Keston Combi 30, Combi 35 Installation And Servicing Instructions
Installation and Servicing Instructions
FAN POWERED HIGH EFFICIENCY
MODULATING DOMESTIC CONDENSING
GAS COMBINATION BOILER
CE/PI No. 86-CL-38
Combi 30 - GC No. 47-930-04
Combi 35 - GC No. 47-930-05
Combi 30 & 35
These instructions must be left either with the
user or next to the site gas meter.
Keston Heating
PO Box 103, National Avenue, Kingston Upon Hull, HU5 4JN
Tel. +44 (0) 1482 443005 Fax. +44 (0) 1482 467133
email : info@keston.co.uk web : www.keston.co.uk
COMPLIANT WITH BUILDING REGULATION PART L1 & L2
SEDBUK A RATED
2
Keston Combi -
Installation and Servicing
3
Keston Combi - Installation and Servicing
Relevant Installation changes implemented in this book from Mod Level ..................................A01 (Nov 12)
DOCUMENT AMENDMENTS
Keston reserve the right to vary specication without notice
FOR ANY TECHNICAL QUERIES PLESE RING THE KESTON
INSTALLER/TECHNICAL HELPLINE : 01482 443005
NOTE. BOILER RESET PROCEDURE To reset boiler, turn mode knob to reset position and immediately turn knob back to required setting.
The boiler will repeat the ignition sequence if a heat demand is present.
NOTES FOR THE INSTALLER
4
Keston Combi -
Installation and Servicing
general
Table 1 - General Data
Note. Gas consumption is calculated using a
caloric value of 38.7 MJ/m
3
(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 ft
3
/h - divide the gross heat input (Btu/h)
by the gross C.V. of the gas (Btu/ft3)
c. For m
3
/h - multiply l/s by 3.6.
Key to symbols
PMS = Maximum operating pressure of water
C
13 C53
= A room sealed appliance designed for connection via ducts to
a horizontal terminal, which admits fresh air to the burner and
discharges the products of combustion to the outside. The fan is
up stream of the combustion chamber.
I
2H
= An appliance designed for use on 2nd Family gas, Group H only.
* 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.
*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
Keston Combi 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)
Average Flue Temp-Mass Flow Rate (DHW) 68
o
C - 13g/s 73ºC - 15g/s
Maximum Working Pressure (Sealed Systems) bar (lb/in
2
) 2.5 (36.3)
Maximum Domestic Hot Water Inlet Pressure bar (lb/in
2
) 10.0 (145)
Minimum Domestic Hot Water Inlet Pressure* bar (lb/in
2
) 1.3 (18.9) 1.3 (18.9)**
Electrical Supply 230 V ~ 50 Hz.
Power Consumption W 152 177
Fuse Rating External : 3A Internal : T4H HRC L250 V
Water content CH litre (gal) 1.2 (0.26)
DHW litre (gal) 0.5 (0.11)
Packaged Weight kg (lb) 37.8 (83.3) 38 (83.8)
Maximum Installation Weight kg (lb) 32.8 (72.3) 33 (72.8)
Boiler Casing Size Height mm (in) 700 (27.5)
Width mm (in) 395 (15.5)
Depth mm (in) 278 (11)
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
(Btu/h) (82,900) (20,700) (24,100)
Gross CV kW 27.0 6.7 7.9
(Btu/h) (92,000) (23,000) (26,900)
Gas Consumption m
3
/h 2.512 0.623 0.734
(ft
3
/h) (89) (22) (25.9)
Boiler Output :
Non Condensing kW 24.2 6.1 7.1
70
o
C Mean Water temp. (Btu/h) (82,600) (20,700) (24,100)
Condensing kW 25.6 6.4 7.5
40
o
C Mean Water temp. (Btu/h) (87,400) (21,800) (25,500)
Seasonal efciency* SEDBUK 2005
SEDBUK 2009
91.1%
89%
91%
88.9%
NOx Classication CLASS 5
Maximum DHW Input : 30 35
Nett CV kW 30.4 35.4
(Btu/h) (103,600) (120,900)
Gross CV kW 33.7 39.3
(Btu/h) (115,000) (134,200)
Gas Consumption m
3
/h 3.135 3.658
(ft
3
/h) (111 ) (129)
Maximum kW 30.3 35.3
DHW Output (Btu/h) (103,300) (120,500)
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
(gpm) (3.2) (3.7)
5
Keston Combi - Installation and Servicing
general
Boiler size G.C. Appliance No. PI No.
(Benchmark No.)
30 47-930-04 86 CL 38
35 47-930-05 86 CL 38
CONTENTS
Benchmark Commissioning Checklist ..................... 66
Boiler Clearances ......................................................... 9
Boiler Exploded Diagram ........................................... 12
Condensate Drain .......................................... 8,22,23,39
Electrical Connections ............................................... 25
Electrical Supply ........................................................... 8
Fault Finding .......................................................... 57-63
Flue System ........................................................... 14-17
Gas Safety Regulations ............................................... 7
Gas Supply .................................................................... 8
Installation .............................................................. 12-36
Pump ........................................................................... 50
Safe Handling ................................................................ 6
Servicing ................................................................ 37-56
Short List of Parts ...................................................... 64
Thermostatic Radiator Valves ..................................... 8
Water and Systems .......................................... 8, 10-11
Water Connections ..................................................... 24
Water Treatment .........................................................11
Wiring Diagram ........................................................... 30
Natural Gas only
Boiler Page
Make and model ......................................................... 5
Appliance serial no. on data badge .......... Front Cover
SEDBUK No. % .......................................................... 4
Controls
Time and temperature control to heating ................. 26
Time and temperature control to hot water ............. 26
Heating zone valves ................................................ n/a
TRV’s.......................................................................... 8
Auto bypass ............................................................... 8
Boiler interlock ............................................................ 8
For .................................................................... all boilers
Flushing to BS.7593 ................................................. 11
Inhibitor .................................................................... 11
Central heating mode
Heat input ...................................................to be calculated
For assistance see Technical Helpline on the back page
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 ........................................................... 11
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 ..................................................... 22
For all boilers: complete, sign & hand over to customer
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
NOTE TO THE INSTALLER:
COMPLETE
THE BENCHMARK COMMISSIONING
CHECKLIST AND LEAVE THESE
INSTRUCTIONS WITH APPLIANCE
KESTON Combi 30 & 35
6
Keston Combi -
Installation and Servicing
general
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 (20,700 to 82,600 Btu/h)
35 7.1 to 24.2kW (24,100 to 82,600 Btu/h)
Instantaneous domestic hot water (DHW) output is also fully
modulating with a maximum of :
30 30.3kW (103,300 Btu/h)
35 35.3kW (120,500 Btu/h)
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.
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.
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 45
o
C and 83oC, until DHW
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:
30 12.4 l/min at 35
o
C temperature rise.
35 14.5 l/min at 35
o
C temperature rise.
When using the outside sensor provided please refer to page 27.
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.
At low DHW draw-off rate the maximum temperature is limited to
64
o
C by the modulating gas control.
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.
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.
OPTIONAL EXTRA KITS
• Electronic Timer (7 day) kit
• Electronic Programmable Room Thermostat kit
• Stand Off kit
• AirTerminalFinishingKit
• FlueSleeveKit
7
Keston Combi - Installation and Servicing
general
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. 12828:2003 Heating Systems in buildings: Design for
water based heating systems.
BSEN 12831:2003 Heating Systems in buildings: Method for
calculation of the design heat load.
BSEN 14336:2004 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.
SAFE HANDLING OF SUBSTANCES
No asbestos, mercury or CFCs are included in any part of the
boiler or its manufacture.
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. 813:2002.
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.
0.6m
Zone 0
Recessed
window
Zone 2
Ceiling
3G8913a
2.25m
Zone 1
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.
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
Frame 1. 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.
8
Keston Combi -
Installation and Servicing
general
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 BS6891:2005. 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.
IMPORTANT.
Installation pipes must be tted in accordance with BS.6891. In IE
refer to IS.813:2002.
The complete installation MUST be tested for gas tightness and
purged as described in the above code.
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 Frame 5
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.
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.
CONDENSATE DRAIN
Refer to Frames 20 & 21
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.
9
Keston Combi - Installation and Servicing
general
1
BOILER DIMENSIONS, SERVICES & CLEARANCES
all dimensions in mm
The boiler connections are made on the boiler connection tails.
Refer to Frame 22.
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 enable
the consumer to view the system pressure gauge, and to provide
the 100mm clearance required for servicing.
395
198
89
155
62
30mm
Minimum Top Clearance
100395
400
700
FlueAir
2.5
2.5
from case
*
43 65 57 38
Gas Inlet
39 65
10
Keston Combi -
Installation and Servicing
general
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 86
o
C.
3. All components of the system must be suitable for a working
pressure of 3 bar and 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 above.
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.
2
SYSTEM REQUIREMENTS - Central Heating
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 Frame
22 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.
continued . . . . . .
Water Flow Rate and Pressure Loss
Max CH Output kW 24.2
(Btu/h) (82,600)
Water ow rate l/min 17.3
(gal/min) (3.8)
Temperature Differential
o
C 20
(
o
F) (36)
Head available for m.w.g. 3.4
system (ft.w.g.) (11.1)
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
11
Keston Combi - Installation and Servicing
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 8.
Note. Systems incorporating zone valves which could
completely cut off the ow through the system must also
include a bypass.
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
o
C temperature drop at
each radiator.
3. Adjust the room thermostat and programmer to
NORMAL settings.
4
SYSTEM BALANCING
3
SYSTEM REQUIREMENTS cont’d
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 Frame 70. 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. When connecting to suitable showers, ensure that:
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.
5
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 AND F1 or SENTINEL X100
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.
DOMESTIC HOT WATER
In hard water areas where mains water can exceed 200ppm
Total Hardness (as dened by BS 7593:2006 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
12
INSTALLATION
Keston Combi - Installation and Servicing
6
BOILER ASSEMBLY - Exploded View
227
224
503
313
504
505
512
215
217
309
306
308
211
214
206
205
204
223
332
326
325
302
*
104
110
114
113
136
121
118
507
131
128
127
120
119
117
106
203
106
107
135
105
111
231
112
228
229
303
304
116
115
219
301
401
218
307
324
108
314
506
104 CH Return Valve
105 CH Flow Valve
106 DHW Inlet & Outlet
107 Filling Loop
108 Pump Head
110 Air Vent Pump
111 Diverter Valve Head
112 Diverter Valve Cartdrige
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
127 Flow Sensor Hall Effect
128 Flow Turbine Cartridge
131 Water Pressure Transducer
135 Pressure Gauge
136 Safety Valve Drain Pipe
203 Gas Cock
204 Pipe - Gas Inlet
205 Gas Valve
206 Pipe - Gas Injector
211 Injector Assembly
214 Venturi
215 Fan
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
301
Ctrs Box Fixings Hinge & Spring
302 Primary PCB*
303 CUI Board
304 Control Thermistor (Return)
306 Electrode Ignition
307 Electrode Detection
308 Igniter Unit
309 Thermistor No Flow
313 Ignition Lead
314 Control Box Lens
324 Controls Box Lid
325 Control Box Front
326 Programmer Insert
332 Flue Thermostat
401 Heat Engine
503 Wall Mounting Bracket
504 Front Panel
505 Fascia
506 Bracket - Gas Valve
507
Bracket - Exp. Vessel
136 Safety Valve Drain Pipe
512 Drop Down Door
332 Flue Thermostat
* Note that production boiler PCBs are
factory pre-set to operate for boiler range
and output. When ordering Primary PCB
as a spare, an additional Boiler Chip Card
(BCC) MUST also be purchased for your
specic boiler range and output.
Check boiler serial letter code on data
plate to obtain correct BCC.
INSTALLATION
13
INSTALLATION
Keston Combi - Installation and Servicing
7
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 Turret Clamp
G Safety Valve Drain Pipe
H Boiler Guarantee / Registration pack
continued . . . . .
C
A
D F
G
B
E
H
Boiler Guarantee
HARDWARE PACK CONTENTS
Gas Valve Pack
1. Pipe - Gas Inlet
2. Washer - Gas (blue)
3. Gas Cock
Filling Loop Pack
1. 3/8" Fibre washer (x4)
2. Valve (double check valve) fitting
3. Valve - Filling Loop
4. Plastic Chain (x2)
5. Filling Loop
6. 3/8" Blanking Rubber Washer (x2)
Return Valve Pack
1. Pipe CH Return
2. Washer CH
3. Valve Return
DHW Pack
1. Pipe DHW Outlet
2. Valve - Return DHW
3. Washer DHW (x2)
4. Pipe DHW Inlet
5. Nut 1/2"
Accessory Pack
1. Screw (x2)
2. Wallplug (x2)
3. Turret Clamp Screw (x1)
Flow Valve Pack
1. Pipe CH Flow
2. Washer CH
3. Valve Flow (with gauge)
Gas Valve Pack DHW Pack
Accessory Pack
Flow Valve Pack
Return Valve Pack
Filling Loop
3
1
1
1
1
1
5
2
3
3
3
1
2
3
4
6
5
4
2
2
2
2
3
3
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
B
A
G
H
J
F
E
D
C
B
A
G
H
J
F
E
D
C
Flue Pack Contents
INSTALLATION
14
INSTALLATION
Keston Combi - Installation and Servicing
FLUE OUTLET
8
FLUE SYSTEM
IMPORTANT
When installing a replacement boiler a new ue system must be used. DO NOT re-use the existing boiler
ue installation.
DESIGN
Individual air supply and ue outlet pipes are used as standard.
The material approved for this application is which MUST be used is:
Marley muPVC Solvent Weld System (50mm) and Polypipe System 2000 muPVC solvent weld
(50mm), to BS5255 and/or BSEN1566-11 and BSEN1329, are the only systems approved for this
application.
Thefollowingpipeandttingsareapproved.
Polypipe System 2000 muPVC solvent Weld System (50mm)
Poly Pipe 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 straigh coupling
MU 316 50mm x 92.5 deg muPVC swept pipe
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
Consideration MUST be given to expansion and contraction of the ue. Refer to Assembly Practice Frame in this installation and
Servicing Instructions for further guidance.
continued............
15
INSTALLATION
Keston Combi - Installation and Servicing
FLUE OUTLET
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. Theremustbenotroughsinanyofthepipework,whetheritbeairinletorue
outlet.
9
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.
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 below). 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 boiler 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.
TERMINAL POSITIONS
Flue
Pipe
Elbow
Minimum Separation
140mm
Acceptable
range of air
pipe siting
Terminal
Air Pipe
150mm
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.
16
INSTALLATION
Keston Combi - Installation and Servicing
FLUE OUTLET
10
FLUE INSTALLATION EXAMPLE KESTON COMBI 30
11
FLUE INSTALLATION EXAMPLE KESTON COMBI 35
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 table Op erat ing 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 table Op erat ing Area
Keston Combi 30 - Flue & Air Pipe Length
Flue Pip e Length [m]
Air Pipe Length [m]
10.15
15.5
17
INSTALLATION
Keston Combi - Installation and Servicing
FLUE OUTLET
12
FLUE TERMINATION POSITION
Twin Flue Positions
Below an opening (1)
Above an opening (1)
Horizontally to an opening (1)
Below gutters, soil pipes or drain pipes
Below eves
Below balcony or car port roof
From a vertical drain pipe or soil pipe
From an internal or external corner or to a boundary alongside the terminal
Above ground, roof or balcony level
From a surface or a boundary facing the terminal
From a terminal facing the terminal
From an opening in the car port into the building
Vertically from a terminal on the same wall
Horizontally from a terminal on the same wall
300 mm
300 mm
300 mm
75 mm
200 mm
200 mm
150 mm
300 mm
300 mm
600 mm
1200 mm
1200 mm
1500 mm
300 mm
50 mm
50 mm
50 mm
75 mm
50 mm
50 mm
50 mm
50 mm
100 mm
100 mm
1200 mm
100 mm
1500 mm
300 mm
2"
2"
2"
3"
2"
2"
2"
2"
4"
4"
48"
4"
60"
12"
12"
12"
12"
3"
8"
8"
6"
12"
12"
24"
48"
48"
60"
12"
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
L.
M.
N.
Flue Minimum Spacing Air Minimum Spacing
(1) An opening here means an openable element, such as a openable window, or a fixed opening such as an air vent. However, in addition, the outlet should not
be nearer than 150mm (fanned draught) to an opening into the building fabric formed for the purpose of accommodating
a built in element, such as a window frame.
The dimensions given in the table above may need to be increased to avoid wall staining and nuisance depending on site conditions.
boundary
boundary
J
H
L
F
I
G
I
A
B
C
D, E
H
H
K
M
N
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.
Rubber collars are available for ue and air terminals to nish the external wall face around the terminals (Part No C.08.00.07.0).
AIR SUPPLY
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.
18
INSTALLATION
Keston Combi - Installation and Servicing
13 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.
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.
14
WALL MOUNTING TEMPLATE
15
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.
3G10030
X
Section
through wall
Note. Check all of the hole
positions before drilling.
Rear flue only
60mm diameter
holes
INSTALLATION
19
INSTALLATION
Keston Combi - Installation and Servicing
esp9496
Example of fixing
17
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.
16
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.
INSTALLATION
20
INSTALLATION
Keston Combi - Installation and Servicing
FLUE OUTLET
18 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 the boiler on an existing system a
new ue and air intake system MUST also be installed. You
MUST NOT re-use existing ue or air pipework components.
• Remove the ue adaptor and air spigot from the ue pack
supplied with the boiler.
• Remove boiler front panel - Frame 39.
• 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.
• 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.
• 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.
• Using the same methods drill any further holes (always
covering existing pipework), cut and assemble the
pipework.
• From outside, complete the two terminations - See Frame
8 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.
21
INSTALLATION
Keston Combi - Installation and Servicing
FLUE OUTLET
19
FITTING THE FLUE SLEEVE
Flue Sleeve
Flue Pipe
Flue
Terminal
Flexible
Wall
Seal
Wall
Plate
Flue Sleeve Flange
1. Cut hole in wall.
2. Measure wall Thickness
3. Cut sleeve length to match wall thickness & remove burrs.
4. Grout sleeve into wall with ange on external face.
5. Slide ue pipe into sleeve, checking it is free to slide.
6. Slide Flexible wall seal over ue pipe and push centre ring up to sleeve ange when cold.
7. Locate wall plate over exible wall seal and clamp in place using the raw plug pack.
8. Afx ue terminal
9. During boiler test check that the ue end is free to expand and contract with exible wall seal.
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