Keston HEAT 2 45 User guide

When replacing any part on this appliance, use only spare parts that you can be assured conform to the safety and performance
specification 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 specification and maintenance practices visit our website www.keston.co.uk
where you can download the relevant information in PDF format.
August 2020
UIN 220446 A01
INSTALLATION
& SERVICING
HEAT 2
45 55 45P 55P

ERP DATA
MODEL
SYMBOL UNITS 45 55 45P 55P
Condensing Boiler n/a n/a yes yes yes yes
Low Temperature Boiler n/a n/a no no no no
B1 Boiler n/a n/a no no no no
Cogeneration Space Heater n/a n/a no no no no
Equipped with a Supplementary Heater n/a n/a no no no no
Combination Heater n/a n/a no no no no
Nominal Heat Output for Space Heating
Full Load P4kW 45 55 45 55
Part Load P1kW 14.6 18 14.6 18
Auxiliary Electricity Consumption
Full Load elmax kW 0.135 0.128 0.113 0.130
Part Load elmin kW 0.03 0.026 0.026 0.024
Standby PSB kW 0.009 0.009 0.002 0.002
Seasonal Space Heating Energy Efciency
Full Load ƞ4% 88.7 89.5 88.7 89.5
Part Load ƞ1% 97.7 98.5 97.7 98.5
Standby Loss Pstby kW 0.08 0.11 0.073 0.082
Ignition Pign kW 0 0 0 0
Emissions NOxmg/kWh 28.5 35.4 43.1 48.4
Annual Energy Consumption QHE GJ 139 170 137 167
Sound Power Level, Indoors LWA dB 60.6 60.6 64.2 64.2
 
2
Installation & Servicing

KESTON HEAT2 BOILER
Keston Heating
ERP DATA SYMBOL UNITS MODEL
45 45P 55 55P
Condensing boiler Yes
Seasonal Space heating efciency class A
Rated heat output kW 45 45 55 55
Seasonal space heating energy efciency ƞson % 93* 93* 93* 93*
Annual energy consumption QHE GJ 139 137 170 167
Sound power level, indoors LWA dB 60.6 60.6 64.2 64.2
Seasonal Space Heating Energy Efciency 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%
PRODUCT FICHE
 
The energy efciency of the package of products provided for in this document may not correspond to its actual energy efciency once installed in a
building, as the efciency is inuenced by further factors such as heat loss in the products in relation to the building size and its characteristics
Collector Size
(in m2)Tank Volume (in m3)Collector Efciency
(in %)
Tank rating
A* = 0.95
A = 0.91
B = 0.86
C = 0.83
D-G = 0.81
Solar Contribution (from che of solar device)
Seasonal Space Heating Energy Efciency of Package TOTAL: A+B+C=
Seasonal Space Heating Energy Efciency Class of Package
= (‘III ’x + ‘IV ’ x ) x 0.9 x ( / 100 x = %
%
GG F E D C B A A+ A++ A+++
< 30% ≥ 30% ≥ 34% ≥ 36% ≥ 75% ≥ 82% ≥ 90% ≥ 98% ≥ 125% ≥ 150%
A
B
C
3
Installation & Servicing

4
Installation & Servicing

1. GENERAL.........................................................................8
1.1 Introduction........................................................................8
1.2 Optional Extra Kits.............................................................8
1.3 Safety ................................................................................8
1.4 Safe Handling....................................................................9
1.5 Safe Handling of Substances............................................9
1.6 Location of Boiler...............................................................9
1.7 Gas Supply........................................................................9
1.8 Flue Installation .................................................................9
1.9 Water Circulation System..................................................9
1.10 Water Treatment..............................................................10
1.11 Electrical Supply..............................................................11
1.12 Condensate Drain............................................................11
1.13 Boiler Clearances and Connections................................12
1.14 Open Vented System Requirements...............................13
1.15 Sealed System Requirements.........................................13
2. INSTALLATION...............................................................14
2.1 Boiler Assembly - Exploded View....................................14
2.2 Packaging Removal.........................................................15
2.3 Unpacking .......................................................................15
2.4 Wall Mounting Template ..................................................16
2.5 Preparing the wall............................................................16
2.6 Mounting the Boiler..........................................................17
2.7 Ventilation........................................................................17
2.8 Flue Systems...................................................................18
2.9 Flue Termination Position................................................20
2.10 Assembly Practice...........................................................21
2.11 Fitting the Flue Sleeving..................................................22
2.12 Flue Installation Example Keston Heat 55.......................23
2.13 Flue Installation Example Keston Heat 45.......................23
2.14 Boiler Frame and header Kits..........................................24
2.15 condensate drain.............................................................25
2.16 Boiler Water Connections................................................26
2.17 Frost Connection.............................................................27
2.18 Gas Connection...............................................................27
2.19 Fitting the Weather Compensation Kit ............................27
2.20 Stand Alone Boiler - Partial Hydraulics............................28
2.21 Abbreviations...................................................................30
2.22 Electrical Connections.....................................................30
2.23 External Wiring................................................................30
2.24 Installer Connections.......................................................31
2.25 Boiler with External Controls ..........................................32
2.26 Controls Conguration, Commissioning and Testing.......35
2.27 User Interface..................................................................36
2.28 Glossary of Terms............................................................37
2.28.1 Menu function resource denitions..................................37
2.28.2 Pump denitions..............................................................37
2.29 Boiler Guided Conguration Stand Alone Boiler .............38
2.29.1 Initial Settings..................................................................38
2.29.2 Boiler setup options - Pre conguration selection ..........39
2.29.3 Advanced Conguration ..................................................39
2.29.4 Plant Settings ..................................................................40
2.29.5 Boiler Conguration:........................................................43
2.29.6 Heating Circuit Conguration:..........................................45
2.29.7 DHW Conguration..........................................................47
2.29.8 Menu – Conguration – General – Access level..............50
2.29.9 Menu - Conguration.......................................................50
2.30 Initial Lighting...................................................................51
2.31 General Checks...............................................................52
2.32 Handing Over ..................................................................52
2.33 Safety ..............................................................................52
3. SERVICING.....................................................................53
3.1 Servicing Schedule..........................................................53
3.2 Removal of Casing..........................................................54
3.3 Removal of Fan and Gas Valve Assembly ......................55
3.4 Removal of Non-Return Valve.........................................55
3.5 Removal of Burner...........................................................56
3.6 Heat Exchanger Inspection / Cleaning...........................56
3.7 Removal of Condensate Trap..........................................56
3.8 Removal of Sump Cover .................................................57
3.9 Removal of Fan...............................................................57
3.10 Removal of Gas Valve....................................................57
3.11 Removal of Venturi / Air Inlet Damper.............................58
3.12 Removal of Ignition Electrode..........................................58
3.13 Removal of Detection Electrode......................................58
3.14 Removal of Automatic Air Vent........................................59
3.15 removal of Water Pressure Switch ..................................59
3.16 Removal of Flow / Return / Heat exchanger Thermistor .59
3.17 Flue Thermistor Replacement.........................................60
3.18 Removal of Spark Generator...........................................60
3.19 Pump Head replacement.................................................61
3.20 Removal of Main PCB.....................................................62
3.21 Removal of System Manager..........................................62
4. WIRING...........................................................................63
4.1 Internal Wiring Combustion Manager..............................63
4.2 System Manager Wiring Diagram....................................64
4.3 Optional Varican Adapter wiring Diagram........................64
5. FAULT FINDING .............................................................65
5.1 Fault Finding Screens......................................................65
5.2 Fault Finding Menu..........................................................66
5.3 Overheat Lockout............................................................68
5.4 Ignition Lockout ...............................................................68
5.5 False Flame Lockout / Error 20.......................................69
5.6 Low Water Pressure........................................................69
5.7 Flame Loss......................................................................69
5.8 Fan Fault .........................................................................70
5.9 Flow / Return Thermistor, Heat Exchanger or Flue
Thermistor Fault ..............................................................70
5.10 Outside / HEADER / ROOM Sensor Fault (if tted).........70
5.11 Flow/Return Reversed.....................................................71
5.12 Cylinder Thermistor Fault (if tted) ..................................71
5.13 External Interlock Open...................................................71
5.14 No CH but DHW OK........................................................72
5.15 No DHW but CH OK........................................................73
5.16 No Display.......................................................................74
5.17 0-10V Interface................................................................74
6. SPARE PARTS ...............................................................75
7. COMBUSTION AND FLUE INTEGRITY.........................76
7.1 Flowchart for CO Level and Combustion Ratio Check on
Commissioning A Condensing Boiler...............................76
CONTENTS
5
Installation & Servicing

Note.
Gas consumption is calculated using the following caloric values
at 15oC and 1013.25 mbar.
G31 Gross CV - 95.7 MJ/m3
G20 Gross CV - 37.8 MJ/m3
G31 Gross CV - 2567 Btu/ft3
G20 Gross CV - 1014 Btu/ft3
For l/s divide the gross heat input (kW) by the gross C.V. of the
gas (MJ/m3)
For ft/h3 divide the gross heat input (Btu/h) by the gross C.V. of
the gas (Btu/ft3).
For m3/h multiply l/s by 3.6.
* The value is used in the UK Government’s Standard Assessment Procedure (SAP) for energy ratings of dwellings. The test data from which it has
been calculated have been certied by a notied body.
Table 2 General Data
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 certied 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 certication and the normal appliance
warranty. It could also infringe the Gas Safety Regulations and
the above regulations.
Keston Heat2 Model 45 45P 55 55P
Boiler Output
(non-condensing)
Mean 70°C
Max kW 42.6 42.6 52.1 52.1
Min kW 12 12 12 12
Boiler Output
(condensing)
Mean 40°C
Max kW 45 45 55 55
Min kW 12.7 12.7 12.7 12.7
Boiler Input
Max Rate Nett kW 43.2 43.2 52.7 52.7
Gross kW 47.9 47.9 58.5 58.5
Boiler Input
Min Rate Nett kW 12.2 12.2 12.2 12.2
Gross kW 13.5 13.5 13.5 13.5
Gas Rate Max Rate m3/hr 4.56 1.78 5.57 2.18
Flue Gas Flow Rate Max Rate m3/hr 65.8 68.03 80.6 83.71
CO2 (±0.5%) Max Rate % 9.5 10.8 9.7 10.7
Min Rate % 8.7 9.9 8.7 9.9
DB 60.6 60.6 64.2 64.2
NOx Weighted mg/kWh 28.5 43.1 35.4 48.4
Efciency Seasonal % 96 96 96.7 96.7
*SEDBUK 2009 % 89.2 89.2 89.6 89.6
Keston Heat2 Model 45P 45 55 55P
Gas Supply 3P-G31-37mbar 2H – G20 – 20mbar 3P - G31 - 37mbar
Gas Supply Connection G 3/4
Flow Connection G1 1/4
Return Connection G1 1/4
Max Pressure (sealed sys) Bar (psi) 6.0 (87.0)
Maximum Static Head m 61.0
Electricity Supply 230V - 50Hz
Fuse Rating A 4.0
Power Consumption W 180 180 241 241
IP Rating IP20
Nominal ue dia - Concent. Twin 50mm
Condensate Drain 25
Water Content L 5.0
Packaged Weight Kg TBA
Unpackaged Weight Kg TBA
Table 1 Performance Data (Natural Gas & Propane)
6
Installation & Servicing
SECTION 1 - GENERAL

Key to symbols
IE = Ireland
GB = United Kingdom
RO = Romania
PMS = Maximum operating pressure of water
B23 = An appliance intended to be connected to a ue which evacuates the products of combustion to the outside of the room
containing the boiler. The combustion air is drawn directly from the room. The fan is up stream of the combustion
chamber. Note: Air Inlet Kit must be used.
C13 = A room sealed boiler which is connected via its ducts to a horizontally installed terminal that terminates within a common
pressure zone.
C53 = A room sealed boiler which is connected via its separate ducts to two terminals that may terminate in zones of different
pressure.
I2H = An appliance designed for use on 2nd Family gases.
I3P = An appliance designed for use on 3rd family gases.
II2H3P = An appliance designed for use on 2nd and 3rd Family gases.
KESTON HEAT2
45, 55
45P, 55P
Natural Gas & Propane
Destination Countries: GB, IE, RO
CE No. 701341
Boiler size G.C. Appliance No.
(Benchmark No.)
NOTE TO THE INSTALLER: LEAVE THESE INSTRUCTIONS ADJACENT TO THE GAS METER.
45 41-930-50
55 41-930-51
45P 41-930-52
55P 41-930-53
7
Installation & Servicing
SECTION 1 - GENERAL

1. GENERAL
1.1 INTRODUCTION
The boilers are fully automatically controlled, wall mounted,
fanned, super efcient condensing appliances.
The condensing boilers can be installed either on the wall or into
a prefabricated oor mounted frame.
The boilers are suitable for use with a room sealed ue or open
ue application.
Through a sophisticated control system combined with premix
burner arrangement the boilers are capable of high seasonal
efciencies of >96% and low emissions.
These boilers are tted with an integral ue non-return valve.
These boilers are certied to meet the requirements of the EC
Gas Appliance Directive, Boiler Efciency Directive, EMC and
Low Voltage Directive.
Note. These boilers cannot be used on systems that include
gravity circulation.
The boiler are suitable for connection to fully pumped, open
vented or sealed water systems. Adequate arrangements for
completely draining the system by provision of drain cocks MUST
be provided in the installation pipework.
1.2 OPTIONAL EXTRA KITS
SYSTEM
• Frame and Header Kits & accessories
CONTROLS
• Outside temperature sensor
• DHW tank sensor/Flow sensor/Header sensor. Pocket version
• DHW tank sensor/Flow sensor/Header sensor. Strap-on
version
• Room temperature sensor
• OpenTherm room control
• Safety interlock kit
• Cascade, rst boiler
• Cascade, subsequent boiler
• Extension module
• Modulating sequencer kit
• Sequencer, OpenTherm room control
• 6 relay zone expansion kit
• Sequencer and zone expansion pocket sensor, DHW or ow
temperature
• RDG, remote diagnostic gateway
• OpenTherm to Modbus gateway
• OpenTherm to BACnet gateway
• OpenTherm to LONworks gateway
• OpenTherm to KNX gateway
1.3 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 suitably qualied Gas
Safe registered engineer or in IE by a competent person. 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.T. Wiring Regulations.
Where no specic 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 Competent Person and
installed in accordance with the current edition of I.S.813 “Domestic
Gas Installations” or I.S. 820 “Non-Domestic Gas Installations” as
appropriate, the current Building Regulations and reference should
be made to the current ETCI rules for electrical installation
.
The boilers have been tested and certied to;
BSEN 15502-1, BSEN 15502-2, BSEN 15502-2-1, BSEN 60335-1,
BSEN 60335-1, BSEN 60335-2-102, BSEN 55014-1
and BSEN
55014-2 for use with Natural Gas & Propane.
Detailed recommendations are contained in the following Codes
of Practice:
BSEN 60529 IPX4D using test method: Figure 4 - Test
device to verify protection against spraying and
splashing water; second characteristic numerals
3 and 4 (oscillating tube).
BS. 6891 Installation of low pressure gas pipework of up to
28mm (R1) in domestic premises (2nd family gas).
BS. 5440 Inst. and maintenance of ues and ventilation for
gas appliances of rated input not exceeding 70kW
net (1st, 2nd and 3rd family gases).
Part 1 Specication for installation of ues.
Part 2 Specication for installation and maintenance of
ventilation for gas appliances.
BS. 6798 Installation and maintenance of gas red hot water
boilers of rated input not exceeding 70kW net.
BS. 6880 Low temperature hot water heating systems of
output greater than 45kW.
Part 1 Fundamental and design considerations.
Part 2 Selection of equipment.
Part 3 Installation, commissioning and maintenance.
BSEN.12828:2012 Heating Systems in buildings: Design for water
based systems.
BSEN.12831:2017 Heating Systems in buildings: Method for
calculation of the design heat load.
BSEN.13831 Specication for: Expansion vessels using an
internal diaphragm, for sealed hot water heating
systems.
BSEN.14336:2004 Heating Systems in buildings: Installation and
commissioning of water based heating systems.
IGEM/UP/1 Soundness testing and purging of industrial and
commercial gas installation.
IGEM/UP/2 Gas installation pipework, boosters and
compressors on industrial and commercial
premises.
IGEM/UP/10 Installation of gas appliances in industrial and
commercial premises.
8
Installation & Servicing
SECTION 1 - GENERAL

ICOM Water treatment and conditioning of commercial
heating systems guide.
Where reference is made throughout these instructions I.S.813:2002
“Domestic Gas Installations” reference should also be made to
I.S.820:2000 “Non-Domestic Gas Installations” as applicable.
1.4 SAFE HANDLING
This boiler will 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.
1.5 SAFE HANDLING OF SUBSTANCES
No asbestos, mercury or CFCs are included in any part of the
boiler or its manufacture.
1.6 LOCATION OF BOILER
The boiler must be installed on a at and vertical wall capable of
adequately supporting the weight of the boiler and any ancillary
equipment or on a boiler frame supplied in kit form.
The wall must be 90º (±5º) from the perpendicular. This is to allow
safe operation of the integral ue non-return valve.
The boiler must not be tted outside.
1.7 GAS SUPPLY
IMPORTANT
Ensure all gas valve connections are gas tight with a gas
soundness check up to the gas multi-functional control
valve.
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.
A gas meter can only be connected by the local gas supplier or
by a suitably qualied Gas Safe registered engineer or in IE by a
competent person.
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. Aminimum working gas pressure of
17.5mbar MUST be available at the boiler inlet for Natural gas
and 32mbar for Propane.
Do not use pipes of smaller size than the boiler inlet gas connection.
The complete installation MUST be tested for gas soundness and
purged in accordance with the appropriate standards listed on page 8.
1.8 FLUE INSTALLATION
Individual air supply and ue outlet pipes are used. The material
used for the ue outlet and the air intake systems, must be
muPVC (PVC-C) to BS 5255. In addition the ue outlet and air
intake pipework must be marked BSEN 1566-1 and the ttings
must be marked BSEN 1329. Marley muPVC Solvent Weld
System (50mm), Polypipe System 2000 muPVC Solvent Weld
System (50mm), Wavin Osma Solvent Weld System and Polypipe
Terrain 200 muPVC Solvent Weld System are recommended.
DO NOT USE ABS PIPE OR FITTINGS.
IMPORTANT
It is the responsibility of the installer to ensure, in practice, that
products of combustion discharging from the terminal cannot
re-enter the building or any other adjacent building through
ventilators, windows, doors, other sources of natural air inltration,
or forced ventilation / air conditioning.
If this should occur the appliance MUST be turned OFF, labelled
as ‘unsafe’ and corrective action taken.
Where the lowest part of the terminal is tted less than 2m above
a balcony, above ground or above a at roof to which people
have access then the terminal MUST be protected by a purpose
designed guard. The minimum spacing between the balcony and
the terminal should be 75mm, in order to allow a terminal guard to
be tted.
Terminal guards are available from boiler suppliers
Ensure that the guard is tted centrally.
The air inlet/products outlet duct and the terminal of the boiler
MUST NOT be closer than 25mm to combustible material.
Detailed recommendations on the protection of combustible
material are given in BS. 5440-1. In IE refer to I.S.813.
The ue must be installed in accordance with Building
Regulations and the recommendations of BS. 5440-1 for inputs
up to 70kW nett.
1.9 WATER CIRCULATION SYSTEM
The boiler must NOT be used for direct hot water supply. The hot
water storage cylinder MUST be of the indirect type.
Single feed, indirect cylinders are not recommended and MUST
NOT be used on sealed systems.
The appliances are NOT suitable for gravity central heating nor
are they suitable for the provision of gravity domestic hot water.
The hot water cylinder and ancillary pipework, not forming part of
the useful heating surface, should be lagged to prevent heat loss
and any possible freezing - particularly where pipes run through
roof spaces and ventilated underoor spaces.
The boiler must be vented.
Draining taps MUST be located in accessible positions, which
permit the draining of the whole system - including the boiler
and hot water storage vessel. They should be at least 1/2” BSP
nominal size and be in accordance with BS. 2879.
The central heating system should be in accordance with the
relevant standards listed on page 8.
The Keston boilers feature an integral circulating pump which
has sufcient excess head to drive most domestic systems. The
available head is indicated in the chart below. If the system
resistance, at the desired ow rate, is in excess of the available
head from the integral pump an additional system pump will be
required.
9
Installation & Servicing
SECTION 1 - GENERAL

30 40 50 60 70
0
1
2
3
4
5
6
7
8
Available System Capacity
30 deg C differential
25 deg C differential
20 deg C differential
15 deg C differential
Keston Evomax 55 - Hydraulic System Capacity
Water Flow Rate [L/m]
Pressure [m WG]
Keston Heat 2 55 - Hydraulic System Capacity
30 40 50 60 70
0
1
2
3
4
5
6
7
8Available System Capacity
25 deg C differential
20 deg C differential
15 deg C differential
11 deg C differential
Keston Evomax 45 - Hydraulic System Capacity
Water Flow Rate [L/m]
Pressure [m WG]
Keston Heat 2 45 - Hydraulic System Capacity
The schematic below illustrates a recommended approach to
using an additional system pump. The additional system pump
should be sized to overcome the index circuit resistance only as
the boilers integral pump will overcome boiler resistance.
If an additional pump is required the selected pump must comply
with BS 1394.
Boiler
Safety
Valve AAV Additional
System
Pump
Primary Flow
Primary Return
42mm
Header
Installation of air bleed valves at the high spot(s) in the system will
allow for air elimination when lling the system and will allow re-
venting in a day or so after all air has been driven out of solution.
Note.
• With the boiler ring at minimum rate, the temperature
differential should not be greater than 35oC. Lower ow rates
generating higher temperature differentials will lead to lock out
of the boiler.
In installations where all radiators have been provided with
thermostatic radiator valves, it is essential that water circulation
through the boiler is guaranteed. This can be best achieved
by means of a differential pressure valve, which is installed in a
bypass between the ow and return pipes. The bypass should
be tted at least 6m from the boiler, and should use a minimum
size of 28mm pipe. The bypass should be capable of allowing
a minimum ow rate to achieve a temperature differential of no
greater than 35oC at minimum rate.
1.10 WATER TREATMENT
These boilers incorporate an ALUMINIUM heat exchanger.
IMPORTANT. The application of any other treatment to this
product may render the warrnaty of Keston Heating INVALID.
Keston recommend Water Treatment in accordance with
Guidance Notes on Water Treatment in Central Heating Systems.
If water treatment is used Keston recommend only the use of
SCALEMASTER SM-1 PRO, 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.
For further information contact:
Fernox
www.fernox.com
Tel: [phone]
Sentinel Performance Solutions
www.sentinelprotects.com
Tel: [phone]
Scalemaster Water Treatment Products
www.scalemaster.co.uk
Tel: [phone]
Calmag Ltd.
www.calmagltd.com
Tel: [phone]
Adey
www.adey.com
Tel: [phone]
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.
3. In hard water areas, treatment to prevent lime scale may be
necessary - however the use of articially softened water is
NOT permitted.
4. Under no circumstances should the boiler be red before the
system has been thoroughly ushed.
10 Installation & Servicing
SECTION 1 - GENERAL

1.11 ELECTRICAL SUPPLY
Wiring external to the appliance MUST be in accordance with
the current I.E.T. (BS7671) Wiring Regulations and any local
regulations which apply. For Ireland reference should be made to
the current ETCI rules for electrical installations
The point of connection to the mains should be readily accessible
and adjacent to the boiler.
1.12 CONDENSATE DRAIN
Refer to Sections 2.15 & 3.7
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.
Installation must be in accordance with BS 6798.
The drain outlet on the boiler is sized for standard 21.5mm
overow pipe. It is a universal tting to allow use of different
brands of pipework.
11
Installation & Servicing
SECTION 1 - GENERAL

1.13 BOILER CLEARANCES AND CONNECTIONS
The following minimum clearances must be
maintained for operation and servicing.
Front of boiler - 450mm
Sides of boiler - 25mm
Above boiler - dependent upon the ue
system see drawings
Below boiler - 300mm
Clearance between multiple boiler
installations - 25mm
500
59 59
209 299
118118
FLOW &RETURN CONNECTIONS 81
GAS & CONDENSE OUTLETS 68
B
A
850
FLOW RETURN
GAS
CONDENSE
Boiler Dim. A Dim. B
45, 55 360 130
12
Installation & Servicing
SECTION 1 - GENERAL

Feed/expansion
cistern 500mm
minimum
3000mm
minimum
System
flow to
pump
Inverted cold
feed entry
Cold
Feed
Water
level
(cold)
Open vent
System
return
Connections
to boiler
ima5351
3000
minimum
1.14 OPEN VENTED SYSTEM REQUIREMENTS
1.15 SEALED SYSTEM REQUIREMENTS
Detail reference should be made to the appropriate standards
listed on page 8.
The information and guidance given below is not intended
to override any requirements of the above publications or the
requirements of the local authority, gas or water undertakings.
The vertical distance between the pump and feed/expansion
cistern MUST comply with the pump manufacturer’s minimum
requirements, to avoid cavitation. Should these conditions not
apply either lower the pump position or raise the cistern above
the minimum requirement specied by Keston Heating. The
isolation valves should be tted as close to the pump as possible.
The boiler is tted with an automatic air vent, located in the left
top side of the interior. This air vent must never be shut off, as
this could result in dry ring of the boiler and subsequent damage
to the heat exchanger.
CV CV
Resillient
seat control
valves
Supply
pipe
DT
CV = Control Valve
DT = Drain Tap
Air
gap Tundish
Strainer
Type BA backflow
prevention device
(RPZ valve assembly)
primary flow
and return
ima7349
Note. The method of lling, relling, topping up or ushing sealed primary hot water circuit from the mains for a non-domestic
property is shown below.
1. General
a. Detail reference should be made to the appropriate
standards listed on page 8. The information and guidance
given below is not intended to override any requirements of
these publications or the requirements of the local authority,
gas or water undertakings.
b. The installation should be capable of working with ow
temperatures of up to 90oC and a temperature differential of
up to 35oC at minimum rate only.
c. All components of the system, including the heat exchanger
of the indirect cylinder, must be suitable for a working
pressure of 6 bar (87lbf/in2) and temperature of 110oC. Care
should be taken in making all connections so that the risk of
leakage is minimised.
d. The boiler is tted with an automatic air vent, located in
the left top side of the interior. This air vent must never be
shut off, as this could result in dry ring of the boiler and
subsequent damage to the heat exchanger.
e. Suitable isolation valves and drain points
must be provided by the installer.
2. Safety Valve
A spring loaded safety valve complying with
the relevant requirements of BS. 6759 Pt. 1
must be tted in the ow pipe as close to the
boiler as possible and with no intervening
valve or restriction. The valve should have the
following features:
a. A non-adjustable preset lift pressure not
exceeding 6 bar (87lbf/in2).
b. A manual testing device.
c. Provision for connection of a discharge
pipe. The valve or discharge pipe should
be positioned so that the discharge of
water or steam is visible, but will not cause
hazard to user or plant.
3. Pressure Gauge
A pressure gauge covering at least the range 0-6 bar must be
tted to the system. The gauge should be easily seen from the
lling point and should preferably be connected at the same
point as the expansion vessel.
IMPORTANT NOTE: If the boilers are installed on to an Ideal
frame & header kit and operated in excess of 3 bar then all
safety relief valves will require upgrading. The boiler has a
maximum operating pressure of 6 bar.
4. Expansion Vessel
Expansion vessels used must comply with BS. EN 13831.
Connection to the system must not incorporate an isolating
valve.
13
Installation & Servicing
SECTION 1 - GENERAL

2. INSTALLATION
2.1 BOILER ASSEMBLY - Exploded View
105 Auto Air Vent
201 Gas pipe
202 Flue manifold (lower)
203 Flue manifold (upper)
208 Burner Fixings Kit
230 Fan
231 Gas Valve Kit
232 Venturi Kit
301 Thermistor Kit
302 Lead Ignition Kit
304 Ignitor Unit
305 Electrode Detection Kit
306 Ignition Electrode Kit
308 Fascia Plastic
309 System Manager Board
310 Primary PCB
325 Bulkhead
501 Jacket Assembly Kit
502 Door Assembly Kit
510 Pump
511 Non-return Valve Assembly
512 Air Inlet Damper
613 Air Inlet
700 Flue Adapter
KEY
309 310
501
308
502
325
105
Data Plate
202
203
700
613
301
512
232
231
230
208
301
306
302
304
301
201
510
14
Installation & Servicing
SECTION 2 - INSTALLATION
INSTALLATION

2.2 PACKAGING REMOVAL
2.3 UNPACKING
The boiler is supplied fully assembled in one pack.
When unpacking the boiler check the contents against the items below.
Do not dispose of the packaging until all contents are accounted for, as some parts are held within the cardboard packing pieces.
ACCESSORY BOX
1. The boiler should be laying on its back with
the straps removed.
2. Carefully read the installation instructions
before proceeding.
3. Remove the outer packing sleeve.
4. Remove the protective cardboard wall
mounting template from the front of the
boiler.
5. Remove the packing piece from the top of
the boiler.
6. Check the contents against the list in
Section 2.3 ‘Unpacking’. Note: some items
are contained within the top packing piece.
7. The boiler may now be stood on its base,
with the cardboard bottom packing piece
still in place to protect the connections.
Due care should be taken when standing
up the boilers, with respect to their
weights, see Table 2 on page 6.
x6
x6
x2
x1 x1
x1
x1
x1
x1
x1
x1 x1
x1
Boiler
Connector Kit
Ball Valve
Terminals
M1 Tee
Wall plate
Brass Union Drain Cock Wood Screws Wall Plugs
Weather Compensation Pressure Relief Valve
Wall Seal Flue Sleeve
Wall Mounting Bracket
Wall Mounting Template Installation Guide
User Guide
Log Book
Warranty
Grommet
Hex Head Coach Screws
Wall Plugs
Condensate Trap
Gas Cock
7
3
4
5
x2
x1 x1 x1
x2
x1 x1 x1 x1 x4 x4x2
15
Installation & Servicing
SECTION 2 - INSTALLATION
INSTALLATION

2.4 WALL MOUNTING TEMPLATE
2.5 PREPARING THE WALL
Note. The template shows the positions for the
top xing holes. Care must be taken to ensure
the correct holes are drilled.
1. Tape template into the selected position.
2. Ensure squareness by hanging a plumbline.
3. Mark on to the wall:
a. The top 4 wall mounting plate screw
positions.
b. The 2 boiler lower xing positions using
diagram below
c. The position of the ue duct. Mark
the centre of the hole as well as the
circumference.
4. Remove the template from the wall.
IMPORTANT. The wall must be vertical 90º (±5º)
from the perpendicular to allow safe operation of
the integral ue non-return valve.
Ensure that, during the cutting operation, masonry
falling outside of the building does not cause
damage or personal injury.
1. Drill 4 boiler top xing holes with a 12mm
masonry drill and insert the plastic plugs
provided, for the wall mounting plate.
2. Drill the 2 boiler lower xing holes with a 12mm
masonry drill, insert the plastic plugs provided .
3. Fix the wall bracket into place with 4 M10x70
hex head coach screws provided.
Note: Horizontal ue runs must be
inclined at 1.5-3o to the horizontal to allow
condensate to drain back to the boiler.
BOILER LOWER FIXING POSITIONS
mm332
Ø12mm
850mm to top of boiler
mm17
X
Y
120 245 365 490
Vertical Offset From X mm
Distance from flue centre line (Y) to outside wall surface.
For lengths greater than 8m, increase offset (X) by 60mm
for every additional 1m.
Does not apply to air intake.
8m
6m
4m
2m
16
Installation & Servicing
SECTION 2 - INSTALLATION
INSTALLATION

2.6 MOUNTING THE BOILER
2.7 VENTILATION
• Due care should be taken when lifting the
boilers, with respect to their weights, see
Table 2 on Page 6. Also refer to Section 1.4
Safe Handling.
1. Lift the boiler onto the wall mounting plate as
shown. Note: It is not necessary to hold the
boiler at an angle to engage the wall mounting
plate.
2. Using the remaining coach screws, secure
the bottom of the boiler to the wall through the
attached brackets.
IMPORTANT NOTE It is essential that these bolts
be tted prior to making up the ow and return
connections to the boiler to prevent the boiler
becoming detached .


Keston Heat 45/55 (multiple boiler applications)
Detail reference should be made to BS. 6644 for inputs
between 70kW and 1.8MW (net). In IE refer to the current
edition of I.S.820. The following notes are for general
guidance only:
If ventilation is to be provided by means of permanent
high and low vents communicating direct with outside air,
then reference can be made to the sizes below. For other
ventilation options refer to BS. 6644. In IE refer to the
current edition of I.S.820.
Keston ventilation requirements when installed in a compartment up to 70kW (BS5440)
To a room or internal space To outside Air
Model 45 & 45P 55 & 55P 45 & 45P 55 & 55P
Min Free Area (cm2) 432 527 216 263
If installing in a room or internal space then no purpose provided ventilation is required. When installing in a compartment,
the table below details the ventilation requirements in line with BS5440.
17
Installation & Servicing
SECTION 2 - INSTALLATION
INSTALLATION

2.8 FLUE SYSTEMS
Fig.1
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 conrms:
• 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 conrm 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
200.2.91 50mm x 91 1/4 deg muPVC swept bend
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
Consideration MUST be given to expansion and contraction of the ue. Refer to Assembly Practice (Section 2.10) in this
installation and Servicing Instructions for further guidance.
Both the 50mm ue outlet terminal and the 50mm air inlet terminal are
supplied with the ue pack and are illustrated in Fig. 1 and must be
used in ALL installations. (Both terminals are identical).
continued . . . . .
18
Installation & Servicing
SECTION 2 - INSTALLATION
FLUE OUTLET

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 Fig 3 & 4. (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
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 16.0m (50mm muPVC) are used. In such cases the boiler output will be reduced by 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 gs 3 & 4.
However, each bend used has an equivalent length that must be deducted from the maximum straight length stated in gs 3 & 4.
Knuckle bends must not be tted.
A 92.5º swept elbow is equivalent to 1.0m straight length. A45º 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 Figs 3 & 4.
2 4 6 8 10 12 14 16 18 20 22
2
6
10
14
18
22
26
30
34
38
42
Acceptable Operating Area
Keston Heat 2 - 45 &45P - Flue & Air Pipe Length
Flue Pipe Length [m]
Air Pipe Length [m]
2 4 6 8 10 12 14 16 18 20
2
6
10
14
18
22
26
30
34
38
42
Acceptable operating area
Keston Heat 2 - 55 & 55P - Flue & Air Pipe Length
Flue Pipe Length [m]
Air Pipe Length [m]
SLOPE
‘Horizontal’ ue outlet pipework MUST slope at least 3.5 degrees (60mm 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.
Fig.2
Fig.3 Fig.4
19
Installation & Servicing
SECTION 2 - INSTALLATION
FLUE OUTLET

Twin Flue Positions
When Flue & Air Terminals are
less than 500mm apart
When Flue & Air Terminals are
more 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
CHorizontally 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
alongside the terminal (2) 200mm 50mm 200mm 50mm
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
NHorizontally 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
TERMINAL POSITIONS
Flue
Pipe Elbow
Minimum Separation
140mm
Acceptable
range of air
pipe siting
Terminal
Air Pipe
150mm
AA
B
A
A = 600mm
B = 2000mm
The flue terminal shall not penetrate
the shaded area of the roof
If chimney penetrates dotted area such that
A is less than 300mm,
B shall not be less than 300mm.
When running flue pipes vertically
they MUST be a minimum of 140mm apart
and termination MUST comply with Sections 2.8
150mm
min
300mm
min
Pitched roof with structure
Air Terminal
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). Note. Recomend to fit deflector,
preventing rain ingress
2.9 FLUE TERMINATION POSITION
GENERAL INSTALLATIONS
All parts of the system must be
constructed in accordance with BS
5440 Part 1, except where specically
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.
Consideration must be given to 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
The Keston Heat 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.
20
Installation & Servicing
SECTION 2 - INSTALLATION
FLUE OUTLET