyond the outside pipe. Connect
the flue pipe and clamp at each end.

i) Use the large clamp supplied in the flue kit with the stepped gasket to seal the elbow

or condensate trap to the blower flue connector. The larger step of the gasket seals
the flue pipe to the cast flue adaptor.

j) Condensate disposal: Connect either a 32mm (1.25in) slip joint drain connection or a

25mm (1in) PVC compression coupling from the condensate trap nipple to 25mm
(1in) PVC piping to a drain or condensate disposal pump. Install a drain trap after the
condensate fitting to seal the flue system.

Note: On all flue installations, for distances over 1.5 metres, we recommend that a

condensate trap is fitted.

Gasket End

Ribs Locked Beneath
Gasketed Clamp

Straight End
(Ungasketed)

Condensate Trap Nipple

Drain Trap

1”(25mm) Compression
Coupling or 1

1

⁄

4” (32mm)

Slip joint Connection

1”(25mm) PVC Piping

To Suitable Drain or
Condensate Disposable Pump

The following notes are intended to give guidance:
Where the heater is to be installed in a room, NO VENTS ARE REQUIRED.

Where the heater is to be installed in a compartment, permanent air vents are required in
the compartment at high and low level. These air vents must either communicate with a
room or internal space or be direct to outside air.

The minimum effective areas of the permanent air vents required in the compartment are
as follows:

Air Vents Areas

Position of Air Vents Air from Room or Internal Space Air Direct from Outside

High Level 10cm2per kW net 5cm2per kW net

Low Level 10cm2per kW net 5cm2per kW net

In a Room or

No Requirement for Ventilation

Internal Space

Note: - Both air vents must communicate with the same room or internal space or
must both be on the same wall to outside air.

Air vents should have negligible resistance and must not be sited in any position where
they are likely to be easily blocked or flooded or in any position adjacent to an extraction
system which is carrying flammable vapour.

Consideration must be given to the position of the high level ventilation opening. A high
level vent must not be sited within 300mm (1ft) measured vertically, of the flue terminal.

Grilles and louvres should be so designed that high velocity air streams do not occur
within the space housing the heater(s).

INSTALLATIONSECTION 3

AIR SUPPLY

AND

VENTILATION

18

IMPORTANT:

1. The effective area requirements specified in the table are related to the maximum heat
input of of the heater(s), and are equivalent to those specified in BS6644 and
IGE/UP/10 Pt.1

2. The free area of the grilles should not be less than the size of the recommended
ventilation opening.

3. The supply of air to a space housing the heater(s) by mechanical means should be:-

(a) Mechanical inlet with natural extraction.
(b) Mechanical inlet with mechanical extraction.

NB!! Natural inlet with mechanical extraction must not be used.

Where a mechanical inlet and mechanical extraction system is used, the design
extraction rate must not exceed one third of the design inlet rate.

All mechanical ventilation systems must be fitted with automatic gas shut off safety
systems which cut off the supply of gas to the heater(s) in the event of failure of either
the inlet or extract fans.

The requirements for air supply by mechanical ventilation are given in BS6644
Clause 19.3 and IGE/UP/10 Pt.1.

The permanent air vents shall be sited away from the extract fans. It may be necessary
to increase the ventilation area to compensate for the extractor fan.

INSTALLATION SECTION 3

AIR SUPPLY
AND
VENTILATION

19

INSTALLATIONSECTION 3

Where extreme conditions of water hardness exist, scale can form in any water heating
equipment, especially when the heater is working under conditions of constant heavy
demand and at high temperatures.

Each water heater is fitted with one or more magnesium anode(s) which protects the
tank from corrosion caused by electrolytic action. Magnesium anodes are sacrificial in
that they corrode as they protect. When the anode has eroded to less than 50% of it's
original diameter, it may not offer protection. The anodes should be inspected annually
and replaced as necessary. Frequency of anode replacement will vary, dependent on
water quality.

Andrews Water Heaters offer Correx

TM

UP powered anodes as an alternative to the
standard magnesium anodes. These anodes do not need maintenance or replacement.
The potentiostat which regulates the current to the CorrexTManode features an indicator
light which shows green to indicate the correct function and red to indicate the
malfunction. These anodes are available as an optional extra on all Andrews heaters.

In hard water areas, scale formation can occur in hot water systems and hot water
heaters and the higher the temperature and volume of water used, the more problematic
the scale build-up can be. Water treatment is normally recommended when the hardness
reaches 100 - 150ppm (7 - 10 degrees Clark) and above. This problem can be minimised
by reducing the water temperature in the heater and by fitting suitable water pre­treatment equipment.

When installing Andrews Water Heaters in hard water areas we would recommend
that a water treatment specialist is consulted.

The heater is fitted with the Hydrojet Total Performance System incorporated in the cold
inlet nipple. The system is designed to increase turbulence and reduce sediment
build-up, reduce thermal stacking and increase delivery.

WATER

QUALITY AND

TREATMENT

20

Hydrojet Inlet Nipple

(Front Cold Inlet

Connection)

Hydrojet System

All models now incorporate the
new Mini Hydrojet system on
cold inlet side connections.

This system ensures water is
directed onto the tank base
which minimises sediment build
up from day one of installation.

Heater Casing

Tank

INSTALLATION SECTION 3

WATER
CONNECTIONS

VENTED SYSTEMS

The water heater must be fed from a cold water feed cistern or static water tank.

A safety valve must be fitted as specified in BS 6644 Clause 9.

The safety valve must be fitted either directly to an upper tank tapping or not further
than 1 metre along the outlet flow pipe of size not less than the safety valve.

There must be no valve separating the heater from the safety valve.

The size of the discharge pipe must be not less than the nominal size of the safety valve
outlet. It should be self-draining and any water discharged must be visible and create no
hazard to persons in or about the building.

A low pressure open vented system can be used or where the natural circulating pressure
is insufficient, pumped circulation can be employed.

The heater must be fitted with an open vent pipe which is not valved and which rises
continuously to the open vent. It should be sized with reference to Technical Data,
BS 6644 Clauses 9 and 10 and CP 342. Local Regulations and Bye-Laws must be
observed when installing the system.

Front Cold inlet / Top Hot outlet water connections / Optional Front Hot outlet
water connection

Select the hot outlet location required, and using a suitable jointing compound blank off
the outlet not required. We recommend that the top hot outlet water connection is used.

Assemble onto the

3

⁄

4 BSP thread, the

3

⁄

4 BSP coupler socket and drain cock using a

suitable jointing compound.

Assemble onto the 11⁄2“ hot water outlet (front) the 11⁄2“ cap end using a suitable
jointing compound.

Water draw-off dead legs should comply with CP 342 Part 2, Table 1 and BS 6700.

NOTE:
When using a secondary return circuit, see Fig 10 for the location of the return
tappings.

It is recommended that all water connections be made to the heater(s) using union
fittings for ease of servicing. Pipe support intervals should comply with CP 342,
Part 2 Table 4.

After Installation of the water system, open the main water supply valve, flush the system
and fill the heater. Open the hot taps to allow air to escape from the system. When the
system is free of air, close the taps and check for leaks at the thermostats, drain cock and
pipe connections on the heater.

21

INSTALLATIONSECTION 3

WATER

CONNECTIONS

VENTED SYSTEMS

Fig 10.

Typical Installation

Vented System

22

Open Vent

Overflow

Hot Water Service

Optional
Hot Water Service

Secondary Return

Check Valve

Cold Water
Inlet Valve

Cold Water
Cistern

Stop Valve

Cold Water Feed

INSTALLATION SECTION 3

WATER
CONNECTIONS

UNVENTED
SYSTEMS

23

Fig 11.

Unvented Systems should be fitted by an Approved Installer

When used in an unvented system, the Andrews water Heater will supply hot water at a
pressure of 3.5bar (51lbf/in

2

), provided that this pressure is available at the mains feed.

During conditions of no-flow, system pressure may rise to a maximum of 6bar (87lbf/in2)
whilst the burner is operating. When testing the system, it is recommended that a
maximum test pressure of 8.6bar (125 lbf/in

2

)is employed.

The heater can be used on unvented hot water storage systems, with the addition of an
Unvented Systems Kit, part number B228 available from Andrews Water Heaters.
See Parts List Pages 38. The Wall mounting assembly is available as an optional extra.

Item C5 must be fitted into C6 and fitted on the hot water outlet nipple (See fig.12).

When assembling items C1 and C2, ensure that the flow arrows marked on the components
are pointing in the direction of flow, i.e. towards the water heater.

The cold water for services may be drawn from the 22mm compression port on item C1(a).
The water pressure at this point will be similar to that available at the hot water outlet of
the water heater. If port (a) is not used, it should be sealed with the blanking plug supplied.

C4

C9
Wall bracket Assembly

C8
Hose Assembly

C6

11⁄

2” Sq Tee

Cold Water
Inlet of
Water Heater

C2 Check Valve/
C3 Expansion Valve

(a)

Balance Cold Water
Take-off
(if required)

C1 Pressure Reducing
Valve / Strainer

Cold Water Inlet

NB. Tees, elbows, stop valves and

pipework not supplied.

OPTIONAL PARTS

C7 Tundish

C5
Temperature/
Pressure
Relief Valve

INSTALLATIONSECTION 3

If higher flow rates are required for the cold water services, a suitable tee fitting should
be fitted to the pipework, upstream of item C1.

The pipework fitted to the tundish outlet should be one size larger than the outlet pipe of
the safety device and should be terminated at a suitable drain.
(See Building Regulations 1992 Approved Document G3).

All fittings and materials must be suitable for use with drinking water and listed in the
current Water Research Centre " Materials and Fittings Directory".

Installation of unvented hot storage water systems must comply with Part G3 of the
Building Regulations 1992.

Typical water service layout for unvented system is shown in Fig 12.

WATER

CONNECTIONS

24

Fig 12.

Cold Water
Inlet Valve

Secondary Return

Optional Hot Water
Service

Check Valve

To Drain

Hot Water Service

Balanced
Cold Water
Take Off

COMMISSIONING SECTION 4

CAUTION! DO NOT OPERATE THE WATER HEATER UNTIL THE STORAGE
VESSEL IS COMPLETELY FILLED WITH WATER, WITH WATER RUNNING FROM
ALL HOT TAPS.

Open the main gas supply cock after all connections to the gas control are completed
and test all connections, using proprietary leak detection fluid.

Filling the Heater with Water

1. Close the water heater drain valve.

2. Open the cold water supply valve.

3. Open several hot water taps to allow air to escape from system.

4. When a steady stream of water flows from the taps. the heater is filled.

5. Close the taps and check for leaks at the drain valve, temperature/pressure relief valve
and the hot and cold water connections.

Draining Water from the Heater

If it becomes necessary to drain the heater, follow the steps below.

1. Depress control panel rocker switch to the OFF position (see Operating).

2. Rotate and partially depress gas control knob clockwise to OFF position.

3. Shut off the gas supply to the heater.

4. Close the cold water supply shut-off valve.

5. Open the drain valve on the water heater.

6. Open a hot water tap to allow air to enter the system.
Refill the water heater as described above.

Lighting the Burner

1. Ensure gas supply is ON.

2. Turn gas control knob to ON position.

3. Using control thermostat, select required water temperature.

4. Move electrical ON/OFF switch to ON. After a delay of about 10 seconds, the burner
will light.

5. Check pilot and main gas connections at gas control valve using leak detection fluid
whilst burner is alight. Turn off, seal any leakages, then re-test.

25

COMMISSIONINGSECTION 4

Shutting Off The Burner

1. For long periods only, (7 days or more) move electrical ON/OFF switch to OFF, then
turn gas control knob to OFF. Turn off gas service cock. For shorter periods, leave
heater under thermostat control.

Checking Main Burner Pressure

1. Turn gas control knob to OFF.

2. Release bleed screw (A) and connect pressure gauge tube to port (A).

3. Light burner as described previously.

4. Remove valve cap from port (B) and adjust pressure using exposed screw in
accordance with data plate. Turn screw clockwise to increase pressure and
counterclockwise to decrease. If possible, check gas rate (see Technical Data) with
meter and watch. Refit valve cap to port (B).

5. Turn gas control to OFF. Remove pressure gauge tube and tighten bleed screw (A).

6. Turn gas control knob to ON and light burner as described above.

Checking Pilot and Burner Flame

1. Visually check that pilot and burner flames are burning properly.

2. The main burner and pilot flame may be viewed through the viewing window on the
front of the combustion air box.

3. Adjustment to the air shutter setting is not normally required for the heater.

4. Some LPG models may be factory pre-set with the burner air shutters closed most of
the way.

5. The burner flames should be blue with yellow tips.

6. A blue/orange flame is characteristic of LPG operation.

If the burners resonate (produce an harmonic noise and vibration, usually with LPG gas),
close down the burner air shutters until the resonance stops. The resonance during
burner operation should only be checked with the front panel held in place, since
resonance may be more pronounced with the front panel off. Ensure flame appearance
is satisfactory after adjusting the burner air shutters as described above.

IMPORTANT! IN THE EVENT OF AN EMERGENCY, TURN OFF GAS AND
ELECTRIC SUPPLY.

26

Fig 13.

A

Gas control
Knob

MV Brown
PV/MV Yellow
PV Red

B

COMMISSIONING SECTION 4

USER'S SAFETY
GUIDE

For your safety read before lighting the appliance.

WARNING

1. Always follow manufacturer's instructions when lighting the appliance. Failure to do so
may result in damage to property, personal injury or loss of life.

2. Before lighting, check all around the appliance area for gas. Be sure to check at low
level because some gas (i.e. LPG) is heavier than air and will settle on the floor.

3. Do not

make any attempt to re-light the appliance if the main burner has
extinguished. Wait at least 5 minutes to allow for any unburnt gas to disperse.
Ventilate the area if possible.

FOR YOUR SAFETY IF YOU SMELL GAS

1. Turn off gas supply and open windows.

2. Do not operate electrical switches.

3. Extinguish any naked flames.

4. Contact gas supplier if the smell of gas persists.

FOR YOUR SAFETY

Do not store or use petrol, aerosol or other flammable vapours or liquids in the vicinity of
this or any other atmospheric gas appliance.

WARNING

Hotter water increases the risk of scalding. Before changing the temperature, refer to the
instruction manual or data label. Hot water can produce third-degree burns in:-

6 seconds at 140ºF (60ºC)
30 seconds at 130ºF (54ºC)

27

OPERATIONSECTION 5

28

When properly installed and adjusted, the heater will require minimal attention. Should it
become necessary to completely drain the heater, follow instructions given in Section 4,
Commissioning.

Whenever the heater is filled with cold water, condensation will form on the storage
vessel surfaces when the burner is lit. This is normal and will disappear when the heater
warms up.

Operating Sequence

1. When the control thermostat senses too-cool water, a signal is sent to the control
sequence unit.

2. When the pilot solenoid opens, gas is allowed to pass to the pilot and simultaneous
ignition begins?

3. When the pilot flame is established, the main gas solenoid is allowed to slowly open
and the main burners or burner is lit.

4. When the control thermostat is satisfied, both pilot and main gas solenoids are closed.

ECO (Energy Cut-Off)

The heater is equipped with an ECO (Energy Cut-Off) device, fitted to the control
thermostat. It is a temperature sensitive switch which opens at high temperature,
shutting off gas to the burners, including the pilot in an overheat condition. When the
water has cooled sufficiently, the manual reset on the ECO needs to be depressed to
allow the heater to be re-lit. If the pilot goes out and is associated with high water
temperature, the ECO is probably operational and the cause of overheating should be
investigated.

Temperature Stratification (Stacking)

When small amounts of hot water are drawn repeatedly, the thermostat responds to each
feed of cold water and activates the main burners. Each time this occurs, more heat may
be put back in the tank than was drawn off. As this continues, water in the upper level
of the tank gets hotter than the thermostat setting. This hotter water does not mix
completely with the cold inlet water, but rises in a 'chimney effect' to the top of the tank.
Many repetitions of this over a short time period results in accumulation of excessively
hot water in the upper part of the tank, even when the thermostat control is within
limits. This is known as stacking.

To counter this condition, an upper thermostat phial is fitted which senses abnormally hot
water and shuts down the main burner until the water cools. Most modern commercial
pipe installations include a circulating pump which keeps hot water moving continuously
throughout the heater. This stabilises temperatures in the water heater tank and
throughout the pipe system.

SERVICING SECTION 6

29

Servicing must be carried out by a properly qualified person.

Whilst giving these instructions for the care of the Heater, it is recommended that checks
are carried out by the installer or local gas authority, at least annually. Ensure good
ventilation by keeping the heater free of extraneous materials and clear of dust and lint.
Keep pipework, flue and tops of heaters clear of any combustible materials. A water
softener or lime inhibitor should be employed in hard water areas. The heater should be
inspected every few months via the hand hole cleanout and lime or silt deposits removed.
Failure to do so will shorten heater life and may invalidate the warranty.

NOTE! The cleanout hole gasket must be renewed whenever the cover is removed.

Before servicing, carry out the following operations.

1) Turn off the gas service cock.

2) Turn off the cold water supply to the heater.

3) Turn on the hot water draw-off taps served by the water heater, or, for multiple
installations, turn off the hot water outlet connection valve and secondary return valve.

4) Drain down using the drain valve on the heater.

Annual checks of the ignition systems, temperature controls and any other controls are
necessary to ensure continued safe and efficient operation.

The entire combustion system must be sealed for this water heater to function correctly.
Ensure that the burner access panel is kept tightly sealed. The combustion air supply pipe
at the rear of the heater must be tightly clamped to the vent adopter and combustion air
box boot. Replace any damaged parts.

The entire venting system and combustion air supply must be inspected at least annually
for integrity of all joints and gaskets.

BLOWER MOTOR BEARINGS

Every six months lubricate the blower motor bearings. Apply four drops of SAE 20 motor
oil to the ports of the front and rear motor bearings.

INTRODUCTION

PRE-SERVICE
OPERATIONS

ANNUALLY

SIX MONTHLY

SERVICINGSECTION 6

Annually, remove the main burner rack assembly to clean orifices and related parts of any
dirt or other foreign matter. Inspect the burner ports for obstructions or debris and clean
with a wire brush, vacuum, or use a mild detergent to clean as necessary. Inspect the
pilot. Carefully clean the electrode and flame sense rod with emery cloth. The spark
electrode (rod closest to the pilot hood) gap should be 1/8 in.

NOTE: It is vital for proper and safe operation that the main burner rack is replaced in it's
original position.

To remove the burner rack assembly, follow the procedures outlined below.

a) Shut off the gas and electrical supply to the heater.
b) Remove the pilot tube fittings at the gas valve and combustion box.
c) Disconnect wires to gas valve. Open control box and disconnect pilot spark and flame

sense wires. Remove the wire raceway cover below the control box.
d) Disconnect the gas pipe union below the gas valve.
e) Remove the three screws securing the gasketed manifold pipe flange on the left side of

the combustion box.
f) Remove the burner access panel from the front of the combustion box.
g) Carefully remove and push the pilot wire grommet into the combustion box with the

pilot wires.
h) Disconnect the pilot tube fitting on the inside bulkhead fitting of the combustion box.
i) Unthread the gas pipe assembly from the manifold inside the combustion box.
j) Remove the screw securing the burner rack on the top right panel of the combustion

box.

k) Slide out the burner rack assembly.

To re-install the burner rack, reverse the above procedures.

The gas control valve should be checked and cleaned. Remove any debris from the valve
inlet filter using a soft brush or by blowing with low pressure air.

After servicing, Check:-

1. Soundness of any gas joints broken or disturbed and seal any leaks.

2. Burner pressure/gas rate at maximum thermostat setting.

3. Operation of heater is correct. Reset controls to user's requirements.

Magnesium sacrificial anode(s) is (are) fitted to the top of the storage vessel. The anode
will prevent corrosion of the storage vessel. Anode condition should be checked annually
and replaced if excessive wear is present.

1. Withdraw each anode using an

11

⁄16 in AF socket spanner. A new anode measures

21mm diameter.

2. An anode should be replaced, if, at any point along it's length, the diameter is reduced

to half, or less of original. Particular attention should be paid to the ends.

3. If the anode is encrusted with limescale, it should be either wire brushed to reveal

bright metal or replaced.

Where Correx

TM

anodes are fitted, no maintenance is necessary.

BURNER

ASSEMBLY

GAS CONTROL

VALVE

MAGNESIUM

ANODES

30

SERVICING SECTION 6

Check the condition and operation of this component at least once a year to ensure
it is free from limescale deposits.

Lift the lever at the top of the valve several times until the valve seats properly without
leakage and operates freely.

Clean or replace as necessary.

The storage vessel should be checked and cleaned annually

Scale formation in the base of the vessel may occur, particularly in hard water areas and
is normally associated with high usage and high water temperatures. It is characterised by
a rumbling noise when the main burner is lit. Scale formation in the base of the vessel
will affect the efficency of the water heater and reduce the life of the storage vessel.

It should be noted that the failure of the storage vessel due to scale formation on
the base will not be covered by the terms of the warranty.

Any scale formation which cannot be removed by normal means of cleaning should be
removed by chemical descaling. See below.

Descaling

When descaling the heater, attention is drawn to the following guidelines.

CAUTION!
DUE TO THE CORROSIVE NATURE OF DESCALING FLUID, IT IS ESSENTIAL THAT
SUITABLE PROTECTIVE CLOTHING IS USED AND ADEQUATE VENTILATION
AVAILABLE.

1. Turn gas control to OFF and isolate gas supply.

2. Close water inlet valve and drain heater tank.

3. Remove magnesium anode(s). It is recommended that new anode(s) is (are) fitted.

4. Add suitable hydrochloric acid based descale fluid. The requirement is normally
10 litres or more dependent on amount of limescale present.

5. After a minimum of one hour, restore gas supply and turn on main gas burner for 2
minutes maximum.

6. Isolate gas supply and drain descale fluid through drain port.

7. Open cold water feed valve and fill heater tank.

8. Drain and flush out heater for 20 minutes minimum.

9. Replace anode(s).

10. Restore gas supply and re-light heater.

IMPORTANT

Remove Correx

TM

anodes if fitted and plug off the connections using 3/4” BSP plugs.

Re-fit the CorrexTManodes when the descaling operation is complete.

Re-light and carry out commissioning checks as detailed in Section 4, Commissioning.
Set the thermostat control to the required user setting.

31

RESTART

COMBINED
TEMPERATURE
AND PRESSURE
RELIEF VALVE

CLEANING
THE
STORAGE
VESSEL

FAULT FINDINGSECTION 7

32

FAULT ACTION

WATER DOES (a) Check gas service cock is open.
NOT GET HOT (b) Check water valves are open.

(c) Check thermostat setting. (reset to higher temperature)

HEATER SOOTING, (a) Check gas burner. If possible, check heat input with meter
YELLOW FLAME and watch.
(POOR (b) Clean burners and injectors.
COMBUSTION) (c) Flue obstruction. Clean flue ways.

(d) Check flue and termination position.
(e) Check for correct ventilation.

WATER (a) Reset thermostat to lower temperature.
TEMPERATURE (b) Thermostat faulty. Check and replace if necessary.
TOO HIGH (c) Main gas valve not closing. Clean or replace.

NOT ENOUGH (a) Check gas pressures at burner and at gas inlet to heater.
HOT WATER (b) Check amount of water being used against recovery rate

given on data plate. If usage too high, more heating
capacity needed.

WATER DRIPPING (a) Check if this stops when water in heater is hot. If yes, then
FROM BASE OF condensation is the problem caused by incorrectly designed
HEATER flue or by tank cooling excessively, i.e. more hot water

being used than recovery rate of heater. If so, more
heating capacity needed.

(b) If water continues to drip when heater is hot, problem is

leaking joint or storage vessel.

FAULT FINDING SECTION 7

33

FAULT ACTION

RUMBLING NOISE (a) Scale formation in heater, consult water treatment

specialist. Heater must be descaled and suitable water
treatment provided to avoid re-occurrence.

CONTINUOUS (a) Check gas service cock is open.
IGNITION (b) Check gas control knob is ON.
NO PILOT FLAME (c) Check ECO for failure.

PILOT LIGHTS BUT (a) Main gas valve not energised. Check for loose contacts.
MAIN BURNER (b) Check for 24V AC at intermittent pilot ignition.
DOES NOT Replace control if faulty.

(c) Check for 24V AC at main gas valve terminals. Replace

valve if faulty.

NO IGNITION AT (a) Electrical ON/OFF switch is not ON.
PILOT (b) Thermostat set too low.

(c) Power to unit interrupted.

PARTS LIST AND ILLUSTRATIONSSECTION 8

34

A5

A4

A3

A9

A19

A1

A16

A17

A18

C4

C5

C3

A2

A7

A6

C6

A8

A13

A15

A20

A10

A12

A11

A14

B2

C2

B3

B7

C1

B4

B1

B5

B6

A21

PARTS LIST AND ILLUSTRATIONS SECTION 8

35

Model
Ref.

CSC39 CSC59 CSC78 CSC93

Part Numbers Description Qty

A1 E221 E221 E221 E221 Fan Motor Assembly 1
A2 C288 C288 C288 C289 Sacrificial Anode 4
A3 E223 E223 E223 E223 Flue Baffle 9
A4 C991 C991 C991 C991 Control Circuit Board 1
A5 C521 C521 C521 C521 On / Off Switch 1
A6 E193 E194 E195 E196 Data Badge Nat. Gas 1
A7 C534 C534 C534 C534 Nipple 1

1

⁄2” BSP 1

A8 E050 E050 E050 E050 Hydrojet Cold Inlet 1

1

⁄

2” BSP 1

A9 E631 E631 E631 E632 Pressure Switch 1
A10 C299 C299 C299 C299 Cleanout Pad Seal 1
A11 C300 C300 C300 C300 Cleanout Pad 1
A12 C301 C301 C301 C301 Cleanout Pad Cover 1
A13 C247 C247 C247 C247 Drain Tapping Connector 1
A14 C381 C381 C381 C381 Drain Cock BS2879

3

⁄4”1

A15 C103 C103 C103 C103 Socket Coupler

3

⁄4”1
A16 E346 E346 E346 E346 Fan Motor 1
A17 E593 E593 E593 E593 Capacitor 1
A18 E586 E586 E586 E586 Fan Mounting Flange 1
A19 E671 E671 E671 E671 Nipple 1

1

⁄2”x 12” BSP 1
A20 E673 E673 E673 E673 Bulkhead Union 1
A21 E727 E727 E727 E728 Air Vent Pipe 1
B1 E225 E225 - - Burner bar 5

--E225 E225 Burner bar 7
B2 E226 E226 E226 E226 Pilot Assembly 1
B3 E227 - - - Injector 2.4mm Nat. Gas 5

- E228 - - Injector 2.9mm Nat. Gas 5

--E228 - Injector 2.9mm Nat. Gas 7

- E229 Injector 3.1mm Nat. Gas 7

E230 - - - Injector 1.65mm LPG 5

- E231 - - Injector 1.95mm LPG 5

--E232 - Injector 1.90mm LPG 7

- E233 Injector 2.1mm LPG 7
B4 E234 E234 E234 E234 Gas Valve 1
B5 C498 C498 C498 C498 Gas Cock

3

⁄4” BSP FxF 1

B6 E235 E235 E235 E235 Control Thermostat with

Remote Phial and ECO 1
B7 E386 E386 E386 E386 Combustion Box Cover 1
C1 E348 E348 E348 E348 Gas Valve Assembly complete with fittings LPG 1
C2 E349 E349 E349 E349 Pilot Assembly (PSE-43L) LPG 1
C3 E350 E350 E350 E350 Transformer LPG 1
C4 E351 E351 E351 E351 Relay LPG 1
C5 E352 E352 E352 E352 Ignition Control Jc G770 LPG 1
C6 E365 E366 E367 E368 Data Badge LPG 1

PARTS LIST AND ILLUSTRATIONSSECTION 9

36

200mm (8in) Flue Kit

150mm (6in) Flue Kit

13

1

14

10

12

11

8

2

7

5

3

9

12

1

13

9

11

10

7

2

6

5

3

8

6

Ref. Part No. Description Qty

1 E205 90˚ Elbow with Clamp
2 E202 1 mtr Flue with Clamp
3 E236 Horizontal Flue Terminal
4 E209 Wall Clamp (Not Shown)
5 E237 Large Stepped Adaptor Connection Clamp
6 E238 200mm (8in) to 150mm (6in) Reducer
7 E203 1 mtr Cutable Flue with Clamp
8 E204 0.5 mtr Flue with Clamp
9 E239 Vertical Flue Terminal
10 E210 Condensate Trap Tee
11 E207 Flat Roof Plate
12 E208 Angled Roof Plate
13 E105 Horizontal Flue Outlet Terminal Guard
14 E206 45˚ Elbow with Clamp

PARTS LIST AND ILLUSTRATIONS SECTION 9

37

200mm (8in)
Flue Kit

Ref. Part No. Description Qty

1 E215 90˚ Elbow with Clamp
2 E212 1 mtr Flue with Clamp
3 E240 Horizontal Flue Terminal
4 E219 Wall Clamp (Not Shown)
5 E237 Large Stepped Adaptor Connection Clamp
6 E213 1 mtr Cutable Flue with Clamp
7 E214 0.5 mtr Flue with Clamp
8 E241 Vertical Flue Terminal
9 E220 Condensate Trap Tee
10 E217 Flat Roof Plate
11 E218 Angled Roof Plate
12 E630 Horizontal Flue Outlet Terminal Guard Extended
13 E216 45˚ Elbow with Clamp

150mm (6in)
Flue Kit

Note: Extra lengths of flue tubing can be supplied to suit each installation requirement.
Also extra 90˚ and 45˚ elbows can be supplied.

Note: Extra lengths of flue tubing can be supplied to suit each installation requirement.
Also extra 90˚ and 45˚ elbows can be supplied.

PARTS LIST AND ILLUSTRATIONSSECTION 9

38

Unvented System kit

Ref. Part No. Description Qty

B228 Unvented Systems Kit Complete 1
C1 C784 Combined Reducing Valve/Strainer 1
C2 C785 Check Valve 1
C3 C786 Expansion Valve 1
C4 C782 Expansion Vessel (25 Litre) 1
C5 E242 Temperature/Pressure Relief Valve 11⁄2”1
C6 C856 11⁄

2” Square Equal Tee 1

C7 E326 Tundish from Expansion Valve and T/P Valve 1

B173 Wall Mounting Kit (Optional)
C8 C788 Hose Assembly 1
C9 C787 Wall Bracket Assembly 1

C1

C8

C9

C2

C3

C7

C5

C4

C6

CSC39, 59, 78 & 93 Parts List

Wednesbury One,
Black Country New Road
Wednesbury,
West Midlands WS10 7NZ
Te l: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.andrewswaterheaters.co.uk

10/05