Combi C30 & C35
Installation and Servicing Instructions
FAN POWERED HIGH EFFICIENCY
MODULATING DOMESTIC CONDENSING
GAS COMBINATION BOILER
When replacing any part on this appliance, use only spare parts that you can be
assured conform to the safety and performance specication that we require.
Do not use reconditioned or copy parts that have not been clearly authorised by Keston.
For the very latest copy of literature for specication and maintenance practices visit our website
www.keston.co.uk where you can download the relevant information in PDF format.
September 2017
UIN 215348 A05
ERP DATA
MODEL
SYMBOL UNITS 30 35
Condensing Boiler n/a n/a yes yes
Low Temperature Boiler n/a n/a no no
B1 Boiler n/a n/a no no
Cogeneration Space Heater n/a n/a no no
Equipped with a Supplementary Heater n/a n/a no no
Combination Heater n/a n/a yes yes
Nominal Heat Output for Space Heating
Full Load P
Part Load P
Auxiliary Electricity Consumption
Full Load el
Part Load el
Standby P
Seasonal Space Heating Energy Efciency
Full Load
Part Load
Standby Loss P
Ignition P
4 kW 24.3 24.3
1 kW 8.0 8.0
max kW 0.032 0.029
min kW 0.013 0.013
SB kW 0.005 0.005
ƞ
4
ƞ
1
stby kW 0.050 0.050
ign kW 0 0
% 90.0 90.0
% 98.7 98.7
Emissions NO
Annual Energy Consumption Q
Sound Power Level, Indoors L
Domestic Hot Water
Q
ƞ
Q
AEC kWh 16 16
AFC GJ 6 6
x mg/kWh 28 33
HE GJ 75 75
WA dB 46 44
elec kWh 0.075 0.074
WH
fuel kWh 7.750 7.700
% 78 78
2
Installation and Servicing
PRODUCT FICHE
KESTON COMBINATION BOILER
Ideal Boilers
ERP DATA
SYMBOL UNITS MODEL
30 35
Condensing boiler Yes
Seasonal Space heating efciency class A
Rated heat output kW 24
Seasonal space heating energy efciency
Annual energy consumption Q
Sound power level, indoors L
Water heating energy efciency class A
Seasonal Space Heating Energy Efciency of the Boiler *%
Temperature control (from che of temperature control) %
Class I Class II Class III Class IV Class V Class VI Class VII Class VIII
1% 2% 1.5% 2% 3% 4% 3.5% 5%
ƞs
HE GJ 75
WA dB 46 44
% 94
A
B
Solar Contribution (from che of solar device)
Collector Size
(in m2)
= (‘III ’x + ‘IV ’ x ) x 0.9 x ( / 100 x =
Seasonal Space Heating Energy Efciency of Package
Seasonal Space Heating Energy Efciency Class of Package
Tank Volume
(in m3)
Collector
Efciency
(in %)
Tank rating
A* = 0.95
A = 0.91
B = 0.86
C = 0.83
D-G = 0.81
TOTAL: A+B+C=
%
C
%
GG F E D C B A A+ A++
< 30% ≥ 30% ≥ 34% ≥ 36% ≥ 75% ≥ 82% ≥ 90% ≥ 98% ≥ 125% ≥ 150%
The energy efciency of the package of products provided for in this document may not correspond to its actual energy efciency once installed in a
building, as the efciency is inuenced by further factors such as heat loss in the products in relation to the building size and its characteristics
Installation and Servicing
A+++
3
4
Installation and Servicing
NOTES FOR THE INSTALLER
FOR ANY TECHNICAL QUERIES PLEASE RING THE KESTON
INSTALLER/TECHNICAL HELPLINE : 01482 443005
NOTE. BOILER RESTART PROCEDURE -
Press the RESTART button. The boiler will repeat the ignition sequence if a heat demand is present.
DOCUMENT AMENDMENTS
Relevant Installation changes implemented in this book from Mod Level ....... A04 (Jun 17) to A05 (Sept 17)
Page 11 - Section 1.7 - Location of Boiler
Compartment Installation - new para added regarding Braces.
Page 12 - Section 1.8 - Gas Supply
New para added checks to gas valve connections.
Page 14 - Section 1.14 - System Requirements
Domestic Hot Water - New item 4.
Page 24 - Section 2.12 - Assembly Practice
Update to “Important” note.
Page 39 Menu Operaitons
Update to various screen displays. Was showing “rpm” gures. Now showing “%” gures.
Page 67 - Spare Parts
Note added ref to Propane Boiler.
Installation and Servicing
Keston reserve the right to vary specication without notice
5
6
Installation and Servicing
CONTENTS
1 GENERAL .................................................................... 8
1.1 Introduction ................................................................10
1.2 Operation ...................................................................10
1.3 Safe Handling ............................................................. 10
1.4 Optional Extra Kits .....................................................10
1.5 Safety ......................................................................... 11
1.6 Safe Handling Of Substances .................................... 11
1.7 Location Of Boiler ...................................................... 11
1.8 Gas Supply ................................................................. 12
1.9 Water Circulation System ........................................... 12
1.10 Boiler Control Interlocks .............................................12
1.11 Electrical Supply ......................................................... 12
1.12 Condensate Drain .................................................... 12
1.13 Boiler Dimensions, Services & Clearances ................ 13
1.14 System Requirements - Central Heating .................... 14
1.15 System Balancing ......................................................15
1.16 Water Treatment......................................................... 15
2 INSTALLATION .........................................................16
2.1 Boiler Assembly - Exploded View ...............................16
2.2 Unpacking .................................................................. 17
2.3 Flue System ............................................................... 18
2.4 Flue Installation Example Keston Combi C30 ............ 20
2.5 Flue Installation Example Keston Combi C35 ............ 20
2.6 Flue Termination Position ........................................... 21
2.7 Installing The Boiler .................................................... 22
2.8 Wall Mounting Template ............................................. 22
2.9 Preparing The Wall .....................................................23
2.10 Fitting The Wall Mounting Plate ................................. 23
2.11 Mounting The Boiler ................................................... 23
2.12 Assembly Practice ...................................................... 24
2.13 Fitting The Flue Sleeve .............................................. 25
2.14 Condensate ................................................................ 26
2.15 Connections & Filling .................................................28
2.16 Electrical Connections ................................................ 30
2.17 Installer Wiring ...........................................................30
2.18 External Wiring ........................................................... 31
2.19 Replacing Pre-Fitted Mains Cable .............................31
2.20 CH Operation ............................................................. 32
2.21 The Weather Compensation Kit ................................. 33
2.22 Wiring Diagram ..........................................................34
2.23 Commissioning And Testing ....................................... 35
2.24 Initial Lighting ............................................................. 36
2.25 The Display ................................................................ 37
2.26 General Checks .........................................................41
2.27 Restart Procedure ...................................................... 42
2.28 Handing Over ............................................................. 42
3 SERVICING ............................................................... 43
3.1 Servicing Schedule ...................................................43
3.2 Boiler Front Panel Removal / Replacement ............... 44
3.3 Fan And Venturi Assembly Removal And Cleaning ....44
3.4 Burner Removal And Cleaning ................................... 45
3.5 Cleaning The Condensate Trap/Siphon ..................... 45
3.6 Cleaning The Heat Exchanger ................................... 46
3.7 Reassembly ...............................................................46
3.8 Replacement Of Components .................................... 47
3.9 Fan Replacement ....................................................... 47
3.10 Burner Injector Replacement .....................................48
3.11 Burner Replacement .................................................. 48
3.12 Return Thermistor Replacement ................................ 49
3.13 Ignition Electrode Replacement ................................. 49
3.14 Flame Detection Electrode Replacement ................... 50
3.15 Spark Generator Replacement ..................................50
3.16 Gas Control Valve Replacement ................................ 50
3.17 Diverter Valve Actuator Replacement ........................51
3.18 Condensate Trap/Siphon Replacement ..................... 51
3.19 PCB Replacement ...................................................... 52
3.20 Draining The Boiler ....................................................53
3.21 DHW Flow Turbine Sensor Replacement .................. 53
3.22 Pressure Gauge Replacement ................................... 53
3.23 Safety Relief Valve Replacement ............................... 54
3.24 Pump Automatic Air Vent Replacement .....................54
DHW Filter & Flow Regulator Cleaning/Replacement .....
3.25
3.26 Diverter Valve Body Assembly Replacement ............. 55
3.27 DHW Plate Heat Exch. Replacement ......................... 55
3.28 Pump Head Replacement .......................................... 55
3.29 CH Water Pressure Switch Replacement .................. 56
3.30 Flow Thermistor Replacement ................................... 56
3.31 Heat Engine Replacement ......................................... 57
3.32 Expansion Vessel Recharging & Replacement .......... 58
4 FAULT FINDING ........................................................ 59
4.1 Fault Finding Chart Main Menu .................................. 59
4.2 Overheat Lockout ....................................................... 61
4.3 Ignition Lockout .......................................................... 61
4.4 Flame On Before Gas Valve On ................................. 62
4.5 Low Water Pressure ................................................... 62
4.6 Flame Loss ................................................................. 62
4.7 Fan Fault .................................................................... 63
4.8 Flow Thermistor Fault ................................................63
4.9 Return Thermistor Fault ............................................. 63
4.10 Outside Sensor Fault .................................................64
4.11 No CH Operation But DHW Works OK ...................... 65
4.12 No HW But CH On ..................................................... 66
4.13 No Display .................................................................. 66
54
Installation and Servicing
5 SPARE PARTS .......................................................... 67
6 BENCHMARK & COMMISSIONING ......................... 68
7
SECTION 1 - GENERAL
Table 1 - General Data
30 35
Gas supply 2H - G20 - 20mbar
Gas Supply Connection 15mm copper compression
Injector Size mm 4.65 4.9
Inlet Connection DHW 15mm copper compression
Outlet Connection DHW 15mm copper compression
Flow Connection CH 22mm copper compression
Return Connection CH 22mm copper compression
Flue Terminal Diameter mm (in) 50 (nominal)
o
Average Flue Temp-Mass Flow Rate (DHW) 68
CO2 Content (± 0.7) Max. DHW
Min. CH
Maximum Working Pressure (Sealed Systems) bar (lb/in
Maximum Domestic Hot Water Inlet Pressure
Minimum Domestic Hot Water Inlet Pressure*
bar (lb/in2) (kPa)
bar (lb/in2) (kPa)
Minimum DHW Inlet Pressure to operate at 0.6
bar system pressure
Electrical Supply 230 V ~ 50 Hz.
Power Consumption W 101 114
Fuse Rating External : 3A Internal : T4A HRC L250 V
Water content CH litre (gal) 1.2 (0.26)
DHW litre (gal) 0.5 (0.11)
Packaged Weight kg 34.40 34.50
Maximum Installation Weight kg 31.40 31.50
Boiler Casing Size Height mm 700
Width mm 395
Depth mm 278
2
) 2.5 (36.3)
bar 0.5
*Required for maximum ow rate. Boiler operates down to 2 l/min DHW delivery
** In areas of low water pressure the DHW restrictor can be removed
C - 13g/s 73ºC - 15g/s
9.3% 9.5%
8.8% 8.9%
10.0 (145) (1000)
1.3 (18.9) (130) 1.3 (18.9)** (130)
Table 2 - Performance Data - Central Heating Table 3 - Performance Data - Domestic Hot Water
Boiler Input : Max. Min. 30 Min. 35
Boiler Input ‘Q’ Nett CV kW 24.3 6.1 7.1
Gross CV kW 27.0 6.7 7.9
3
Gas Consumption m
Boiler Output :
Non Condensing 70
Condensing 40
Seasonal efciency* SEDBUK 2005
NOx Classication CLASS 5
o
C Mean Water temp. kW 24.2 6.1 7.1
o
C Mean Water temp. kW 25.6 6.4 7.5
/h 2.512 0.623 0.734
3
/h) (89) (22) (25.9)
(ft
91.1%
SEDBUK 2009
89.6%
91.1%
89.6%
Maximum DHW Input : 30 35
Nett CV kW 30.4 35.4
Gross CV kW 33.7 39.3
3
Gas Consumption m
Maximum kW 30.3 35.3
DHW Flow Rate l/min 12.4 14.5
at 35°C temp. rise. (gpm) (2.8) (3.2)
DHW Specic Rate l/min 14.5 16.9
/h 3.135 3.658
3
/h) (111 ) (129)
(ft
(gpm) (3.2) (3.7)
* The value is used in the UK Government’s Standard Assessment Procedure (SAP) for energy rating of dwellings. The test data from
which it has been calculated have been certied by a notied body.
Note. Gas consumption is calculated using a caloric value
of 38.7 MJ/m3 (1038 Btu/ft3) gross or 34.9 MJ/m3 (935 Btu/
ft3) nett
To obtain the gas consumption at a different caloric value:
a. For l/s - divide the gross heat input (kW) by the gross
C.V. of the gas (MJ/m
3
)
b. For Btu/h - multiply the gross heat input (kW) by 26.8
3
c. For ft
/h - divide the gross heat input (Btu/h) by the gross
C.V. of the gas (Btu/ft3)
3
d. For m
/h - multiply l/s by 3.6
Key to symbols
GB = United Kingdom IE = Ireland (Countries of destination)
PMS = Maximum operating pressure of water
C13 C53
= A room sealed appliance designed for connection via ducts
to a horizontal or vertical terminal, which admits fresh air to
the burner and discharges the products of combustion to the
outside through orices which, in this case, are separate.
The fan is up stream of the combustion chamber.
I
=
An appliance designed for use on 2nd Family gas, Group H only.
2H
8
Installation and Servicing
SECTION 1 - GENERAL
KESTON COMBI C30 & C35
Natural Gas only
Boiler size G.C. Appliance No. PI No.
(Benchmark No.)
30 47-930-07 86CR18
35 47-930-08 86CR18
Destination Country: GB, IE
For GB, to comply with Building Regulations Part L1 (Part 6 in Scotland) the boiler should be tted in accordance with the
manufacturer’s instructions. Self-certication that the boiler has been installed to comply with Building Regulations can be
demonstrated by completing and signing the Benchmark Commissioning Checklist.
Before installing this boiler, read the Code of Practice sheet at the rear of this book.
BENCHMARK COMMISSIONING CHECKLIST DETAILS
Boiler Page
Make and model ......................................................... 9
Appliance serial no. on data badge .......... Front Cover
SEDBUK No. % .......................................................... 8
Controls
Time and temperature control to heating .................31
Time and temperature control to hot water .............31
Heating zone valves ................................................ n/a
TRV’s........................................................................ 12
Auto bypass ............................................................. 12
Boiler interlock .......................................................... 12
For .................................................................... all boilers
Flushing to BS.7593 ................................................. 14
Inhibitor ....................................................................15
Central heating mode
Heat input ...................................................to be calculated
Page
Burner operating pressure ...................................... n/a
Central heating ow temp. ...........measure and record
Central heating return temp. ........measure and record
For combination boilers only
Scale reducer ........................................................... 15
Hot water mode
Heat input ............................................to be calculated
Max. operating burner pressure .............................. n/a
Max. operating water pressure ........ measure & record
Cold water inlet temp ...................... measure & record
Hot water outlet temp. ..................... measure & record
Water ow rate at max. setting ........ measure & record
For condensing boilers only
Condensate drain ..................................................... 26
For all boilers: complete, sign & hand over to customer
For assistance see Technical Helpline on the back page
NOTE TO THE INSTALLER:
THE BENCHMARK COMMISSIONING
CHECKLIST AND LEAVE THESE
INSTRUCTIONS WITH APPLIANCE
Installation and Servicing
COMPLETE
9
SECTION 1 - GENERAL
1.1 INTRODUCTION
The Keston Combi boiler is a wall mounted, full sequence,
automatic spark ignition, low water content, fanned ue, high
efciency, condensing, combination gas boiler.
Note. Due to the high efciency of the boiler a plume of water
vapour will form at the terminal during operation.
Central heating (CH) output is fully modulating with a range of:
30 6.1 to 24.2kW
35 7.1 to 24.2kW
Instantaneous domestic hot water (DHW) output is also fully
modulating with a maximum of :
30 30.3kW
35 35.3kW
The boiler is supplied fully assembled with DHW plate heat
exchanger, diverter valve, circulating pump, pressure gauge,
safety valve and CH expansion vessel.
Variable CH and DHW temperature controls are tted on the user
control and the boiler features a DHW preheat facility.
The boiler includes as standard:
- Automatic bypass
- Boiler frost protection
- Daily pump and diverter valve exercise.
- Weather Compensation Kit
The boiler casing is of white painted mild steel with a white
polymer front panel.
The boiler temperature controls are visible located in the control
panel on the front of the boiler.
The heat exchanger is manufactured from cast aluminium.
The boiler is suitable for connection to fully pumped, sealed
heating systems ONLY. Adequate arrangements for completely
draining the system by provision of drain cocks MUST be
provided in the installation pipework.
Pipework from the boiler is routed downwards.
Data Plate
The boiler model and serial number can be located on the bottom
of the boiler casing, shown in Frame 1 - Water & Gas Connection
Diagram.
At low DHW draw-off rates the maximum temperature may
exceed 65ºC.
The boiler features a comprehensive diagnostic system which
gives detailed information on the boiler status when operating,
and performance of key components to aid commissioning and
fault nding.
1.3 SAFE HANDLING
This boiler may require 2 or more operatives to move it to its
installation site, remove it from its packaging base and during
movement into its installation location. Manoeuvring the boiler
may include the use of a sack truck and involve lifting, pushing
and pulling.
Caution should be exercised during these operations.
Operatives should be knowledgeable in handling techniques
when performing these tasks and the following precautions should
be considered:
• Grip the boiler at the base.
• Be physically capable.
• Use personal protective equipment as appropriate, e.g.
gloves, safety footwear.
During all manoeuvres and handling actions, every attempt
should be made to ensure the following unless unavoidable and/
or the weight is light.
• Keep back straight.
• Avoid twisting at the waist.
• Avoid upper body/top heavy bending.
• Always grip with the palm of the hand.
• Use designated hand holds.
• Keep load as close to the body as possible.
• Always use assistance if required.
1.4 OPTIONAL EXTRA KITS
Please visit www.keston.co.uk to access the Flue and
Accessories Guide for this boiler.
1.2 OPERATION
With no demand for CH, the boiler res only when DHW is drawn
off, or periodically for a few seconds without any DHW draw-off, in
order to maintain the DHW calorier in a heated condition. This
only occurs if pre-heat knob is in the ‘ON’ period.
When there is a demand for CH, the heating system is supplied at
the selected temperature of between 30
is drawn off. The full output from the boiler is then directed via
the diverter valve to the plate heat exchanger to supply a nominal
DHW draw-off of:
o
30 12.4 l/min at 35
35 14.5 l/min at 35
When using the outside sensor provided please refer to page 33.
The DHW draw off rate specied above is the nominal that the
boiler ow regulator will give. Due to system variations and
seasonal temperature uctuations DHW ow rates/temperature
rise will vary, requiring adjustment at the draw off tap.
C temperature rise.
o
C temperature rise.
o
C and 80oC, until DHW
10
Installation and Servicing
SECTION 1 - GENERAL
0.6m
Zone 0
Recessed
window
Zone 2
Ceiling
3G8913a
2.25m
Zone 1
1.5 SAFETY
Current Gas Safety (installation and use) regulations or rules
in force:
The appliance is suitable only for installation in GB and IE and
should be installed in accordance with the rules in force.
In GB, the installation must be carried out by a Gas Safe
Registered Engineer. It must be carried out in accordance with
the relevant requirements of the:
• Gas Safety (Installation and Use) Regulations
• The appropriate Building Regulations either The Building
Regulations, The Building Regulations (Scotland), Building
Regulations (Northern Ireland).
• The Water Fittings Regulations or Water byelaws in Scotland.
• The Current I.E.E. Wiring Regulations.
Where no specic instructions are given, reference should be
made to the relevant British Standard Code of Practice.
In IE, the installation must be carried out by a Registered Gas
Installer (RGII) and installed in accordance with the current edition
of I.S.813 “Domestic Gas Installations”, the current Building
Regulations and reference should be made to the current ETCI
rules for electrical installation.
Detailed recommendations are contained in the following British
Standard Codes of Practice:
BS. 5440:1 Flues (for gas appliances of rated input not
exceeding 70 kW).
BS. 5440:2 Ventilation (for gas appliances of rated input not
exceeding 70 kW).
BSEN. 12828 Heating Systems in buildings: Design for
water based heating systems.
BSEN 12831 Heating Systems in buildings: Method for
calculation of the design heat load.
BSEN 14336 Heating Systems in buildings: Installation
and commissioning of water based heating
systems.
BS. 5546 Installation of gas hot water supplies for domestic
purposes (2nd Family Gases)
BS. 6798 Installation of gas red hot water boilers of rated
input not exceeding 70 kW.
BS. 6891 Low pressure installation pipes.
Health & Safety Document No. 635.
The Electricity at Work Regulations, 1989.
The manufacturer’s notes must NOT be taken, in any way, as
overriding statutory obligations.
IMPORTANT. These appliances are CE certicated for safety
and performance. It is, therefore, important that no external
control devices, e.g. ue dampers, economisers etc., are
directly connected to these appliances unless covered by
these Installation and Servicing Instructions or as otherwise
recommended by Keston in writing. If in doubt please enquire.
Any direct connection of a control device not approved by Keston
could invalidate the certication and the normal appliance
warranty. It could also infringe the Gas Safety Regulations and
the above regulations.
1.6 SAFE HANDLING OF SUBSTANCES
No asbestos, mercury or CFCs are included in any part of the
boiler or its manufacture.
Installation and Servicing
1.7 LOCATION OF BOILER
The boiler must be installed on a at and vertical internal wall,
capable of adequately supporting the weight of the boiler and any
ancillary equipment.
The boiler may be tted on a combustible wall and insulation
between the wall and the boiler is not necessary, unless required
by the local authority.
For electrical safety reasons there must be no access available
from the back of the boiler.
The boiler must not be tted outside.
Timber Framed Buildings
If the boiler is to be tted in a timber framed building it should
be tted in accordance with the Institute of Gas Engineering
document IGE/UP/7:2006 Edition 2.
Bathroom Installations
This appliance is rated IP20.
The boiler may be installed in any room or internal space,
although particular attention is drawn to the requirements of
the current IEE (BS.7671) Wiring Regulations and the electrical
provisions of the building regulations applicable in Scotland, with
respect to the installation of the boiler in a room or internal space
containing a bath or shower. For IE reference should be made to
the current ETCI rules for electrical installations and I.S. 813.
If the appliance is to be installed in a room containing a bath or
shower then, providing water jets are not going to be used for
cleaning purposes (as in communal baths/showers), the appliance
must be installed beyond Zone 2, as detailed in BS.7671.
Compartment Installations
A compartment used to enclose the boiler should be designed
and constructed specially for this purpose.
An existing cupboard or compartment may be used, provided that
it is modied for the purpose.
Braces for compartments must be easily removable for service access.
In both cases, details of essential features of cupboard /
compartment design, including airing cupboard installation, are to
conform to the following:
• BS 6798 (No cupboard ventilation is required - see ‘Air Supply’
for details).
• The position selected for installation MUST allow adequate
space for servicing in front of the boiler.
• For the minimum clearances required for safety and
subsequent service, see the wall mounting template and
Section 1.13. In addition, sufcient space may be required to
allow lifting access to the wall mounting plate.
• The boiler must be installed on a re resistant surface.
11
SECTION 1 - GENERAL
Pressure drop (mbar )
1.8 GAS SUPPLY
The local gas supplier should be consulted, at the installation
planning stage, in order to establish the availability of an adequate
supply of gas. An existing service pipe must NOT be used without
prior consultation with the local gas supplier.
The boiler MUST be installed on a gas supply with a governed
meter only.
A gas meter can only be connected by the local gas supplier or
by a Gas Safe Registered Engineer. In IE by a Registered Gas
Installer (RGII).
An existing meter should be checked, preferably by the gas
supplier, to ensure that the meter is adequate to deal with the rate
of gas supply required.
It is the responsibility of the Gas Installer to size the gas
installation pipework in accordance with BS6891. Whilst the
principle of the 1:1 gas valve ensures the Keston Combi range
is able to deliver its full output at inlet pressures as low as 14mb,
other gas appliances in the property may not be as tolerant.
When operating pressures are found to be below the minimum
meter outlet of 19mb these should be checked to ensure this is
adequate for correct and safe operation.
Allowing for the acceptable pressure loss of 1mb across the
installation pipework, it can be assumed that a minimum permitted
operating pressure of 18mb will be delivered to the inlet of
the appliance. (Reference BS 6400-1 Clause 6.2 Pressure
Absorption).
The external gas cock could further reduce the operating pressure
when measured at its test point. The pressure drop is relative to
the heat input to the boiler (kW), refer to graph below.
1.10 BOILER CONTROL INTERLOCKS
Central heating systems controls should be installed to ensure
the boiler is switched off when there is no demand for heating, in
compliance with Building Regulations.
Heating systems utilising full thermostatic radiator valve control
of temperature in individual rooms should also be tted with a
room thermostat controlling the temperature in a space served by
radiators not tted with such a valve.
When thermostatic radiator valves are used, the space heating
temperature control over a living / dining area or hallway having
a heating requirement of at least 10% of the minimum boiler heat
output should be achieved using a room thermostat, whilst other
rooms are individually controlled by thermostatic radiator valves.
However, if the system employs thermostatic radiator valves on all
radiators, or two port valves, then a bypass circuit must be tted
with an automatic bypass valve to ensure a ow of water should
all valves be in the closed position.
1.11 ELECTRICAL SUPPLY
WARNING.
This appliance must be earthed.
Wiring external to the appliance MUST be in accordance with
the current I.E.E. (BS.7671) Wiring Regulations and any local
regulations which apply. For IE reference should be made to the
current ETCI rules for electrical installations.
The mains supply to the boiler and system wiring centre shall
be through one common fused double pole isolator and for
new heating systems, and where practical replacement boiler
installations, the isolator shall be situated adjacent to the
appliance.
Gas Cock Pressure Drop
3
2.5
2
1.5
1
0.5
0
0 10 20 30 40 50
Heat Input to Boiler (kW)
IMPORTANT.
Ensure all gas valve connections are gas tight with a gas
soundness check up to the gas control valve.
Installation pipes must be tted in accordance with BS.6891. In IE
refer to IS.813 .
The complete installation MUST be tested for gas tightness and
purged as described in the above code.
1.9 WATER CIRCULATION SYSTEM
IMPORTANT.
A minimum length of 1 metre of copper pipe MUST be tted
to both ow and return connections from the boiler before
connection to any plastic piping.
The central heating system should be in accordance with BS.6798
and, in addition, for smallbore and microbore systems, BS.5449.
WATER TREATMENT - see Section 1.16
1.12 CONDENSATE DRAIN
Refer to Section 2.14
A condensate drain is provided on the boiler. This drain must be
connected to a drainage point on site. All pipework and ttings in
the condensate drainage system MUST be made of plastic - no
other materials may be used.
IMPORTANT.
Any external runs must be in accordance with BS 6798.
The drain outlet on the boiler is sized for standard 21.5mm (3/4”)
overow pipe. It is a universal tting to allow use of different
brands of pipework.
12
Installation and Servicing
SECTION 1 - GENERAL
395
198
89
155
62
30mm
Minimum Top Clearance
100
Air Flue
400
700
2.5
2.5
from case
*
CH FLOW
DATA PLATE
DHW OUTLET
COND. DRAIN
GAS INLET
Centre line
of boiler
DHW INLET
CH RETURN
PRV
43.5 65
28.5 28.5
60.6 75 37.556.4
Underside View - Dimensions to Wall
1.13 BOILER DIMENSIONS, SERVICES & CLEARANCES
The boiler connections are made on the boiler connection tails.
Refer to Section 2.15.
The following minimum clearances must be maintained for
operation and servicing.
Additional space will be required for installation, depending
upon site conditions.
Front clearance
The minimum front clearance when built in to a cupboard is 5mm from
the cupboard door but 450mm overall clearance is still required, with the
cupboard door open, to allow for servicing.
* Bottom clearance
Bottom clearance after installation can be reduced to 5mm.
This must be obtained with an easily removable panel to provide the
100mm clearance required for servicing.
Installation and Servicing
13
SECTION 1 - GENERAL
1.14 SYSTEM REQUIREMENTS - Central Heating
Notes
a. The method of lling, relling, topping up or ushing sealed
primary hot water circuits from the mains via a temporary hose
connection is only allowed if acceptable to the local water
authority.
b. Antifreeze uid, corrosion and scale inhibitor uids suitable for
use with boilers having aluminium heat exchangers may be used
in the central heating system.
General
1. The installation must comply with all relevant national and local
regulations.
2. The installation should be designed to work with flow
temperatures of up to 84
3. All components of the system must be suitable for a working
pressure of 3 bar and a maximum design temperature of 110
o
C. Extra care should be taken in making all connections so
that the risk of leakage is minimised.
The following components are incorporated within the appliance:
a. Circulating pump.
b.
Safety valve, with a non-adjustable preset lift pressure of 3 bar.
c. Pressure gauge, covering a range of 0 to 4 bar.
d. An 8-litre expansion vessel, with an initial charge pressure
of 0.75 bar.
4. ‘Make-up’ Water. Provision must be made for replacing water
loss from the system, either :
a. From a manually lled ‘make-up’ vessel with a readily visible
water level. The vessel should be mounted at least 150mm
above the highest point of the system and be connected
through a non-return valve to the system, tted at least
150mm below the ‘make-up’ vessel on the return side of
the radiators. or
b. Where access to a ‘make-up’ vessel would be difcult, by
pre-pressurisation of the system.
The maximum cold water capacity of the system should
not exceed 143 litres, if not pressurized. However, if
the system is to be pressurized, the efciency of the
expansion vessel will be reduced and a larger vessel
(or smaller system volume) may be necessary. If the
capacity of the vessel is not considered sufcient for this,
or for any other reason, an additional vessel MUST be
installed on the RETURN to the boiler.
Guidance on vessel sizing is given in Table opposite.
5. Filling
The system may be lled by the following method:
Where the mains pressure is excessive a pressure reducing
valve must be used to facilitate lling.
a. Thoroughly ush out the whole system with cold water.
b. Fill and vent the system until the pressure gauge
registers 1bar and examine for leaks. Refer to Section
2.15 for lling detail.
c. Check the operation of the safety valve by raising the
water pressure until the valve lifts. This should occur
within 0.3bar of the preset lift pressure.
d. Release water from the system until the
minimum system design pressure is reached;
1.0 bar if the system is to be pre-pressurised.
o
C.
Safety valve setting bar 3.0
Vessel charge pressure bar 0.5 to 0.75
System pre-charge pressure bar None 1.0
System volume
(litres)
Expansion vessel
volume (litres)
25 1.6 1.8
50 3.1 3.7
75 4.7 5.5
100 6.3 7.4
125 7.8 9.2
150 9.4 11.0
175 10.9 12.9
190 11.9 14.0
200 12.5 14.7
250 15.6 18.4
300 18.8 22.1
For other system volumes
multiply by the factor access 0.063 0.074
Water Flow Rate and Pressure Loss
Max CH Output kW 24.2
Water ow rate l/min 17.3
(gal/min) (3.8)
o
Temperature Differential
C 20
Head available for m.w.g. 3.4
system (ft.w.g.) (11.1)
DOMESTIC HOT WATER
1. The domestic hot water service must be in accordance with
BS 5546 and BS 6700.
2. Refer to Table 1 for minimum and maximum working
pressures. In areas of low mains water pressures the
domestic hot water regulator may be removed from
the DHW ow turbine cartridge. Refer to Section 3.25.
The boiler will require the ow rate to be set to obtain a
temperature rise of 35
o
C at the tap furthest from the boiler.
3. The boiler is suitable for connection to most types of
washing machine and dishwasher appliances.
4. If the shower/mixer valve does not incorporate non-return
valves the following must be followed:
a. The cold inlet to the boiler is tted with an approved
anti-vacuum or syphon non-return valve.
b.
Hot and cold water supplies to the shower are of equal
pressure.
5. Hard Water Areas
Where the water hardness exceeds 200mg/litre, it is
recommended that a proprietary scale reducing device is
tted into the boiler cold supply within the requirements of
the local water company.
IMPORTANT
Provision MUST be made to accommodate the expansion of
DHW contained within the appliance, if a non-return valve is tted
to the DHW inlet, or a water meter with a non-return valve is
installed.
Cold water rising main and pipework in exposed areas need to
be suitably lagged to prevent freezing.
14
Installation and Servicing
1.15 SYSTEM BALANCING
SECTION 1 - GENERAL
The boiler does not normally need a bypass but at least some
radiators on the heating circuit, of load of at least 10% of the
minimum boiler output, must be provided with twin lockshield
valves so that this minimum heating load is always available.
See note regarding thermostatic radiator valves on page 12.
Note. Systems incorporating zone valves which could
completely cut off the ow through the system must also
include a bypass.
1.16 WATER TREATMENT
CENTRAL HEATING
The Keston Combi range boiler has an ALUMINIUM alloy heat
exchanger.
IMPORTANT.
The application of any other treatment to this product may
render the guarantee of Keston Invalid.
Keston recommend Water Treatment in accordance with the
Benchmark Guidance Notes on Water Treatment in Central
Heating Systems.
If water treatment is used Keston recommend only the use of
SCALEMASTER GOLD 100, FERNOX, MBI, ADEY MC1, SENTINEL
X100 or CALMAG CM100 inhibitors and associated water
treatment products, which must be used in accordance with the
manufacturers’ instructions.
Notes.
1. It is most important that the correct concentration of the
water treatment products is maintained in accordance with
the manufacturers’ instructions.
2. If the boiler is installed in an existing system any unsuitable
additives MUST be removed by thorough cleansing. BS
7593:2006 details the steps necessary to clean a domestic
heating system.
3. In hard water areas, treatment to prevent lime scale may be
necessary - however the use of articially softened water is
NOT permitted.
4. Under no circumstances should the boiler be red before
the system has been thoroughly ushed.
BALANCING
1. Set the programmer to ON.
Close the manual or thermostatic valves on all radiators,
leaving the twin lockshield valves (on the radiators referred
to above) in the OPEN position.
Turn up the room thermostat and adjust the lockshield
valve to give an uninterrupted ow through the radiator.
These valves should now be left as set.
2. Open all manual or thermostatic radiator valves and adjust
the lockshield valves on the remaining radiators, to give
around 20
3. Adjust the room thermostat and programmer to NORMAL
settings.
o
C temperature drop at each radiator.
DOMESTIC HOT WATER
In hard water areas where mains water can exceed 200ppm
Total Hardness (as dened by BS 7593 Table 2) a scale
reducing device should be tted into the boiler cold supply
within the requirements of the local water company. The use of
articially softened water, however, is not permitted.
Keston recommend the use of Fernox Quantomat, Sentinel
Combiguard or Calmag CalPhos I scale reducing devices
together with scalemaster in-line scale inhibitor branded Ideal,
which must be used in accordance with the manufacturers’
instructions.
For further information contact:
Fernox Cookson Electronics
Forsyth Road, Sheerwater, Woking, Surrey GU21 5RZ
+44 (0) 870 601 500
Sentinel Performance Solutions
The Heath Business & Technical Park, Runcorn, Cheshire WA7
4QX
Tel: 0800 389 4670
www.sentinel-solutions.net
Scalemaster Water Treatment Products
Emerald Way, Stone, Staffordshire ST15 0SR
Tel: +44 (0) 1785 811636
Calmag Ltd.
Unit 3-6, Crown Works, Bradford Road, Sandbeds, Keighley,
West Yorkshire BD20 5LN
Tel: +44 (0) 1535 210 320
Adey Professional Heating Solutions
Gloucester Road, Cheltenham GL51 8NR
Tel: +44 (0) 1242 546700
Installation and Servicing
15
SECTION 2 - INSTALLATION
2.1 BOILER ASSEMBLY - EXPLODED VIEW
104 CH Return Valve
105 CH Flow Valve
106 DHW Inlet & Outlet
107 Filling Loop Pipe
108 Pump Head
110 Auto Air Vent
111 Divertor Valve Motor
112
Divertor Valve Body & Paddle
113 Pressure Relief Valve
114 Pipe - PRV Outlet
115 Pipe - Flow
116 Pipe - Return
117 Pipe - Expansion Vessel
118 Expansion Vessel
119 Return Group Manifold
120 Flow Group Manifold
121 Plate Heat Exchanger
124 Flow Regulator
127 Flow Sensor/Turbine
131 Water Pressure Switch
135 Pressure Gauge
203 Gas Cock
204 Pipe - Gas Inlet
205 Gas Valve
206 Pipe - Gas Injector
211 Injector Assy
214 Venturi
215 Fan
INSTALLATION
217 Burner
218 Gasket - Burner
219 Sump Clean Out Cover
223 Flue Manifold
224 Flue Manifold Top
227 Clamp Retaining Flue Turret
228 Hose Condensate Internal
229 Siphon Trap
231
Condensate Outlet Connection
302 PCB
304
Control Thermistor (Return)
306 Electrode Ignition
307 Electrode Detection
308 Ignitor Unit
309 Thermistor Flow
313 Ignition Lead
320 Detection Lead
324 Control Box Lid
325 Control Box Front
326 Programmer Insert
401 Heat Engine
503 Wall Mounting Bracket
504 Front Panel
505 Fascia
506 Bracket - Gas Valve
507 Bracket - Expansion Vessel
205
214
206
215
204
211
309
505
504
306
217
218
307
401
313
227
224
503
118
320
507
16
135
326
223
325
324
308
302
219
107
105
506
106
228
229
203
106
304
104
131
116
231
124
108
115
120
127
111
112
110
121
113
117
114
119
Installation and Servicing
SECTION 2 - INSTALLATION
C
A
G
F
B
E
H
Boiler Guarantee
HARDWARE PACK CONTENTS
Gas Valve Pack DHW Pack
Accessory Pack
Flow Valve Pack
Return Valve Pack
Filling Loop
Gas Valve Pack
1. Pipe - Gas Inlet
2. Washer - Gas (blue)
3. Gas Cock
Filling Loop Pack
1. 3/8" Top Hat Washer
2. Valve Filling Loop
3. Pipe Filling Loop
4. Washer
Return Valve Pack
1. Pipe CH Return
2. Washer
3. Valve Return
DHW Pack
1. 1/2" Top Hat Washer (x2)
2. Cap Female
3. Plug Male and Clip
4. Nut G1/2 16 Brass (Flat)
5. Washer 18.5 x 11 x 11.8 (x2)
6. Pipe DHW Outlet
7. Pipe DHW Inlet
8. Valve DHW Inlet
Accessory Pack
1. Screw (x2)
2. Wallplug (x2)
3. Turret Clamp Screw (spare)
Flow Valve Pack
1. Pipe CH Flow
2. Washer CH
3. Valve Flow
1
1
1
3
2
2
2
3
3
1
2
3
2
8
3
3
1 2
1
7
5
6
4
5
4
2.2 UNPACKING
Unpack and check the contents.
PACK 1 CONTENTS
A Boiler
B Hardware Pack Box
C Wall Mounting Plate
D These Installation Instructions
E Wall Mounting Template
(located on internal protective packaging)
F Safety Valve Drain Pipe
G Boiler Guarantee / Registration pack
INSTALLATION
FLUE PACK CONTENTS
A Flue Adaptor
B Air Spigot
C Terminals - 2 off
D Flue Sleeve
E Wall Plate
F Wall Seal
G Outside Sensor
H Screws - 4 off
J Wall Plugs - 4 off
Installation and Servicing
A
G
B
H
C
J
D
E
F
17
SECTION 2 - INSTALLATION
2.3 FLUE SYSTEM
IMPORTANT
When installing a replacement boiler a new ue system is recommended. However re-using the existing
boiler ue installation is acceptable if the installer checks and conrms:
• The ue pipe is the approved Marley/Polypipe/Terrain/Wavin 50mm muPVC solvent weld ue system
• The ue installation is upgraded to the most recent ue standards taking particular care to comply with
ues in voids
• A risk assessment is conducted to conrm the effectiveness of the ue
• The existing ue will last the lifetime of the new appliance
DESIGN
Individual air supply and ue outlet pipes are used as standard.
The material approved for this application which MUST be used are:
- Marley muPVC Solvent Weld System (50mm)
- Polypipe System 2000 muPVC solvent weld (50mm)
- Polypipe Terrain 200 muPVC Solvent Weld System (50mm)
- Wavin OSMA PVC-C Solvent Weld System (50mm)
to BS5255 and/or BSEN1566-11 and BSEN1329, are the only systems approved for this application.
The following pipe and ttings are approved.
Polypipe System 2000 muPVC Solvent Weld System (50mm)
Polypipe Code
MU 301 4m length muPVC wastepipe 5/225
MU 313 50mm x 45 deg muPVC obtuse bend
MU 314 50mm x 92.5 deg muPVC swept bend
MU 310 50mm muPVC straight coupling
MU 316 50mm x 92.5 deg muPVC swept tee
Marley muPVC Solvent Weld System (50mm)
Marley Code
KP 304 50mm x 4m double spigot pipe
KP32 50mm x 45 deg bend
KSC3 50mm straight coupling
KB3 50mm x 88.5 deg bend
KT3 50mm swept tee
Polypipe Terrain Solvent Weld System (50mm)
Polypipe Code
200.2.40 4m length muPVC wastepipe
201.2.135 50mm x 135 deg muPVC bend
1
200.2.91 50mm x 91
210.2 50mm muPVC straight coupling
204.2.135 50mm muPVC swept tee
Wavin OSMA PVC-C Solvent Weld System (50mm)
Wavin Code
2M073 3M lenght waste pipe 50mm
2M163 50mm x 45 deg bend
2M161 50mm x 87.5 deg bend
2M104 50mm double socket
2M190 50mm x 8.75 tee
/4 deg muPVC swept bend
Consideration MUST be given to expansion and contraction of the ue. Refer to Assembly Practice (Section 2.12) in this
installation and Servicing Instructions for further guidance.
FLUE OUTLET
18
18
Installation and Servicing
continued............
SECTION 2 - INSTALLATION
TERMINAL POSITIONS
Flue
Pipe
Elbow
Minimum Separation
140mm
Acceptable
range of air
pipe siting
Terminal
Air Pipe
150mm
FLUE SYSTEM........ CONT’D
TERMINATION OF THE FLUE AND AIR
The ue and air pipes may terminate independently through any
external walls within the same dwelling except on opposing walls,
within the maximum lengths shown in graph below. (Alternatively a
vertical ue pipe termination is acceptable.)
The air pipe must have an elbow and 150mm length of pipe directed
downwards with a termination grill tted.
The air pipe can be situated at the side or beneath the ue pipe to a
minimum dimension of 140mm (see diagram right). It must not be
sited above the ue pipe.
The ue and air pipes must extend by at least 40mm from the wall
surface.
Condensing boilers emit a visible plume of water vapour from the
ue terminal, this is normal. It is the responsibility of the installer to
judiciously select a terminal location that does not cause a nuisance.
If either the ue or air terminal is below a height of 2m from ground
level a terminal guard must be tted.
Note. Any vertical termination MUST have the terminals tted and the
air intake comply with the dimensions above.
MAXIMUM LENGTHS
Due to the resistance presented by extended ue length a slight reduction in maximum boiler output will occur where combined ue
and air lengths in excess of 18.0m and 16.0m (50mm muPVC) are used. In such cases the boiler output will be reduced by 0.6%
and 0.8% per additional metre.
The maximum lengths of both air inlet pipe and ue outlet pipe, when no bends are used, are as detailed in graphs below.
However, each bend used has an equivalent length that must be deducted from the maximum straight length stated in graphs
below. Knuckle bends must not be tted.
A 92.5º swept elbow is equivalent to 1.0m straight length. A 45º bend is equivalent to 0.5m straight length.
It is possible to have variable ue and air lengths as described within the shaded area of graphs below.
Keston Combi C35 - Flue & Air Pipe Length Keston Combi C30 - Flue & Air Pipe Length
SLOPE
‘Horizontal’ ue outlet pipework MUST slope at least 1.5 degrees (26mm per metre run) downwards towards the boiler. Pipework
can be vertical. Only swept elbows can be used.
Air inlet pipework can be truly horizontal or vertical, or sloping in a downward direction towards the boiler but in each case rain,
etc., must be prevented from entering the pipe. There must be no troughs in any of the pipework, whether it be air inlet or
ue outlet.
Installation and Servicing
19
19
FLUE OUTLET
SECTION 2 - INSTALLATION
6m
2m
Bracket at
each 1 metre
1m
4m
1.5m
6m
1.5º back
to boiler
1.5º back
to boiler
Air
Elbows 2 x 1m = 2m
Straights 6+2+0.15 = 8.15m
Total = 10.15m
Overall Flue / Air = 25.65m
Flue
Elbows 3 x 1m = 3m
Straights 4+6+1.5+1 = 12.5m
Total = 15.5m
Calculations
0.15m
Sleeve
2m
2.5m
1.5m
2m
4m
4m
0.15m
3.5m
3.5m
1.5º back
to boiler
Air
Sleeve
1.5º back
to boiler
Bracket every
1 metre
Flue
3 x 90º elbows 3
Straight lengths 2.5
1.5
3.5
4
14.5
Overall Flue / Air = 30.15m
Air
4 x 90º elbows 4
Straight lengths 2
2
3.5
4
0.15
15.65
Calculations
2 4 6 8
10
12
14
16
18
20
22
24
26
28
2
6
10
14
18
22
26
30
Accep t able Op erating Area
Keston Combi 35 - Flue & Air Pipe Length
Flue Pip e Length [m]
Air Pipe Length [m]
15.65
14.5
2 4 6 8 10
12
14
16
18
20
22
24
26
28
30
2
6
10
14
18
22
26
30
34
38
Accep t able Op erating Area
Keston Combi 30 - Flue & Air Pipe Length
Flue Pip e Length [m]
Air Pipe Length [m]
10.15
15.5
2.4 FLUE INSTALLATION EXAMPLE KESTON COMBI C30
Keston Combi C30 - Flue & Air Pipe Length
2.5 FLUE INSTALLATION EXAMPLE KESTON COMBI C35
FLUE OUTLET
20
20
Keston Combi C35 - Flue & Air Pipe Length
Installation and Servicing
SECTION 2 - INSTALLATION
2.6 FLUE TERMINATION POSITION
When Flue & Air Terminals are
Twin Flue Positions
less than 500mm apart
Flue min. spacing Air min. spacing Flue min. spacing Air min. spacing
A Below an opening (1) 300mm 50mm 300mm 50mm
B Above an opening (1) 300mm 50mm 300mm 50mm
C Horizontally to an opening 300mm 50mm 300mm 50mm
D Below gutters,soil pipes or drain pipes 75mm 75mm 75mm 75mm
E Below eaves 200mm 50mm 200mm 50mm
F Below balcony or car port roof 200mm 50mm 200mm 50mm
G From a vertical drain pipe or soil pipe 150mm 50mm 150mm 50mm
H From an internal or external corner or to a boundary
200mm 50mm 200mm 50mm
alongside the terminal (2)
I Above ground,roof or balcony level 300mm 100mm 300mm 100mm
J From a surface or boundary facing the terminal 600mm 100mm 600mm 100mm
K From a terminal facing a terminal 1200mm 1200mm 1200mm 1200mm
L From an opening in the car port into the building 1200mm 100mm 1200mm 100mm
M Vertically from a terminal on the same wall 1500mm 1500mm 1500mm 1500mm
N Horizontally from a terminal on the same wall 300mm 300mm 300mm 300mm
O From the wall on which the terminal is mounted 40mm 40mm 40mm 40mm
P From a vertical structure on the roof NA NA 300mm NA
Q Above intersection with roof NA NA 150mm NA
,(1) In addition, for temperature and structural reasons, the terminal should not be nearer than 150 mm (fanned draught) to an
opening in the building fabric formed for the purpose of accommodating a built-in element such as a window frame
,(2) The reference to external corners does not apply to building protrusions not exceeding 450 mm, such as disused chimneys on
external walls for: fanned draught appliances
When Flue & Air Terminals are
more than 500mm apart
When running flue pipes vertically
they MUST be a minimum of 140mm apart
and termination MUST comply with Section 2.3 an 2.6.
A
A
B
A = 600mm
B = 2000mm
The flue terminal shall not penetrate
the shaded area of the roof
Pitched roof with structure
300mm
min
150mm
min
A
RF9807
If chimney penetrates dotted area such that
A is less than 300mm,
B shall not be less than 300mm.
TERMINAL POSITIONS
Flue
Pipe
Minimum Separation
140mm
Elbow
150mm
Installation and Servicing
Vertical termination must have an
elbow with terminal fitted directed from
roof, 150mm above roof intersection
with air taken from side wall or low level
(min 500mm separation).
Air Terminal
Acceptable
range of air
pipe siting
Air Pipe
Terminal
continued . . . . . . . .
21
21
FLUE OUTLET
SECTION 2 - INSTALLATION
..............FLUE TERMINATION
GENERAL INSTALLATIONS
All parts of the system must be constructed in accordance with BS 5440 Part 1, except where specically mentioned in these
instructions.
All pipe work must be adequately supported.
All joints other than approved push-on or plastic compression connectors must be made and sealed with solvent cement suitable
for muPVC pipes and conforming to BS 6209: 1982.
Consideration must be given to Corgi/Gas Safe bulletin TB200/TB008 regarding ues in voids.
The boiler casing must always be correctly tted to the boiler when leaving the appliance operational.
External wall faces and any internal faces of cavity walls must be good.
AIR SUPPLY
INSTALLATION
The Keston Combi is a room-sealed appliance and therefore does not require purpose provided ventilation to the boiler room for
combustion air.
COMPARTMENT INSTALLATION
Due to the low casing temperatures generated by the boiler, no compartment ventilation is required. However, the cupboard or
compartment must not be used for storage.
2.7 INSTALLING THE BOILER
Installation of the boiler is straightforward but consideration must be given to access to allow ue and air pipes to be pushed
through walls and ceilings. The order in which the components are installed will depend upon particular site conditions, but in
general it will be easiest and most accurate to install the boiler and then build up the ue outlet and air inlet pipes to the terminal this is the sequence described.
2.8 WALL MOUNTING TEMPLATE
The wall mounting template is located on the internal protective packaging.
Note.
The template shows the positions of the xing holes and the position of the air and
ue connections. Care MUST be taken to ensure the correct holes are drilled.
1. Tape template into the selected position. Ensure squareness by hanging a
plumbline as shown.
2. Mark onto the wall the following:
a The wall mounting plate screw positions (choose one from each group).
b The position of the air and ue when exiting straight out of the wall where the
boiler is mounted.
Note. Mark the centre of the hole as well as the circumference.
3. Remove the template from the wall.
22
Installation and Servicing
SECTION 2 - INSTALLATION
esp9496
Example of fixing
3G10030
X
Section
through wall
Note. Check all of the hole
positions before drilling.
Rear flue only
60mm diameter
holes
2.9 PREPARING THE WALL
IMPORTANT.
Ensure that, during the cutting operation, masonry falling outside of the
building does not cause damage or personal injury.
1. Cut the ue and air holes (preferably with 60mm core bore tool)
ensuring the holes are square to the wall.
2. Drill 2 holes with a 7.5mm / 8mm masonry drill and insert the plastic
plugs, provided, for the wall mounting plate.
3. Locate 2 No.14 x 50mm screws in the wall mounting plate (one at
each side, in any of the 3 holes provided at each side) and screw
home.
INSTALLATION
2.10 FITTING THE WALL MOUNTING
PLATE
Screw the wall mounting plate to the wall using 2 wall plugs
(previously tted) with the 2 screws provided.
Choose one of the 2 sets of slots in left and right bank.
Ensuring that at least one of the screws is tted into a top
slot.
2.11 MOUNTING THE BOILER
1. Ensure the plastic plugs are removed from both the CH
and DHW connections before mounting the boiler.
2. Lift the boiler onto the wall mounting plate (refer to the
Introduction section for safe handling advice), locating it
over the two tabs.
Installation and Servicing
23
SECTION 2 - INSTALLATION
2.12 ASSEMBLY PRACTICE
Remove all plastic debris and burrs when installing air intake piping. Plastic llings caused by cutting muPVC pipe must not be
allowed to be drawn into the combustion air blower. Prevent dust entering the air intake when cutting on building sites. Blower
failure which is determined to be caused by plastic lings or other debris will not be covered by guarantee.
INSTALLING FLUE AND AIR PIPES
Important - When installing a replacement boiler, a new ue
system is recommended.
However re-using the existing boiler ue installation is
acceptable if the installer adheres to Section 2.3 Flue System Important, and also checks and conrms the following:
• Remove the ue adaptor and air spigot from the ue pack
supplied with the boiler.
• Remove boiler front panel - Section 3.2.
• Remove air intake blanking plate by unscrewing 4 x M5
screws and put to one side, leaving sponge gasket in
place.
• Fix air spigot to boiler using the 4 M5 screws, see diag.
below. Ensure sponge gasket is in place and not damaged.
• Ensure the condense trap/siphon is lled with water.
• Insert the ue adaptor into the ue manifold on the top of the
boiler and secure using the clamp provided in the packaging
box, see diagram below.
• Measure, cut and check the air and ue pipes to pass to the
exit from the wall(s) or ceiling.
• Always thoroughly deburr all pipes and most important,
remove shavings from within the pipe.
• Using the same methods drill any further holes (always
covering existing pipework), cut and assemble the pipework.
• From outside, complete the two terminations - See Section
2.3 Flue System and make good all holes. (Wall sealing
collars are available to make good hole areas on the wall
face (part number C.08.0.00.07.0).
• Support any pipes whose route could be displaced
either of its own accord or by accident. Any horizontal
run over 1m or vertical runs of any length must always
be supported. Brackets should be placed at intervals
of approximately 1m. Brackets should be loose enough
on the pipe to allow thermal expansion and contraction
movement.
• Flue pipework through walls MUST be sleeved to allow
thermal expansion and contraction movement.
• Check all connections for security and re-seal any joints
using solvent cement where soundness may be in doubt.
Note. It is equally important to seal the air inlet with solvent
cement as the ue outlet pipe joints.
• Assemble, using solvent weld cement, the pipework from
the boiler connections to the exit from the rst wall/ceiling,
(remount the boiler if removed). When pushing pipe through
walls, ensure grit and dust is not allowed to enter the pipe.
Ensure pipes are fully engaged into sockets and solvent
welded with no leaks.
FLUE OUTLET
24
24
Installation and Servicing
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