Keston Combi 30kw, Combi 35kw User Manual

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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

Keston Combi -

Installation and Servicing

NOTES FOR THE INSTALLER

FOR ANY TECHNICAL QUERIES PLEASE 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.

DOCUMENT AMENDMENTS

Relevant Installation changes implemented in this book from Mod Level ..... A02 (Oct 12) and A03 (Feb 14)

Page 11

Water Treatment - Addition of Adey Professional Heating Solutions

Page 31

Item “3” added to Electrical Installation Statement added ref to commissioning process of combustion

Page 67

New Page Added - Benchmark Commissiong & Servicing Section

Page 68 & 69

New updated Commissioning Checklist & Service Record Sheets

Page 70 & 71

New pages added, Flowchart for CO Level and Combustion Ratio Check on Commissioning a Condensing Boiler

Keston reserve the right to vary specication without notice

3Keston Combi - Installation and Servicing

general

Table 1 - General Data

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

Maximum Working Pressure (Sealed Systems) bar (lb/in

Maximum Domestic Hot Water Inlet Pressure bar (lb/in

Minimum Domestic Hot Water Inlet Pressure* bar (lb/in

) 2.5 (36.3)

) 10.0 (145)

) 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)

*Required for maximum ow rate. Boiler operates down to 2 l/min DHW delivery ** In areas of low water pressure the DHW restrictor can be removed

C - 13g/s 73ºC - 15g/s

Table 2 - Performance Data - Central Heating

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

Boiler Output :

Non Condensing kW 24.2 6.1 7.1

C Mean Water temp. (Btu/h) (82,600) (20,700) (24,100)

Condensing kW 25.6 6.4 7.5

C Mean Water temp. (Btu/h) (87,400) (21,800) (25,500)

Seasonal efciency* SEDBUK 2005

NOx Classication CLASS 5

/h 2.512 0.623 0.734

(ft

/h) (89) (22) (25.9)

91.1%

SEDBUK 2009

89%

88.9%

91%

Table 3 - Performance Data - Domestic Hot Water

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

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 Specic Rate l/min 14.5 16.9

/h 3.135 3.658

(ft

/h) (111) (129)

(gpm) (3.2) (3.7)

* The value is used in the UK Government’s Standard Assessment Procedure (SAP) for energy rating of dwellings. The test data from

which it has been calculated have been certied by a notied body.

Note. Gas consumption is calculated using a caloric value of 38.7 MJ/m

(1038 Btu/ft3) gross

or 34.9 MJ/m3 (935 Btu/ft3) nett

To obtain the gas consumption at a different caloric value:

a. For l/s - divide the gross heat input

(kW) by the gross C.V. of the gas (MJ/m

b. For ft

/h - divide the gross heat input (Btu/h)

)

Key to symbols

PMS = Maximum operating pressure of water

= A room sealed appliance designed for connection via ducts to

13 C53

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.

= An appliance designed for use on 2nd Family gas, Group H only.

by the gross C.V. of the gas (Btu/ft3)

c. For m

/h - multiply l/s by 3.6.

Keston Combi -

Installation and Servicing

general

KESTON Combi 30 & 35

Natural Gas only

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

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-certication that the boiler has been installed to comply with Building Regulations can be

demonstrated by completing and signing the Benchmark Commissioning Checklist.

Before installing this boiler, read the Code of Practice sheet at the rear of this book.

BENCHMARK COMMISSIONING CHECKLIST DETAILS

Boiler Page

Make and model ......................................................... 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

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 assistance see Technical Helpline on the back page

NOTE TO THE INSTALLER:

COMPLETE

THE BENCHMARK COMMISSIONING

CHECKLIST AND LEAVE THESE

INSTRUCTIONS WITH APPLIANCE

5Keston 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 efciency, condensing, combination gas boiler.

Note. Due to the high efciency 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.

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

• AirTerminalFinishingKit

• FlueSleeveKit

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 calorier 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 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

35 14.5 l/min at 35

When using the outside sensor provided please refer to page 27.

The DHW draw off rate specied 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

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.

C temperature rise.

C and 83oC, until DHW

Keston Combi -

Installation and Servicing

general

0.6m

Zone 0

Recessed window Zone 2

Ceiling

3G8913a

2.25m

Zone 1

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 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 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 certicated 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.

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.

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 modied 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, sufcient space may be required to

allow lifting access to the wall mounting plate.

• The boiler must be installed on a re resistant surface.

7Keston 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.

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.

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.

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”)

overow pipe. It is a universal tting to allow use of different

brands of pipework.

Keston Combi -

Installation and Servicing

general

395

198

155

30mm

Minimum Top Clearance

100395

400

700

FlueAir

2.5

2.5 from case

43 65 57 38

Gas Inlet

39 65

BOILER DIMENSIONS, SERVICES & CLEARANCES

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.

all dimensions in mm

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.

9Keston Combi - Installation and Servicing

SYSTEM REQUIREMENTS - Central Heating

general

Notes

a. The method of lling, relling, topping up or ushing sealed

primary hot water circuits from the mains via a temporary hose connection is only allowed if acceptable to the local water authority.

b. Antifreeze uid, corrosion and scale inhibitor uids suitable

for use with boilers having aluminium heat exchangers may be used in the central heating system.

General

1. The installation must comply with all relevant national and local

regulations.

2. The installation should be designed to work with flow temperatures of up to 86

3. All components of the system must be suitable for a working pressure of 3 bar and temperature of 110 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 difcult, 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 efciency 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 sufcient 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.

C. Extra care should

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)

25 1.6 1.8

50 3.1 3.7

75 4.7 5.5

100 6.3 7.4

125 7.8 9.2

150 9.4 11.0

175 10.9 12.9

190 11.9 14.0

200 12.5 14.7

250 15.6 18.4

300 18.8 22.1

For other system volumes multiply by the factor access 0.063 0.074

Water Flow Rate and Pressure Loss

Max CH Output kW 24.2

(Btu/h) (82,600)

Water ow rate l/min 17.3

(gal/min) (3.8)

Temperature Differential

Head available for m.w.g. 3.4

system (ft.w.g.) (11.1)

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.

Expansion vessel

volume (litres)

C 20

F) (36)

(

Keston Combi -

continued . . . . . .

Installation and Servicing

SYSTEM REQUIREMENTS cont’d

general

SYSTEM BALANCING

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

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.

5. Hard Water Areas

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.

Hot and cold water supplies to the shower are of equal pressure.

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.

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 each radiator.

3. Adjust the room thermostat and programmer to NORMAL settings.

C temperature drop at

WATER TREATMENT

CENTRAL HEATING

The Keston Combi range boiler has an ALUMINIUM alloy heat exchanger.

IMPORTANT. The application of any other treatment to this product may render the guarantee of Keston Invalid.

Keston recommend Water Treatment in accordance with the Benchmark Guidance Notes on Water Treatment in Central Heating Systems.

If water treatment is used Keston recommend only the use of SCALEMASTER GOLD 100, FERNOX, MBI, ADEY MC1 or

SENTINEL X100

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 articially softened water is NOT permitted.

4. Under no circumstances should the boiler be red

before the system has been thoroughly ushed.

inhibitors and associated water treatment

DOMESTIC HOT WATER

In hard water areas where mains water can exceed 200ppm

Total Hardness (as dened 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 articially

softened water, however, is not permitted. Keston recommend the use of Fernox Quantomat, Sentinel Combiguard or Calmag CalPhos I scale reducing devices together with scalemaster in-line scale inhibitor branded Ideal, which must be used in accordance with the manufacturers’ instructions.

For further information contact:

Fernox Cookson Electronics

Forsyth Road, Sheerwater, Woking, Surrey GU21 5RZ +44 (0) 870 601 500

Sentinel Performance Solutions

The Heath Business & Technical Park, Runcorn, Cheshire WA7 4QX Tel: 0800 389 4670 www.sentinel-solutions.net

Scalemaster Water Treatment Products

Emerald Way, Stone, Staffordshire ST15 0SR Tel: +44 (0) 1785 811636

Calmag Ltd.

Unit 3-6, Crown Works, Bradford Road, Sandbeds, Keighley, West Yorkshire BD20 5LN Tel: +44 (0) 1535 210 320

Adey Professional Heating Solutions

Gloucester Road, Cheltenham GL51 8NR Tel: +44 (0) 1242 546700

11Keston Combi - Installation and Servicing

BOILER ASSEMBLY - Exploded View

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

INSTALLATION

505

INSTALLATION

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

504

227

224

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 specic boiler range and output.

Check boiler serial letter code on data plate to obtain correct BCC.

503

313

215

214

206

205

211

512

204

308

309

217

306

506

115

219

303

304

307

116

229

218

401

301

228

231

112

507

120

108

127

111

128

131

119

121

118

110

136

113

114

117

223

314

326

332

325

324

302

105

135

106

107

203

106

104

Keston Combi - Installation and Servicing

D F

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

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

INSTALLATION

Flue Pack Contents

A Flue Adaptor B Air Spigot C Terminals - 2 off D Flue Sleeve E Wall Plate F Wall Seal G Outside Sensor H Screws - 4 off J Wall Plugs - 4 off

Keston Combi - Installation and Servicing

continued . . . . .

INSTALLATION

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.

Thefollowingpipeandttingsareapproved.

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.

FLUE OUTLET

continued............

Keston Combi - Installation and Servicing

INSTALLATION

TERMINAL POSITIONS

Flue Pipe

Elbow

Minimum Separation

140mm

Acceptable range of air

pipe siting

Terminal

Air Pipe

150mm

FLUE SYSTEM.... CONT’D

TERMINATION OF THE FLUE AND AIR

The ue and air pipes may terminate independently through any

external walls within the same dwelling except on opposing walls, within the maximum lengths shown in graph below.

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.

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.

SLOPE

‘Horizontal’ ue outlet pipework MUST slope at least 1.5 degrees (26mm per metre run) downwards towards the boiler. Pipework

can be vertical. Only swept elbows can be used.

Air inlet pipework can be truly horizontal or vertical, or sloping in a downward direction towards the boiler but in each case rain, etc.,

must be prevented from entering the pipe. Theremustbenotroughsinanyofthepipework,whetheritbeairinletorue outlet.

Keston Combi - Installation and Servicing

FLUE OUTLET

INSTALLATION

Bracket at each 1 metre

1.5m

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

2.5m

1.5m

0.15m

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

Accep table Op erating Area

Keston Combi 35 - Flue & Air Pipe Length

Flue Pip e Length [m]

Air Pipe Length [m]

15.65

14.5

Accep table Op erating Area

Keston Combi 30 - Flue & Air Pipe Length

Flue Pip e Length [m]

Air Pipe Length [m]

10.15

15.5

FLUE INSTALLATION EXAMPLE KESTON COMBI 30

FLUE INSTALLATION EXAMPLE KESTON COMBI 35

FLUE OUTLET

Keston Combi - Installation and Servicing

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.

FLUE TERMINATION POSITION

INSTALLATION

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

(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

boundary

Flue Minimum Spacing Air Minimum Spacing

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

D, E

12" 12" 12"

3" 8" 8"

6" 12" 12" 24" 48" 48" 60" 12"

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"

boundary

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: 1982.

Consideration must be given to Corgi/Gas Safe bulletin TB200/TB008 regarding ues in voids.

The boiler casing must always be correctly tted to the boiler when leaving the appliance operational.

External wall faces and any internal faces of cavity walls must be good.

AIR SUPPLY

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.

Keston Combi - Installation and Servicing

FLUE OUTLET

INSTALLATION

3G10030

Section through wall

Note. Check all of the hole positions before drilling.

Rear flue only 60mm diameter holes

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.

INSTALLATION

WALL MOUNTING TEMPLATE

The wall mounting template is located on the internal protective packaging.

Note.

The template shows the positions of the xing holes and the position of the air and ue connections. Care MUST be taken to ensure the correct holes are drilled.

1. Tape template into the selected position. Ensure squareness by hanging a plumbline as shown.

2. Mark onto the wall the following:

a The wall mounting plate screw positions (choose one from

each group).

b The position of the air and ue when exiting straight out of

the wall where the boiler is mounted.

Note. Mark the centre of the hole as well as the circumference.

3. Remove the template from the wall.

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.

Keston Combi - Installation and Servicing

esp9496

Example of fixing

FITTING THE WALL MOUNTING PLATE

INSTALLATION

MOUNTING THE BOILER

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.

1. Ensure the plastic plugs are removed from both the CH and DHW connections before mounting the boiler.

2. Lift the boiler onto the wall mounting plate (refer to the Introduction section for safe handling advice), locating it over the two tabs.

INSTALLATION

Keston Combi - Installation and Servicing

INSTALLATION

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.

FLUE OUTLET

Keston Combi - Installation and Servicing

INSTALLATION

FITTING THE FLUE SLEEVE

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. Afx ue terminal

9. During boiler test check that the ue end is free to expand and contract with exible wall seal.

Flue

Terminal

Flue Pipe

Flue Sleeve

Flue Sleeve Flange

Flexible

Wall

Seal

Wall

Plate

Keston Combi - Installation and Servicing

FLUE OUTLET

INSTALLATION

203

149

Condensate

Drain

Sink/basin/

bath or shower

Boiler

with 75mm

sealed

condensate

trap

Min Ø 19mm Internal pipe

Internal soil & vent stack

Boilers without 75mm sealed condensate trap must be fitted with a 75mm trap and visible air break

≥ 100

CONDENSATE DRAIN

This appliance is tted with a siphonic 75mm condensate trap

system that requires lling before operating the appliance for the rst time or after maintenance.

INSTALLATION

All condensate pipework should conform to the following: a. Where a new or replacement boiler is being installed, access to

an internal ‘gravity discharge’ termination should be one of the main factors considered in determining boiler location.

b. Plastic with push t or solvent connections.

c. Internal plastic pipe work a minimum of 19mm ID (typically

22mm OD)

d. External plastic pipe must be a minimum of 30mm ID (typically

32 OD) before it passes through the sleeved wall.

e. All horizontal pipe runs, must fall a minimum of 45mm per metre

away from the Boiler.

f. External & unheated pipe work should be kept to a minimum

and insulated with Class “O” waterproof pipe insulation.

g. All installations must be carried out in accordance to the

relevant connection methods as shown in the “Condensate installation diagrams” & BS6798:2009

h. Pipe work must be installed so that it does not allow spillage

into the dwelling in the event of a blockage (through freezing)

i. All internal burrs should be removed from the pipe work and any

ttings.

In order to minimise the risk of freezing during prolonged very cold spells, one of the following methods of terminating condensate

drainage pipe should be adopted.

Internal Drain Connections

Wherever possible, the condensate drainage pipe should be routed to drain by gravity to a suitable internal foul water discharge point such as an internal soil and vent stack or kitchen or bathroom waste pipe etc. See Figs 1 and 2.

Condensate Pump

Where gravity discharge to an internal termination is not physically possible or where very long internal pipe runs would be required to reach a suitable discharge point, a condensate pump of a

specication recommended by the boiler or pump manufacturer

should be used terminating into a suitable internal foul water discharge point such as an internal soil and vent stack or internal

kitchen or bathroom waste pipe etc. (g 3).

External Drain Connections

The use of an externally run condensate drainage pipe should only be considered after exhausting all internal termination options as described previously. An external system must terminate at a suitable foul water discharge point or purpose designed soak away. If an external system is chosen then the following measures must be adopted:

The external pipe run should be kept to a minimum using the most direct and “most vertical” route possible to the discharge point, with no horizontal sections in which condensate might collect.

- For connections to an external soil/vent stack see Fig 4. Insulation measures as described should be used.

- When a rainwater downpipe is used, an air break must be installed between the condensate drainage pipe and the

downpipe to avoid reverse ow of rainwater into the boiler should the downpipe become ooded or frozen, see Fig 5.

- Where the condensate drain pipe terminates over an open foul drain or gully, the pipe should terminate below the grating level, but above water level, to minimise “wind chill” at the open end. The use of a drain cover (as used to prevent blockage by leaves) may offer further prevention from wind chill. See Fig 6.

- Where the condensate drain pipe terminates in a purpose designed soak away (see BS 6798) any above ground condensate drain pipe sections should be run and insulated as described above. See Fig 7

Unheated Internal Areas

Internal condensate drain pipes run in unheated areas, e.g. lofts basements and garages, should be treated as external pipe.

Ensure the customer is aware of the effects created by a frozen condensate and is shown where this information can be found in the user manual.

Figure 1 - Connection of Condensate Drainage Pipe to Internal Soil & Vent Stack

Boiler

with 75mm

sealed

condensate

trap

Boilers without 75mm sealed condensate trap must be fitted with a 75mm trap and visible air break

Min Ø 19mm Internal pipe

Soil & vent stack

Minimum connection height up to 3

≥ 450

storeys

Figure 2 - Connection of a Condensate Drainage Pipe Downstream of a Sink, Basin, Bath or Shower Water Trap to Internal Soil Vent Stack

continued . . . . .

Keston Combi - Installation and Servicing

CONDENSATE DRAIN - CONT’D.......

INSTALLATION

Figure 3 - Connection of a Condensate Pump Typical Method (see manufacturers detailed instructions)

Boiler

with 75mm

sealed

condensate

trap

Min Ø 19mm Internal pipe

Condensate pump (Install in accordance with manufacturers instructions)

Visible air break

Figure 5 - Connection of a Condensate Drainage Pipe to an External Rainwater Downpipe (only combined foul/rainwater drain)

Figure 4 - Connection of condensate Drainage Pipe to External Soil & Vent Stack

Boiler

with 75mm

sealed

condensate

trap

Min Ø 19mm Internal pipe

Boilers without 75mm sealed

condensate trap must be fitted with

a 75mm trap and visible air break

Min Ø 30mm

Internal pipe

Water/weather proof insulation

Soil & vent stack

Minimum connection

≥ 450

height up to 3 storeys

Figure 6 - Connection of Condensate Drainage Pipe Upstream of a Sink, Basin, Bath or Shower Waste Trap to External Drain, Gulley or Ranwater Hopper

INSTALLATION

Boiler

with 75mm

sealed

condensate

Min Ø 19mm Internal pipe

Min Ø 30mm Internal pipe

trap

Terminated and cut at 45º

43mm 90º male/ female bend

Water/ weather proof insulation

combined foul/ rain water drain

External air break

Air gap

68mm Ø PVCU Strap on fitting

Figure 7 - Connection of a Condensate Drainage Pipe to an External Purpose Made Soak Away.

Boiler

with 75mm

sealed

condensate

trap

Min Ø 19mm Internal pipe

Min Ø 30mm Internal pipe

Water/Weather proof insulation

Max 3m external pipework

Boiler

with 75mm

sealed

condensate

trap

Min Ø 19mm Internal pipe

Sink, basin, bath or

shower with integral

overflow and 75mm trap

Visible air break

≥ 100

at plug hole

Minimum 30mm

internal pipe

Water/ weather proof insulation

45º pipe

termination

≥ 25 Below grate

Boilers without 75mm sealed condensate trap must be fitted with a 75mm trap and visible air break

2 rows of three Ø12mm holes 25mm centres, 50mm from the bottom of the tube, facing

away from the house

Keston Combi - Installation and Servicing

≥ 300

≥ 500

≥ 25

Limestone chippings

Blue

Handle

Black Handle

Yellow

Handle

Filling

Loop

CH Flow

DHW

Outlet

Gas

Supply

DHW

Inlet

Return

Safety

Drain Valve

CONNECTIONS & FILLING

INSTALLATION

NOTES.

Ensure all boss blanking plugs are removed before connecting hardware. Each valve must be tted to the correct boss as shown in the picture.

Ensure each union is tted with bre seals provided.

Do not subject any of the isolating valves to heat as the seals may be damaged.

WATER CONNECTIONS CH

FILLING

1. Connect the CH ow service valve (black handle) and

copper tail provided in the hardware pack to the threaded boss connection provided at the lower rear of the boiler.

2. Connect the CH rtn. valve (black handle) and copper tail.

INSTALLATION

3. If connecting the boiler to heating loads in excess of

60,000 Btu/h, connecting ow and return heating systems

pipework must be sized in 28mm diameter at the point of pipe connection to the boiler tails. use 22mm x 28mm

FILLING

IMPORTANT -whenlling:

When lling, there may be a slight water leak from the air vent

therefore electrical connections should be protected.

1. Ensure Filling Loop is connected

2. Ensure dust cap on auto air vent is slackened off (refer to

pipe adaptors as appropriate.

3. Check all isolation handles on all water connections are in

WATER CONNECTIONS DHW

1. Fit the DHW inlet service valve (blue handle) and copper tail

to the threaded boss connection ensuring the seal provided is correctly located.

2. Fit the DHW outlet pipe tail to DHW outlet connection, ensuring the seal provided is correctly located.

3. Fit the lling loop provided between the DHW inlet valve and

the CH return valve

4. Open handle  on the lling loop, then slowly open handle

5. Once pressure gauge dial reads between 1 - 1.5 bar turn the

6. Disconnect lling loop at the LH side, ensuring top hat

7. Connect extended blanking cap and top hat washer to lling

GAS CONNECTION

IMPORTANT. The gas service cock is sealed with a non-metallic

blue bre washer, which must not be overheated when making

capillary connections. Refer to Frame 1 for details of the position of the gas connection.

For additional gas supply info refer to “Gas Supply” on page 8.

Note. Fully open all DHW taps and ensure water is

owing freely. Once satised close all taps.

Note. The domestic hot water ow rate is automatically regulated to a maximum of 12.4 l/m (2.8 gpm)

Frame 66).

the open position.

 until pressure gauge reads between 1 to 1.5 bar.

lling loop isolation valves back to the closed position.

washer is retained and screw on blanking cap.

loop pipe.

Handle 

(Shown in closed position)

SAFETY VALVE DRAIN

The safety valve connection, located at the bottom right-hand side of the boiler, comprises a 15mm diameter stub pipe.

The Installer to provide a compression joint on the end of the stub pipe. This assists with pipe removal when servicing.

The discharge pipe should be positioned so that the discharge of water or steam cannot create a hazard to the occupants of the premises or damage the electrical components and wiring.

Note that all isolation handles are shown in the open postion.

Handle 

(Shown in closed position)

Keston Combi - Installation and Servicing

ELECTRICAL CONNECTIONS

INSTALLATION

WARNING. This appliance MUST be earthed.

A mains supply of 230Vac ~ 50 Hz is required.

The fuse rating should be 3A. All external controls and wiring must be suitable for mains voltage.

Wiring external to the boiler MUST be in accordance with the current I.E.E. (BS.7671) Wiring Regulations and any local regulations.

INTERNAL WIRING

The Keston Combi boiler comes pre-tted with 1.8m of

mains cable. This must be connected to a permanent live supply and NOT switched by thermostats/programmers. For installers wishing to change this cable refer to Frame

26.

The Keston Combi boiler comes pre-tted with a link wire

between the room thermostat/Timer connections on the terminal strip. This creates a permanent call for heat and must be removed when adding a room thermostat/ programmer.

The terminal block cover carries two spare fuses for the main PCB.

Wiring should be 3 core PVC insulated cable, not less than

0.75mm2 (24 x 0.2mm), and to BS 6500 Table 16. For IE reference should be made to the current ETCI rules for electrical installations.

Connection must be made in a way that allows complete isolation of the electrical supply such as a double pole switch having a 3mm (1/8”) contact separation in both poles. The means of isolation must be accessible to the user after installation.

INSTALLATION

To add thermostat/programmer:

1. Isolate the mains supply to the boiler.

2. Remove the front panel. Refer to Frame 39.

3. Swing the control box down into the servicing position.

Refer to Frame 45.

4. Route incoming cables through the grommets in bottom panel (note, grommets are ‘blind’ and will require puncturing) and secure using clamps and screws provided in hardware pack.

5. Pull off rubber terminal block cover.

6. Connect wires to terminal block, as shown below

7. Re-assemble in reverse order.

Spare PCB fuses

Keston Combi - Installation and Servicing

continued . . . .

INSTALLATION

3G9560

FROST STAT (

OPTIONAL

)

ROOM STAT/ TIMER

Room Stat or Prog. Room Stat

Optional

Frost Stat

DIAGRAM A

Internal Timer or Programmable Room Stat

3G9561

FROST STAT (

OPTIONAL

)

ROOM STAT/ TIMER

Room Stat

Optional

Frost Stat

DIAGRAM B External Timer

3G9707a

FROST STAT (

OPTIONAL

)

ROOM STAT/ TIMER

OpenTherm Harness

Weather Compensation

Optional

Frost Stat

Outside

Sensor

DIAGRAM C

Weather Compensation Kit

Timer

INTERNAL WIRING.... CONT’D

Keston offer 2 kits as follows: (see individual kits for installation instructions)

Electronic Timer (7 day) kit - 7 day electronic CH timer ts into the control box of the boiler. This can be tted in conjunction

with a room thermostat. Features English language installation help messages.

INSTALLATION

(1) ROOM THERMOSTAT WITH INTERNAL BOILER TIMER OR (2) PROGRAMMABLE ROOM THERMOSTAT

1. Remove link wire between room stat/timer terminals.

2. Connect room stat across terminals as shown in diagram A

3. If room stat has a neutral connection, connect this to terminal

N (load) in the fused spur.

ROOM THERMOSTAT + TIMER

1. Remove link wire between room stat/timer terminals.

2. Connect room stat and programmer in series as shown in diagram B.

3. If room stat has a neutral connection, connect this to terminal N (load) in the

fused spur.

FROST THERMOSTAT

If parts of the system are vulnerable to freezing or the programmer is likely to be

left off during cold weather, a frost stat should be tted in conjunction with a pipe

thermostat.

1. Position the frost thermostat in a suitable position, i.e. area vulnerable to freezing.

2. Connect frost stat across terminals marked frost stat shown in diagrams A & B.

WEATHER COMPENSATION KIT

The two wires from the weather compensation kit (outside sensor), must be connected into the two right hand terminals as shown in diagram C.

Keston Combi - Installation and Servicing

INSTALLATION

3G10011

REPLACING PRE-FITTED MAINS CABLE

If it is necessary to use an alternative mains cable to the one pre-tted

then use the following guide.

Replacement wiring should comply with notes in Frame 23.

1. Isolate the mains supply to the boiler.

2. Remove the front panel. Refer to Frame 39.

3. Swing the control box down into the service position. Refer to

frame 45.

4. Remove the live, neutral and earth wires from the terminal block.

5. Loosen the cable clamp and withdraw the mains cable.

6. Route replacement cable back through the cable clamp and

grommet and re-tighten to provide cord anchorage.

7. Connect the live, neutral and earth wires to the terminal strip.

When making the mains electrical connections to the boiler it is

important that the wires are prepared in such a way that the earth conductor is longer than the current carrying conductors, such that if the cord anchorage should slip, the current carrying conductors become taut before the earthing conductor.

8. Swing the control box back up into the operating position and re-t

the front panel ensuring a good seal is made.

INSTALLATION

FITTING THE WEATHER COMPENSATION KIT - SUPPLIED AS STANDARD

This kit provides the facility to apply outside air temperature control to the boiler

water ow temperature which provides energy savings. The outside sensor provided

measures outside air temperature and sends a signal to the boiler, which adjusts the

maximum boiler ow temperature in response. If outside air temperature is greater than the system design temperature, the boiler ow temperature is reduced providing running

cost savings. The boiler will operate in the condensing mode more frequently increasing savings.

Once the sensor is tted it is automatically detected.

The sensor operation may be congured by adjustment of the boiler operating

parameters, if necessary.

Kit Contents

A. Outside Air Sensor

FITTING THE KIT

Note. A timer should be tted to the system so that CH will be switched off when appropriate.

Fitting the sensor

The air sensor should be located on an external wall of the building to be heated. Fix the sensor to a north/north-east facing wall

to avoid direct radiation from the sun. The air sensor should be located to avoid any heating effect from the boiler ue.

To x the air sensor to the wall, unscrew the sensor box plastic cover and screw/plug the sensor body to the wall.

Wire a twin core 0.5mm length between sensor and boiler should be no greater than 20m. Note that this connection is safety extra low voltage. It is not necessary for the person carrying out the wiring to be approved to Part P of the Building Regulations.

Avoid running this cable alongside mains voltage cables.

cable from the sensor to the boiler through an RH grommet located on the underside of the boiler. Cable

Wiring the Weather Compensation Kit to the Keston Combi.

1. Isolate the electricity supply to the boiler.

2. Remove the boiler front panel (refer to

boiler installation instructions).

3. Hinge down the control box.

4. Connect the sensor wiring into the RHS of

the 4 way terminal block and secure with a

Keston Combi - Installation and Servicing

cable clamp.

5. Re-assemble in reverse order.

INSTALLATION

CH OPERATION

The On and Off time control of central heating should be controlled by a separate timer. This can be a standard unit or either of the options available from Keston Combi range.

During programmed On times the Central Heating Radiator Flow Temperature is controlled by the boiler relative to the Outside Temperature as shown in the following diagram.

INSTALLATION

Weather Compensation Control / Room Setpoint = +20ºC

Heating slope

CH Temperature Setpoint [C]

20 10 0 -10 -20 -30 -40

2.5 2.2 2.0 1.8 1.6 1.4 1.2 1.0

Outside Temperature [ºC]

100

The Room temperature can be adjusted using the Central Heating Temperature Control Knob on the boiler as follows. Essentially rotating the knob clockwise increases the room temperature and rotating the knob anti-clockwise decreases the room temperature.

If the Central Heating Temperature Control Knob is rotated fully clockwise then for an Outside Temperature of 15°C a Flow Temperature of 40°C will be provided. For an Outside Temperature of 0°C a Flow Temperature of 78°C will be provided with the relationship varying lineally in between these 2 points (line on the graph 2.5)

If the Central Heating Temperature Control Knob is in its mid position then for an Outside Temperature of 15°C a Flow Temperature of 36°C will be provided. For an Outside Temperature of 0°C a Flow Temperature of 65°C will be provided with the relationship varying lineally in between these 2 points (line on the graph between 1.6 and 1.8)

If the Central Heating Temperature Control Knob is rotated fully anti-clockwise then for an Outside Temperature of 15°C a Flow Temperature of 30°C will be provided. For an Outside Temperature of 0°C a Flow Temperature of 44°C will be provided with the relationship varying lineally in between these 2 points (line on the graph 1.0)

Keston Combi - Installation and Servicing

INSTALLATION

3G9990a

Room Stat Frost Stat

Mains In

Programmable Room Stat

Room Stat Frost Stat

Mains In

Use of General Live for Room Stat

Programmable Room Stat

Room Stat

Optional

Frost Stat

Optional

Frost Stat

EXTERNAL ELECTRICAL CONTROLS

Wiring External to the Boiler

The fuse rating should be 3A.

Wiring external to the boiler MUST be in accordance with the current I.E.E. (BS.7671) Wiring Regulations and any local regulations.

Frost Protection

If parts of the pipework run outside the house or if the boiler will be left off for more than a day or so then a frost thermostat should be wired into the system.

This is usually done at the programmer, in which case the programmer selector switches are set to OFF and all the other controls MUST be left in the running position.

The frost thermostat should be sited in a cold place but where it can sense heat from the system.

Note. If the boiler is installed in a garage it may be necessary to t a pipe thermostat, preferably on the return pipework.

Earths are not shown for clarity but must never be

omitted.

INSTALLATION

OpenTherm Programmable Room Temperature Control

Note. These terminals MUST ONLY be connected to an OpenTherm Controller, (such as the Keston Chronothern Room Controller (c.17.4.21.00.0). Connecting any other device / control wiring may destroy the primary PCB.

1. Isolate the mains supply to the boiler.

2. Remove the front panel. Refer to Frame 39.

3. Swing the control box down into the servicing position. Refer

4. Remove the control box cover. Refer to Frame 57, no’s 3

5. Unclip the 3 way in-line connector containing 2 purple wires

6. Connect this 3 way connector to the 3 way connector

7. Connect the two wires from the OpenTherm Programmable

8. Re-assemble in reverse order.

to Frame 45.

and 4.

and 2 red wires.

containing 2 purple wires wired from the 4 way terminal block.

Room Temperature Control to the two LH connections of the terminal block as shown.

Keston Combi - Installation and Servicing

Flue

Thermostat

Timer

X1X2X3

X5X6X8

2345612345123456879

1234123456

12345123456789

1011

Water

Flow

Turbine

Water

pressure

Sensor

PCB

Flow

Thermistor

Return

Thermistor

Earth

y/g

b br

y/g

Service

Connector

Selv Timer

- blue

- black

- brown

- red

- pink

- yellow

- white

- yellow/green

- grey

- orange

- violet

bbkbrrpyw

y/ggor

KEY

p y

Flame

Sensor

Electrode

Fan

y/g

Spark

Electrode

Spark

Generator

Gas

Valve

bk b

Divertor

Valve

Pump

y/g

Frost

Stat

Main

Supply

Room

Stat

r v

y/g

Weather

Compensation

Opentherm

Room Thermostat

INSTALLATION

WIRING DIAGRAM

INSTALLATION

Keston Combi - Installation and Servicing

Safety

Drain Valve

Blue

Handle

Gas Supply

CH Return

DHW Inlet

Gas Pressure

Test Point

COMMISSIONING AND TESTING

INSTALLATION

A. Electrical Installation

1. Checks to ensure electrical safety should be carried out by a

competent person.

2. ALWAYS carry out the preliminary electrical system checks, i.e. earth continuity, polarity, resistance to earth and short circuit, using a suitable test meter.

After wiring the boiler, all grommets in the bottom panel MUST

3. be in place to ensure that the boiler case sealing is maintained.

WARNING. Whilst effecting the required gas tightness test and purging air from the gas installation,

open all windows and doors, extinguish naked lights and DO NOT SMOKE.

GENERAL

Please Note: The combustion for this appliance has been checked, adjusted and preset at the factory for

operation on the gas type dened on the appliance

data plate. No measurement of the combustion is necessary. DO NOT adjust the air/gas ratio valve.

Having checked:

- That the boiler has been installed in accordance with these instructions.

- The integrity of the ue system and the ue seals,

as described in the Flue Installation section.

Proceed to put the boiler into operation as follows:

CHECK THE OPERATIONAL (WORKING) GAS INLET PRESSURE

Set up the boiler to operate at maximum rate by opening hot tap to maximum

ow.

With the boiler operating in the maximum rate condition check that the operational (working) gas pressure at the inlet gas pressure test point complies with the requirements - refer to “Gas Supply” on page 8.

Ensure that this inlet pressure can be obtained with all other gas appliances in the property working.

“SERVICE REQUIRED” Function

When the boiler has been installed for more than 1 year the following message will appear on the screen:

“12 Month Service Interval Request”

To cancel this message move the CH Temperature Control Knob away from the maximum position. Then move the knob to the maximum position, away from the maximum position and back into the maximum position again within 3s.

“Service Mode” will be shown on the screen, this will disappear after 5 mins.

“AIR VENTING” Function

The Air Venting function should not be required for this boiler.

• The Air Venting function operates for 5 mins as follows:

• Pump On for 50s, Pump Off for 10s (repeats 5 times)

• Diverter valve in hot water position for 30s then CH position for

30s (repeats 5 times)

• The function ends automatically.

To activate the Air Venting function proceed as follows:

Turn the DHW temperature control knob fully anti-clockwise.

Turn the CH ow temperature control knob fully anti-clockwise.

Turn and hold the Mode Knob in the Reset position for more than 5s and then turn it to the Winter or Summer position

The boiler will display “Installer Mode”

If no faults have occurred the boiler will display “No Faults”

If any faults have occurred a list of faults up to a maximum of 10 including the type of fault and how long ago it occurred will be shown.

The boiler will then display the current values of ow temperature, return temperature, domestic hot water temperature, DHW ow rate

and diverter valve position.

Next the boiler will display

“Venting Boiler OFF” - “For Activation change Pre-heat Mode”

Now move the pre-heat knob and the Air Venting Function will begin, the boiler will display:

“Venting Boiler Off” - “Pump and Diverter Valve Cycling” - Duration 5 mins” - “Reset to End”

B. Gas Installation

1. The whole of the gas installation, including the meter,

should be inspected and tested for tightness and purged in accordance with the recommendations of BS. 6891. In IE refer to IS.813:2002.

2. Purge air from the gas installation by the approved methods only.

INSTALLATION

As part of the commissioning process, the combustion of this appliance must be checked

and the Benchmark Checklist completed. A ow chart to assist is provided on page 71.

IT IS A CONDITION OF THE MANUFACTURERS WARRANTY THAT THE BENCHMARK

COMMISSIONING CHECKLIST IS FULLY COMPLETED AND LEFT WITH THE APPLIANCE

Keston Combi - Installation and Servicing

ATTENTION !

A B E F C D

INITIAL LIGHTING

Legend

A. Pre-heat On/off B. DHW temperature control C. CH temperature control D. Off/Summer/Winter/Reset Control E. Boiler Status F. Burner ‘on’ indicator G. CH Flow Isolating Valve H. Pressure Gauge J. Gas Inlet Pressure Test Point K. Gas Service Cock

INSTALLATION

L. DHW Inlet Valve M. CH Return Isolating Valve N. DHW Outlet

INSTALLATION

1. Check that the system has been lled and that the boiler is not

airlocked. Ensure the automatic air vent cap is open. Refer to Frame 22.

Note.

It is important the burner is not operated before the system is fully vented of air. If it is necessary to operate the appliance pump to assist venting of the air this must be done with the gas service cock turned off.

2. Ret the boiler front panel. Refer to Frame 39.

3. Check that the drain cock is closed and that the CH and DHW

isolating valves (M, L and G) are OPEN.

4. Check that the electrical supply is OFF.

5. Check that the boiler mode control knob (D) is off.

6. Check that the gas service cock (K) is OPEN.

7. Slacken the screw in the inlet pressure test point (J) and connect a gas pressure gauge via a exible tube.

8. Switch the electricity supply ON and check all external controls

are calling for heat.

DOMESTIC HOT WATER

11. With the boiler ring, set the DHW Temp Control knob (B)

to maximum and fully open a DHW tap.

The boiler will continue to run and the display (E) will

show “Hot Water” - “Temperature XX

C” - “High

Efciency”.

12. Ensure that with the boiler operating the dynamic gas pressure is able to obtain maximum output. Refer to Table

IMPORTANT The gas input to the burner is regulated by the gas valve

accordingtotheairowproducedbythefan.ItisNOT user-adjustable. Any interference to sealed settings on the gas valve will adversely affect operation and render our warranty void.

For additional gas supply information refer to “Gas Supply” on page 8

13. Turn off the DHW tap.

CENTRAL HEATING

9. Set the CH temp control (C) to max and turn the mode control

knob (D) to , ensure the timer/room stat are on. The boiler control will now go through its ignition sequence until the burner is established.

10. If the boiler does not light the following messages will be displayed in rotation “Ignition Lockout” - “1 Check

other gas appliances” - “2 Reset boiler” - “3 Contact

installer”. After 5 attempts the boiler will lock out and carry on displaying the messages. Reset the boiler (refer to Frame 40B). The boiler will repeat its ignition sequence. If reset

Note. The temperature displayed “XXºC” is that measured at that moment, not the set temperature.

occurs 5 times within 15 minutes then “Too many resets” will be shown. If power is removed this will be reset.

C”.

When the burner is established the BLUE ‘Burner On’ neon

(F) will be illuminated, the LCD will display “Central Heating”

and “Radiator Temp XX

Note. The boiler incorporates a fan overrun cycle which MUST NOT be prematurely interrupted by isolation of the mains electricity supply.

continued. . . . .

Keston Combi - Installation and Servicing

INSTALLATION

NORMAL OPERATION MESSAGE 1 MESSAGE 2 MESSAGE 3

Mode knob in standby position and no heat demand

Standby mode For hot water turn mode

knob clockwise

For central heating turn mode knob clockwise twice

Mode knob in summer position and no heat demand

Summer mode For central heating turn

mode knob clockwise

Mode knob in winter position and no heat demand

Winter mode Timer or room stat off

Domestic hot water operation Hot water Te mperature 64ºC High efficiency

Central heating operation Radiator Temp 80ºC High efficiency

Pre-heat operation Pre heat

Central heating

Temperature 59ºC High efficiency

Boiler frost protection Boiler frost protection Te mperature 5ºC

Pump overrun Pump overrun

Fan post-purge Fan post-purge

High efficiency

Note. High efficiency will not be shown for central heating operation if the central heating flow temperature knob is set to greater than 73ºC.

3G9711

NORMAL OPERATION MESSAGE 1 MESSAGE 2 MESSAGE 3

Pre-heat knob moved to off position Pre heat off

Pre-heat knob moved to on position Pre heat on

DHW temperature knob moved 64ºC DHW temp Hot water

temperature 64ºC

CH temperature knob moved 80ºC CH temp Maximum radiator

temperature 80ºC

May not be achieved for high flow rates in winter

Mode knob moved to standby position Central heating off Hot water off

Mode knob moved to summer position Summer mode

Standby mode

Central heating off Hot water on

Mode knob moved to winter position Winter mode Central heating on

Mode knob moved to reset position Reset

Hot water on

3G9712

INITIAL LIGHTING . . . . CONT’D

THE DISPLAY

The user control has one neon and one display to inform the user about the status. The display will show the status of the boiler.

The neon will show the status of the ame. If no ame is detected the neon is off. When the ame is detected the neon will be lit

permanently.

The display scrolls through a maximum of 3 messages under any operational condition as shown below.

Notes: Boiler frost protection - boiler res if temperature is below 5º C. The temperatures shown below are for illustration purposes only. The measured temperatures will be shown on the boiler.

DISPLAY FUNCTIONS IN NORMAL OPERATION

INSTALLATION

DISPLAY FUNCTIONS - SETTINGS CHANGED

Keston Combi - Installation and Servicing

INSTALLATION

MESSAGE 1 MESSAGE 2 MESSAGE 3

LIST OF FAULTS

Fault 1 (latest fault) Low water pressure 2 days ago

Fault 2 No water flow lockout

Fault 3 Overheat lockout 384 days ago

78 days ago

MESSAGE 1

CURRENT VALUES

Flow temp 80ºC

Return temp 60ºC

DHW temp 64ºC

DHW flow rate 8 l/min

Diverter valve DHW position

3G9714

A B E F C D

INITIAL LIGHTING . . . . CONT’D

INSTALLER MODE

Installer Mode is entered as follows:

1. Turn the DHW temperature control knob full anti-clockwise.

2. Turn the CH ow temperature control knob full anti-clockwise.

3. Turn and hold the mode knob in the reset position for more than 5 secs and then turn it to the Winter or Summer position.

The boiler will display “Installer mode”.

If no faults have occurred the boiler will display “No faults”.

If any faults have occurred a list of faults up to a maximum of 10 including the type of fault and how long ago it occurred will be shown in the following format.

INSTALLATION

The boiler will then display the current values of

ow temperature, return temperature, domestic hot water temperature, DHW ow rate and diverter valve

position in the following format:

Note.

If you would like to hold one of the values on the display to watch its behaviour then turn the reset knob to the reset position while it is displayed and hold it there.

Finally the display will operate in one of two modes. If there is a fault then more extensive corrective actions will be shown than are usually displayed for the end user. If there is not a fault then the information displayed for current operating states will also be more extensive than is usually displayed for the end-user (pre-purge, ignition and post purge for example).

Installer mode automatically ends after 10 mins or by moving the mode knob to the standby position.

RESET PROCEDURE

To reset boiler, turn the mode control knob (D) to reset position and immediately turn knob back to required setting. The boiler will repeat the ignition sequence if a heat demand is present.

Legend

A. Pre-heat On/off B. DHW temperature control C. CH temperature control

D. Off/Summer/Winter/Reset Control E. Boiler Status F. Burner ‘on’ indicator

Keston Combi - Installation and Servicing

INSTALLATION

GENERAL CHECKS

Make the following checks for correct operation in:

DOMESTIC HOT WATER (DHW) MODE

1. Fully open all DHW taps in turn and ensure that water ows

freely and that the mode knob is either in summer or winter position. The boiler will display

“Hot Water” - “Temperature XX

C” - “High

Efciency”

where the temperature shown is the current Domestic Hot

Water temperature.

When the burner is lit the light above the display will be on.

2. Close all taps except the furthest one from the boiler and

check that the boiler is ring at maximum rate.

This is factory set to give a DHW temperature rise of approximately 35

C at the ow rate stated on page 6 under

“operation”.

3. Reduce the DHW draw-off rate to about 3 l/min (0.7gpm) and check that the boiler modulates to deliver DHW at approximately 64

C (with the DHW temperature control

knob set to maximum).

4. Close the DHW tap and check that the main burner extinguishes. The pump should overrun for 60 seconds during which the boiler will display “Pump overrun”. The fan will then continue to run for a further 3 minutes during which the boiler will display “Fan Post Purge” after which the boiler will display one of the following “Standby mode”

- “Summer mode” - “Winter Mode” depending on the position of the mode knob.

Note. On systems in excess of 2 bar inlet pressure a water pressure governor may be required to prevent water noise.

CH & DHW MODE

1. Ensure the CH controls are calling for heat and that the

boiler mode knob is in the winter position and the CH ow

temperature control knob is in the maximum position. The Boiler will display

“Central Heating” - “Radiator Temp XXC”

where the temperature shown is the current ow temperature.

When the burner is lit the light above the display will be on.

2. Fully open the DHW tap and check that hot water is delivered. The boiler will display “Hot water” - Temperature XX

C”

- High Efciency”

3. Gas Rate

Check the boiler gas rate when the boiler is at full DHW

output. Check at the gas meter, with no other appliance in use. Refer to Tables 2 and 3 for gas rates.

4. Close the DHW tap. The burner should remain on and the boiler will display “Central heating” - “Radiator temp

XXC”.

5. Set the central heating external controls to off. The burner will go off and the fan and pump continue to run for 4 minutes. The boiler will display “Pump overrun” after which the boiler will display one of the following: “Standby mode”

- “Summer mode” - “Winter mode” depending on the position of the mode knob.

6. Check the correct operation of the timer (if tted) and all other

system controls. Operate each control separately and check that the main burner responds.

INSTALLATION

WATER CIRCULATION SYSTEM

1. With the system COLD, check that the initial pressure

is correct to the system design requirements.

For pre-pressurised systems, this should be 1.0 bar.

2. With the system HOT, examine all water connections for soundness. The system pressure will increase with temperature rise but should not exceed 2.5 bar.

3. With the system still hot, turn off the gas, water and electricity supplies to the boiler and drain down to

complete the ushing process.

Note: A ushing solution should be used during the

ushing procedure. Flushing solutions: Fernox Superoc, Sentinel X300 (new systems) or X400 (existing systems). Refer to Frame 5.

4. Rell and vent the system, add inhibitor (see Frame

5), clear all air locks and again check for water soundness.

5. Reset the system initial pressure to the design requirement.

6. Balance the system. Refer to Frame 4.

7. Check the condensate drain for leaks and check that

it is discharging correctly.

Note. The temperature displayed “XXºC” is that measured at that moment, not the set temperature.

8. Finally, set the controls to the User’s requirements.

Notes.

1. If the pump has not operated in the last 24 hours it will run briey to prevent seizure

2. If the diverter valve has not operated in the last 24 hours it will be operated briey to prevent seizure. These two operations will not occur at the same time.

WATER TEMPERATURES

Temperatures can be selected using the CH and DHW thermostats.

Knob Setting CH Flow Temp DHW Outlet Temp

C (oF)

Max 80 (176) 64 (147)

Min 45 (113) 40 (104)

Keston Combi - Installation and Servicing

INSTALLATION

HANDING OVER

After completing the installation and commissioning of the system the installer should hand over to the householder by the following actions:

1. Make the householder aware that the user instructions

are located in the pocket in the drop down door and explain his/her responsibilities under the relevant national regulations.

2. Explain and demonstrate the lighting and shutting down

INSTALLATION

procedures.

3. The operation of the boiler and the use and adjustment of all system controls should be fully explained to the householder, to ensure the greatest possible fuel economy consistent with the household requirements of both heating and hot water consumption.

Advise the User of the precautions necessary to prevent

damage to the system and to the building, in the event of the system remaining inoperative during frosty conditions.

4. Explain the function and the use of the boiler heating and domestic hot water controls.

Explain that due to system variations and seasonal

temperature uctuations DHW ow rates/temperature

rise will vary, requiring adjustment at the draw off tap. It is therefore necessary to draw the users attention to the section in the Users Instructions titled “Control of Water Temperature” and the following statement:

“Additionally, the temperature can be controlled by

the user via the draw-off tap: the lower the rate the higher the temperature, and vice versa”.

5. Explain the function of the boiler fault mode.

Emphasise that if a fault is indicated, the boiler should be

turned off and a Gas Safe Registered Engineer consulted. In IE contact a Registered Gas Installer (RGII).

6. Explain and demonstrate the function of time and temperature controls, radiator valves etc., for the economic use of the system.

7. If a timer is tted draw attention to the timer Users

Instructions and hand them to the householder.

8. Loss of system water pressure

Explain that the dial underneath the boiler indicates the

central heating system pressure and that if the normal COLD pressure of the system is seen to decrease over a period of time then a water leak is indicated. Explain the re-pressurising procedure and if unable to re-pressurise or if the pressure continues to drop a registered local heating installer should be consulted.

9. Explain boiler reset procedure (refer to Frame 35).

10. After installation and commissioning please complete

the handover to the customer. For IE, its is necessary to complete a “Declaration of Conformity” to indicate compliance to I.S. 813:2002.

IMPORTANT

11. A comprehensive service should be carried out ANNUALLY.

Stress the importance of regular servicing by a Gas Safe

Registered Engineer. In IE servicing work must be carried out by a Registered Gas Installer (RGII).

12. Inform the householder of the guarantee form and the

requirement to register it to receive the full benet of the

warranty.

Commissioning Checklist before

Keston Combi - Installation and Servicing

SERVICING

SERVICING SCHEDULE

For the very latest copy of literature for specication & maintenance practices, visit our website www.keston.co.uk, where you will

be able to download the relevant information.

WARNING. Always turn OFF the gas supply at the gas service cock, and switch OFF and disconnect the electricity supply to the appliance before servicing.

Combustion testing must be carried out by a competent person using a combustion analyser conforming to BS7927.

To ensure the continued safe and efcient operation of the appliance it is recommended that it is checked at regular intervals and

serviced as necessary. The frequency of servicing will depend upon the installation condition and usage but should be carried out at least annually.

It is the law that any service work must be carried out by a Gas Safe Registered Engineer. In IE service work must be carried out by a Registered Gas Installer (RGII).

INSPECTION

1. Light the boiler and carry out a pre-service check, noting any

operational faults.

2. Check the ue terminal (and terminal guard if tted) is undamaged

and clear of any obstruction.

3. Check all water and gas joints for signs of leakage. Remake any

suspect joints ensuring a gas tightness check is carried out if

applicable and the water system is correctly relled, vented and

re-pressurised.

CLEANING PROCEDURE

Note. In order to carry out either servicing or replacement of

components the boiler front panel must be removed. Refer to Frame 39.

1. Clean the main burner. Refer to frame 41.

2. Clean the heat exchanger & condensate trap/siphon. Refer to

Frames 41 & 42.

3. Check the main injector for blockage or damage. Refer to Frame

40.

4. Check that the ue terminal is unobstructed and that the ue system

is sealed correctly.

ALSO IF THE DHW FLOW RATE IS IN QUESTION :-

5. Check the DHW lter for blockage. Refer to Frame 70.

The cleaning procedures are covered more fully in Frames 40-45 and MUST be carried out in sequence.

IMPORTANT.

6. After completing the servicing or exchange of components always

test for gas tightness.

7. When work is complete the front panel MUST be correctly retted,

ensuring that a good seal is made.

GENERAL

Please Note: During routine servicing, and after any maintenance or change of part of the combustion circuit, the following must be checked:

- The integrity of the ue system and the ue seals,

- The integrity of the boiler combustion circuit and the relevant seals

- The operational (working) gas inlet pressure at maximum rate.

- The gas rate

- The combustion performance.

COMPETENCE TO CARRY OUT THE CHECK OF COMBUSTION PERFORMANCE

Please Note: BS 6798:2009 Specication for installation and maintenance of gas-red boilers of

rated input not exceeding 70kW net advises that:

- The person carrying out a combustion measurement should have been assessed as

competent in the use of a ue gas analyser and the

interpretation of the results.

- The ue gas analyser used should be one meeting

the requirements of BS7927 or BS-EN50379-3 and be calibrated in accordance with the analyser manufacturers requirements, and

- Competence can be demonstrated by satisfactory completion of the CPA1 ACS assessment, which covers the use of electronic portable combustion gas analysers in accordance with BS7967, Parts 1 to 4.

SERVICING

Do NOT OPERATE the boiler if the front panel is not

tted.

8. If, for any reason, the condensate trap/siphon has been removed

ensure the trap is relled with water before reassembling.

9. Check the gas consumption.

10. Check combustion by connecting the ue gas analyser to the ue

gas sampling point as shown in the diagram and measure CO &

If the CO/CO

complete ue system and combustion circuit seals have been veried and the inlet gas pressure (and gas rate) have been veried, then contact Keston.

11. Complete the service section in the Benchmark Commissioning Checklist.

Keston Combi - Installation and Servicing

ratio is greater than 0.004 AND the integrity of the

SERVICING

BOILER FRONT PANEL REMOVAL / REPLACEMENT

REMOVAL

1. Loosen the two screws retaining the front panel.

2. Pull the two spring clips down to disengage and pull panel

forward and upward and remove.

REPLACEMENT

3. Hook the panel onto the top retaining clips.

4. Push the panel until the 2 bottom spring clips engage

ensuring the 4 control knobs line up with the holes in the front panel.

5. Re-tighten the two retaining screws.

view from bottom of boiler

SERVICING

FAN AND VENTURI ASSEMBLY REMOVAL AND CLEANING

1. Disconnect the electrical leads from the fan.

2. Undo the gas pipe union connection to the

injector housing.

3. Remove the extended nut on the fan

mounting bracket.

4. Lift off fan and venturi assembly.

5. Inspect the injector for blockage or damage.

6. Inspect fan outlet sealing gasket and

replace if necessary.

Injector

view from top of boiler

Keston Combi - Installation and Servicing

3G9690

BURNER REMOVAL AND CLEANING

SERVICING

1. Ensure the sump is fully drained

2. Undo the two screws and remove the sump cover retaining the lower

ue manifold.

3. Lift the manifold to clear the bottom sealing gasket and remove

manifold.

4. Remove the 2 burner front xing screws and loosen the 2 rear

extended nuts by at least ten turns.

5. Lift off the burner from the combustion chamber. To facilitate the

removal angle the burner as shown.

IMPORTANT

The burner head is a ceramic plaque construction. Care must be taken to ensure that the burner is not placed down upon

its face as this may cause damage to the ceramic.

6. Brush off any deposits that may be on the ceramic with a

SOFT brush.

7. Inspect the sealing gasket around the burner for any

signs of damage. Replace as necessary.

CLEANING THE CONDENSATE TRAP/SIPHON

1. Pull off the rubber pipe at the sump drain.

2. Disconnect the condensate drain pipe.

3. Turn the siphon clockwise to disengage and lift to

remove.

Note. Keep siphon upright when removing

SERVICING

4. Clean siphon with water.

5. Re-assemble in reverse order.

B When re-assembling ensure the trap is full of water.

Keston Combi - Installation and Servicing

CLEANING THE HEAT EXCHANGER

SERVICING

Note: Ensure the condensate trap/siphon is fully drained before cleaning. Refer to

Frame 61.

1. Remove ignition and ame detection

electrodes. Refer to Frames 51 & 52.

2. It is advisable to replace the sump cover

prior to the water ush process.

3. Thoroughly ush the heat exchanger

by pouring water into the top of the combustion chamber ensuring the full top area is covered.

4. Remove the sump cover and clean loose deposits from the sump.

5. Inspect the ignition and detection electrodes. Ensure that they are clean and in good condition - replace if necessary.

6. Re-t the ignition and ame detection

electrodes, ensuring that both earth tabs

are tted to ignition electrode.

7. Check that the ignition and detection gaps are correct. Refer to Frames 51 & 52.

Ignition Electrode

Flame Detection

REASSEMBLY

SERVICING

Reassemble the boiler in the following order:

1. Ensure that the condensate trap/siphon is full of water.

2. Ret the burner ensuring the sealing gasket is correctly

positioned and free from damage (tighten the 4 xing screws

in the sequence shown below).

3. Ret the fan / venturi assembly ensuring the retaining tabs

are correctly positioned and the sealing gasket is correctly positioned and free from damage.

4. Reconnect the fan electrical leads.

5. Remove the sump cover and ret the lower ue manifold as

shown.

6. Ret the sump cover.

7. Ret the boiler front panel.

IMPORTANT. Ensure that the boiler front panel is

correctly tted and that a good seal is made.

8. Swing the control box back into its working position and secure.

9. Turn on the gas supply at the gas service cock.

10. Reconnect the electrical supply.

Keston Combi - Installation and Servicing

REPLACEMENT OF COMPONENTS

SERVICING

GENERAL

When replacing ANY component

1. Isolate the electricity supply.

2. Turn off the gas supply.

3. Remove the boiler front panel. Refer to Frame 39.

4. Release the retaining clip and swing the control box down

into its servicing position.

After replacing ANY component check operation of the boiler, including gas tightness, gas rate and combustion test.

IMPORTANT.

When work is complete, the front panel must be correctly

retted - ensuring that a good seal is made.

Notes.

1. In order to assist fault nding, the control panel has an LED diagnostic display. The key to boiler fault conditions is shown in Frame 75.

2. In order to replace components in Frames 61-72 it is necessary to drain the boiler. Refer to Frame 60.

THE BOILER MUST NOT BE OPERATED WITHOUT THE FRONT PANEL FITTED

FAN REPLACEMENT

1. Refer to Frame 45.

2. Disconnect the electrical leads from the fan.

3. Undo the gas pipe union connection to the

injector housing.

4. Remove the extended nut retaining the fan mounting bracket.

5. Lift and remove the fan and venturi assembly.

6. Remove the screw and twist venturi anti-

clockwise to remove venturi assembly, noting

the orientation of the venturi in relation to the fan body.

7. Transfer the venturi assembly to the new fan, replacing the ‘o’ ring if evidence of damage or deterioration is visible.

8. Fit the new fan / venturi assembly ensuring the retaining tabs are correctly positioned and the fan outlet sealing gasket is correctly positioned

and free from damage. Ret the extended nut.

9. Reassemble the boiler in reverse order, taking care not to overtighten the screw on the fan mounting bracket.

10. Check the operation of the boiler. Refer to Frame 36.

Retaining Tabs

SERVICING

Keston Combi - Installation and Servicing

BURNER INJECTOR REPLACEMENT

SERVICING

1. Refer to Frame 45.

2. Disconnect the electrical leads from the fan.

3. Undo the gas pipe union connection to the

injector housing.

4. Loosen the screw retaining the fan mounting bracket.

5. Lift and remove the fan and venturi assembly.

6. Remove the 2 injector housing screws.

7. Withdraw the injector housing.

8. Fit the new injector housing complete with

injector.

9. Reassemble in reverse order, ensuring that the new gas seal supplied is located correctly in the injector housing.

10. Check operation of the boiler. Refer to Frame 36.

SERVICING

BURNER REPLACEMENT

1. See Frame 39.

2. Refer to Frame 45.

3. Disconnect 2 ag terminals from the ue thermostat.

4. Undo the two screws and remove the sump cover.

5. Lift the manifold to clear the bottom sealing gasket and remove

manifold.

6. Remove the 2 front xing screws and loosen the 2 rear

extended nuts.

7. Lift off the burner from the combustion chamber. To facilitate the removal angle the burner as shown.

8. Fit the new burner, replacing any damaged or deteriorating sealing gasket.

9. Reassemble in reverse order. Refer to Frame 44.

10. Check the operation of the boiler. Refer to Frame 36.

Keston Combi - Installation and Servicing

SERVICING

RETURN THERMISTOR RENEWAL

1. Refer to Frame 44.

2. Unclip the return thermistor from the return pipe and withdraw it from the

boiler.

3. Disconnect the electrical lead from the thermistor.

4. Reconnect the electrical lead to the new thermistor and reassemble in

reverse order, ensuring that the thermistor is securely tted to the pipe on the

thermistor locator tabs as shown.

5. Check the operation of the boiler. Refer to Frames 29-35.

Thermistor Locator Tab

(with thermistor tted)

FLUE THERMOSTAT REPLACEMENT

1. Refer to Frame 45.

2. Undo the two screws and remove the

sump cover plate.

3. Disconnect the two ag terminals from the ue thermostat.

4. Lift the manifold to clear the bottom sealing gasket and remove manifold. .

5. Unscrew the two M3.5 screws that connect the thermostat to the manifold.

6. Replace thermostat with new part

and then ret the two screws, remembering to t rubber gasket and

sealing clamp.

SERVICING

Keston Combi - Installation and Servicing

Flue Thermostat

3mm

Straight edge

Spark Gap

3.5mm

12.5mm

Straight edge

IGNITION ELECTRODE REPLACEMENT

1. Refer to Frame 45.

2. Remove the burner. Refer to Frame 48.

3. Unplug the ignition lead from the electrode.

4. Remove the earth lead from the ignition

electrode.

5. Remove the 2 screws holding the ignition electrode to the combustion chamber.

6. Remove the electrode.

7. Fit the new ignition electrode, using the new

gasket supplied. Check dimensions as shown.

8. Reassemble in reverse order.

9. Check the operation of the boiler. Refer to

Frame 36.

SERVICING

Ignition Electrode

SERVICING

FLAME DETECTION ELECTRODE REPLACEMENT

1. Refer to Frame 45.

2. Remove the burner. Refer to Frame 48.

3. Unplug the ame detection lead from the

electrode.

4. Remove the 2 screws retaining the detection electrode.

5. Remove the electrode.

6. Fit the new ame detection electrode, using the

new gasket supplied.

7. Reassemble in reverse order.

8. Check the operation of the boiler. Refer to

Frame 36.

Flame Detection Electrode

Keston Combi - Installation and Servicing

SPARK GENERATOR REPLACEMENT

1. Refer to Frame 45.

2. Disconnect the leads from the spark

generator.

3. Remove the M5 screws securing the spark generator to the boiler chassis.

4. Fit the new spark generator and reassemble in reverse order ensuring the two earth leads are correctly replaced.

5. Check operation of the boiler. Refer to Frame 36.

SERVICING

Spark Generator

GAS CONTROL VALVE REPLACEMENT

1. Refer to Frame 45.

2. Unplug the electrical plug connection from the

gas control valve and disconnect the earth wire.

3. Undo the union nut on the outlet of the gas control valve.

4. Undo the gas inlet pipe union at the inlet to the gas control valve.

5. Loosen the back nut retaining the valve to the bracket and withdraw the valve forwards.

6. Fit the new gas control valve ensuring the two sealing washers are in place and reconnect gas and electrical connections.

7. Check operation of the boiler. Refer to Frame

36.

SERVICING

Keston Combi - Installation and Servicing

SERVICING

3G9690

DIVERTER VALVE ACTUATOR REPLACEMENT

1. Refer to Frame 45.

2. Remove the electrical plug.

3. Using a suitable tool pull out the retaining

clip and lift the diverter head from the brass body.

4. Fit new actuator head and reassemble in reverse order.

6. Check operation of the boiler. Refer to Frame 36.

Diverter Valve Actuator

SERVICING

CONDENSATE TRAP/SIPHON REPLACEMENT

1. Refer to Frame 45.

2. Pull off the rubber pipe at the sump drain.

3. Disconnect the condensate drain pipe.

4. Turn the siphon clockwise to disengage and lift to remove.

Note. Keep siphon upright when removing

5. Clean siphon with water.

6. Re-assemble in reverse order.

7. When re-assembling ensure the trap is full of water.

8. Check operation of the boiler. Refer to Frame 36.

Retaining Clip

Siphon

Keston Combi - Installation and Servicing

SERVICING

MAIN PCB REPLACEMENT

Note. Fit the earth strap provided with the PCB to your wrist and secure to a suitable earth on the boiler chassis.

1. Refer to Frame 45.

2. Note the control knob positions.

3. Remove the 2 screws retaining the control box cover.

4. Carefully lift the 4 retaining clips and remove control box

cover.

5. Unplug all lead connections to the PCB including the ribbon cable (to facilitate ribbon cable removal, ease side clips apart and pull upwards), also where applicable, push the small plastic clip with an electrical screwdriver to facilitate plug removal.

6. Spring out the two side retaining clips and pull the PCB upwards to clear the 4 corner retaining posts.

7. Take the new Primary PCB and attach the appropriate Boiler Chip Card (BCC).

Note. Ensure the correct orientation of BCC by placing

“TOP” side up as shown.

8. Re-connect all plug connections.

9. Reassemble in reverse order.

10. Turn power back on to the boiler, after a few moments the

display will start alternating between “c” and “0”. Turn the reset knob fully clockwise and when the display shows “ - ” turn the knob fully anti-clockwise IMMEDIATELY.

Finally move the knob into the required position (Standby,

Summer or Winter).

11. Check operation of the boiler. Refer to Frame 36.

Plastic

Clip

Ribbon Cable Connection

SERVICING

Keston Combi - Installation and Servicing

USER CONTROL PCB REPLACEMENT

Note. Fit the earth strap provided with the PCB

to your wrist and a suitable earth on the boiler chassis.

1. Refer to Frame 45.

2. Remove the main PCB, refer to Frame 57.

3. Unclip the PCB and lift to clear the mounting

posts.

4. Fit the new PCB ensuring the 4 potentiometer spindles line up with the control knobs which must be in a vertical position.

5. Reassemble in reverse order.

6. Check operation of the boiler. Refer to Frame

36.

SERVICING

PCB

Control Knobs (to be in vertical position)

DHW FLOW TURBINE SENSOR REPLACEMENT

Potentiometer spindle

1. Refer to Frame 45.

2. Remove condensate trap/siphon. Refer

to Frame 56.

3. Lift off the ow turbine sensor plastic

retaining clip.

4. Unplug the electrical connection and transfer to new turbine sensor.

5. Reassemble in reverse order.

6. Check operation of the boiler. Refer to

Frame 36.

Keston Combi - Installation and Servicing

SERVICING

3G9690

DRAINING THE BOILER

CENTRAL HEATING CIRCUIT

1. Refer to Frame 45.

2. Close all the CH water isolating valves on the boiler inlet.

3. To drain the primary heat exchanger circuit: Open the drain

valve and attach a length of hose to the CH drain point.

4. After replacing any component on the boiler, remove the hose, close the drain valve and open all system isolating valves (re-pressurise as appropriate by re-connecting the

lling loop, refer to Frame 22) before proceeding to check

operation of the boiler.

5. Disconnect lling loop. Refer to Frame 22.

6. Check operation of the boiler. Refer to Frames 36.

DOMESTIC HOT WATER CIRCUIT

1. Refer to Frame 45.

2. Close all the DHW water isolating valves on the boiler inlet.

3. To drain the domestic hot water circuit: As there is no direct

drain for the domestic hot water circuit, depending on the location of the boiler, opening the lowest hot water tap may drain this circuit. However it must be noted that some residual water will be experienced during replacement of components.

4. After replacing any component on the boiler, close tap, close

the drain valve and open all system isolating valves (re-

pressurise as appropriate by re-connecting the lling loop,

refer to Frame 22) before proceeding to check operation of the boiler.

5. Disconnect lling loop. Refer to Frame 22.

6. Check operation of the boiler. Refer to Frame 36.

PRESSURE GAUGE RENEWAL

1. Refer to Frame 45.

2. Drain the heating system. Refer to Frame

65.

3. Unscrew the pressure gauge and discard.

4. Fit new pressure gauge, using suitable

jointing compound.

5. Rell the boiler. Refer to Frame 22.

6. Check operation of the boiler. Refer to

Frame 36.

SERVICING

Keston Combi - Installation and Servicing

SAFETY RELIEF VALVE RENEWAL

SERVICING

1. Refer to Frame 45.

2. Drain the boiler. Refer to Frame 60.

3. Remove the condensate trap/siphon. Refer to

Frame 56.

4. Remove expansion vessel. Refer to Frame 73.

5. Disconnect the electrical connection from the

return thermistor.

6. Disconnect the 22mm pipe connection at the rear of the pump outlet.

7. Pull off the clip retaining the pipe to the heat exchanger swing the pipe to clear the pump and remove pipe.

8. Undo the safety valve union connection.

9. Withdraw the clip securing the safety valve.

10. Lift safety valve from boiler.

11. Fit the new safety valve and reassemble in

reverse order ensuring the new ‘o’ ring is tted to

the top of the return pipe.

12. Rell boiler. Refer to Frame 22. Check operation

of boiler. Refer to Frames 36.

SERVICING

PUMP AUTOMATIC AIR VENT REPLACEMENT

1. Refer to Frame 45.

2. Drain the boiler. Refer to frame 60.

3. Remove the expansion vessel. Refer to Frame 73.

4. Firstly, increase access area by disconnecting the

22mm pipe connection at top of pump chamber and bottom of heat exchanger and remove pipe Refer to Frame 62 (no’s 5,6 & 7).

5. The automatic air vent head is retained in the pump body with a bayonet connection. The air vent head and

oat assembly is removed by turning the head anti-

clockwise (viewed from above) and pulling upwards.

6. Reassembly is the reverse of the above. Ensure the air

vent head ‘o’ ring seal is in place when retting and the new ‘o’ ring is tted to the return pipe top connection.

7. Ensure the air vent cap is loose.

8. Rell the boiler. Refer to Frame 22. Check for leaks

around the new air vent joint.

9. Check the operation of the boiler. Refer to Frame 36.

Keston Combi - Installation and Servicing

SERVICING

DHW FLOW TURBINE CARTRIDGE REPLACEMENT

1. Refer to Frame 45.

2. Drain the boiler. Refer to Frame 60.

3. Remove condensate trap/siphon. Refer to

Frame 56.

4. Remove the DHW ow turbine sensor. Refer to

Frame 59.

5. Unscrew the top connection to access the internal part.

6. Fit the new turbine cartridge.

7. Ret the turbine ow sensor

8. Reassemble in reverse order.

9. Rell the boiler. Refer to Frame 22.

10. Check operation of the boiler. Refer to

Frames 36.

DIVERTER VALVE INTERNAL CARTRIDGE REPLACEMENT

FRONT CARTRIDGE REPLACEMENT

1. Refer to Frame 45.

2. Drain the boiler. Refer to Frame 65.

3. Remove the diverter valve head. Refer

to Frame 55.

4. Unscrew the top connection to access the internal cartridge.

5. Fit the new valve mechanism ensuring

the correct t of the pin.

6. Reassemble in reverse order.

7. Rell the boiler. Refer to Frame 22.

8. Check operation of the boiler. Refer to

Frame 36.

FRONT CARTRIDGE REAR CARTRIDGE

REAR CARTRIDGE REPLACEMENT

1. Refer to Frame 45.

2. Drain the boiler. Refer to Frame 60.

3. Remove the diverter valve head. Refer to Frame 55.

4. Remove the ow pipe. Refer to Frame 22 no. 12.

5. Disconnect the CH ow pipe and DHW outlet pipe union connections underneath

the boiler. Refer to Frame 60.

6. Remove the plate heat exchanger LH xing screw. Refer to Frame 66.

7. Remove the screw retaining the brass block to the bottom of the boiler casing

and lift the brass block clear of the boiler.

8. Unscrew the rear cartridge connection.

9. Fit the new valve mechanism ensuring the correct t of the pin.

10. Reassemble in reverse order.

11. Rell the boiler. Refer to Frame 22.

12. Check operation of the boiler. Refer to

Frame 36.

SERVICING

Keston Combi - Installation and Servicing

9 8

SERVICING

DHW PLATE HEAT EXCHANGER REPLACEMENT

1. Refer to Frame 45.

2. Drain the boiler. Refer to Frame 60.

3. Remove condensate trap/siphon. Refer to Frame 56.

4. Remove the diverter valve actuator. Refer to Frame 55.

5. Remove the 2 allen screws securing the plate heat

exchanger to the brass housings.

6. Manoeuvre the plate heat exchanger out of the top LH or centre of the controls area.

7. Fit the new plate heat exchanger, using the new o-rings supplied.

Note. The mounting pins are offset so the correct position

can be dened from the location of the holes on the brass mounting.

8. Reassemble in reverse order.

9. Rell the boiler. Refer to Frame 22.

10. Check operation of the boiler. Refer to Frame 36.

SERVICING

PUMP HEAD REPLACEMENT

1. Refer to Frame 45.

2. Drain the boiler. Refer to Frame 60.

3. Disconnect the electrical plug from the

pump.

4. Remove the 4 Allen screws retaining the pump head.

5. Remove the pump head.

6. Fit the new pump head.

7. Reassemble in reverse order.

8. Rell the boiler. Refer to Frame 22.

9. Check operation of the boiler. Refer to

Frame 36.

Keston Combi - Installation and Servicing

SERVICING

CH WATER PRESSURE SENSOR REPLACEMENT

1. Refer to Frame 45.

2. Drain the boiler. Refer to Frame 60.

3. Remove condensate trap/siphon. Refer to

Frame 56.

4. Using a suitable tool pull out the retaining clip.

5. Pull the pressure sensor upwards to remove.

6. Unplug the electrical connection and transfer to

the new pressure sensor.

7. Push the new pressure sensor onto the rear

pump housing and t retaining clip.

8. Reassemble in reverse order.

9. Rell the boiler. Refer to Frame 22.

10. Check Operation of the boiler. Refer to Frame

36.

DHW FILTER CLEANING / REPLACEMENT

1. Refer to Frame 45.

2. Isolate the mains cold water supply to the

boiler.

3. Drain the boiler DHW circuit. Refer to Frame 60.

4. Remove the DHW ow turbine cartridge.

Refer to Frame 64.

5. Unscrew the ow regulator housing.

6. Remove the lter.

7. Clean or replace lter as necessary.

8. Reassemble in reverse order.

9. Rell the boiler. Refer to Frame 22.

10. Check Operation of the boiler. Refer to

Frame 36.

SERVICING

Keston Combi - Installation and Servicing

SERVICING

DHW FLOW REGULATOR CLEANING / REPLACEMENT

1. Refer to Frame 45.

2. Isolate the mains cold water supply to the

boiler.

3. Drain the boiler DHW circuit. Refer to Frame

60.

4. Remove the DHW ow turbine cartridge.

Refer to Frame 69.

5. Unscrew the ow regulator housing.

6. Inspect the ow regulator for any blockage

and remove if necessary.

7. Reassemble in reverse order.

8. Rell the boiler. Refer to Frame 22.

9. Check Operation of the boiler. Refer to

Frame 36.

SERVICING

NO FLOW THERMISTOR REPLACEMENT

1. Refer to Frame 45.

2. Drain down the boiler. Refer to Frame 60.

3. Unplug the electrical lead.

4. Unscrew the thermistor (to facilitate removal a

13mm socket spanner should be used).

5. Fit the new thermistor using the sealing washer provided.

6. Reassemble in the reverse order.

7. Rell the boiler. Refer to Frame 22.

8. Check the operation of the boiler. Refer to Frame

36.

Keston Combi - Installation and Servicing

SERVICING

HEAT ENGINE RENEWAL

Refer also to Frame 6 - ‘Boiler Exploded View’

IMPORTANT

Before starting the removal procedure, protect the gas and electrical controls with a waterproof sheet or plastic bag.

1. Refer to Frame 45.

2. Drain the boiler. Refer to Frame 60.

3. Remove the fan / venturi assembly and place on one side.

Refer to frame 46.

4. Remove the burner and place on one side. Refer to Frame

48.

5. Remove the ignition and detection electrodes and diverter actuator head. Refer to Frames 51, 52 and 55.

6. Remove the spark generator. Refer to Frame 53.

7. Disconnect ue thermostat.

8. Remove the gas valve. Refer to Frame 54.

9. Remove the expansion vessel. Refer to Frame 73.

10. Remove the no ow thermistor. Refer to Frame 71.

11. Remove the 2 M5 screws retaining the gas valve mounting

bracket and transfer bracket to the new heat exchanger.

12. Undo the inlet pipe union nut and remove the retaining spring clip and remove pipe.

13. Undo the ow pipe union nut and remove pipe.

14. Remove the condensate rubber pipe. Refer to Frame 56, no. 2.

15. Remove the two heat exchanger xing screws.

16. Remove the Heat exchanger.

17. Reassemble in reverse order, ensuring the heat exchanger

LH retaining bracket is correctly positioned. Replace any new ‘o’ rings supplied with new heat exchanger and replacing gaskets or seals if any sign of damage is evident. When

replacing the spring clips located on both the ow and return

pipe connections, ensure clip is oriented to correctly match connecting pipe diameters.

18. Ensure the trap/siphon is lled with water. Refer to Frame 56.

19. Rell the boiler. Refer to Frame 22.

20. Check operation of the boiler. Refer to Frame 36.

SERVICING

Keston Combi - Installation and Servicing

SERVICING

EXPANSION VESSEL RECHARGING & REPLACEMENT

RECHARGING

1. Refer to Frame 45.

2. Remove the charge point cover.

3. Recharge the tank pressure to 0.75 bar.

4. Re-assemble in reverse order

5. Check operation of the boiler. Refer to Frame36.

REPLACEMENT

6. Refer to Frame 45.

7. Drain the boiler CH circuit. Refer to Frame 60.

8. Unscrew the union nut on the vessel water

connection pipe.

9. Support the expansion vessel and unscrew the 2 screws from the securing clamp, located on the top of the boiler, and remove. (Note the position of the bracket on the vessel)

10. Remove the expansion vessel.

11. Fit the new expansion vessel.

12. Reassemble in reverse order.

13. Rell the boiler. Refer to Frame 22.

14. Check operation of the boiler. Refer to Frame 36.

Recharge Point

SERVICING

BOILER SEALING PANEL SEAL REPLACEMENT

1. Refer to Frame 45.

2. Remove the old seal from the casing and

thoroughly clean the casing surfaces.

3. Fit the new seal, ensuring the bottom joint provides an air tight seal.

5. Reassemble in reverse order.

6. Check operation of the boiler. Refer to

Frame 36.

Note. Ensure that the boiler front panel is

correctly sealed, compressing the seal to make an airtight joint.

Keston Combi - Installation and Servicing

Fault Finding

Overheat lockout 1 Fill system to 1.0 bar 2 Bleed radiators

3 Check radiator valves open

4 Reset boiler 5 Contact installer

Go to Frame 76

Flow Temperature Overheat Lockout

Ignition lockout /

Flue Overheat

1 Check other gas appliances work

2 Reset boiler

3 Contact Installer

Go to Frame 77 Ignition Lockout

Low water pressure 1 Fill system to 1.0 bar

Go to Frame 79

Low Water Pressure

2 Bleed radiators

Flame loss 1 Check other gas appliances

Go to Frame 80

Flame Loss

2 contact installer

Too many resets Contact installer

5 Resets with 15 minutes

Turn power off and on

Fault 8 Contact installer

3 Contact installer

Go to Frame 78

False Flame Lockout

Fan fault Contact installer

Go to Frame 81

Fan Fault

Return thermistor fault Contact installer

Go to Frame 82

Return Thermistor Fault

Outside sensor fault Contact installer

Go to Frame 83

Outside sensor fault

Low mains voltage Contact electricity provider

Low mains voltage

Contact Electricity Provider

PCB Fault Contact installer

If PCB is a spare check Boiler Chip Card

(BCC) fitted otherwise replace PCB

PCB Replaced Reset boiler

Reset the boiler

Flow thermistor fault Contact installer

Go to Frame 82

Return Thermistor Fault

Boiler Chip Card Fault Contact installer

Go to Frame 85

BCC Fault

Go to Frame 86

No CH operation but DHW works OK

No CH operation but DHW operates OK

Go to Frame 87

No DHW but CH operates OK

No DHW operation but CH operates OK

No Display

Go to Frame 88

No Display

12 month service interval request

Contact installer

It is recommended to have the boiler serviced

Reset the boiler to clear message

FAULT FINDING CHART MAIN MENU

Note. Boiler status display information is shown in shaded boxes below. Up to six messages will be displayed in rotation.

RESET PROCEDURE - To reset boiler, turn mode knob to reset position and immediately turn knob back to required setting.

Keston Combi - Installation and Servicing

Fault Finding Fault Finding Fault Finding Fault Finding Fault Finding

Fault Finding

OVERHEAT LOCKOUT - 1 FILL SYSTEM TO 1.0 BAR - 2 BLEED RADIATORS -

3 CHECK RADIATOR VALVES OPEN - 4 RESET BOILER - 5 CONTACT INSTALLER

Is the Boiler and CH System lled with water and all

isolation and radiator valves open?

YES

Is the Flow/Return Differential across the Boiler in excess of 30°C?

Check the Return Thermistor (Refer to Frame 49)

Check resistance using a suitable multimeter

connected across the thermistor’s terminal pins

At 25

At 60

At 85

C expect 9,700 - 10,300 Ohms

C expect 2,400 - 2,600 Ohms

C expect 1,000 - 1,100 Ohms

IGNITION LOCKOUT / FLUE OVERHEAT - 1 CHECK OTHER GAS APPLIANCES WORK

YES

RESET PROCEDURE - To reset boiler, turn mode knob to reset position and immediately turn knob back to required setting.

Fill and vent the system and open all isolation valves, then reset boiler

Check that the Pump is rotating freely. Is the Differential now below 20°C?

Replace the Pump, then reset boiler

YES

OK, now

reset boiler

- 2 RESET BOILER - 3 CONTACT INSTALLER

If the boiler is reset does the boiler ignite for a short time and then extinguish?

YES

Is the Gas Pressure available at the Boiler Inlet (>18 mbar)?

YES

Check gas supply and rectify fault

Check the detection electrode and associated harness for: continuity, visual condition and position (Refer to Frame 52). Check if the condensate pipe is blocked. Replace as necessary

Check ignition electrode and associated harness for: continuity, visual condition and position. (Refer to Frame 51) Are these functioning correctly?

Fault Finding Fault Finding Fault Finding Fault Finding Fault Finding

YES

Check siphon and condensate drain pipe work for blockage and rectify if necessary. Boiler now working OK?

Check ue for obstruction

Check wiring to thermostat

Check ue temperature always

remains below 90ºC

Check if burner is damaged

Replace heat exchanger

YES

Is approx 215Vdc supply available at the Gas Valve? (* See note)

YES

Unplug gas valve. Is resistance between outside pins 4KΩ (±2)?

YES

Check spark generator and associated harness for: continuity and visual condition. (Refer to Frame 53) Are these functioning correctly?

Replace Ignition Electrode and associated harness as necessary

Clear obstruction

Ensure wiring correctly

connected

Replace Thermostat

Replace burner

Check wiring connection from gas valve to PCB for continuity. If the wiring is OK then replace the PCB

Replace Gas Valve

Replace Spark Generator and harness as necessary

* Note: due to the wave form of the rectied voltage, the reading will vary depending on the type of meter used to measure the value. In general terms a reading greater than 150V indicates that the correct voltage is supplied to the gas valve.

RESET PROCEDURE - To reset boiler, turn mode knob to reset position and immediately turn knob back to required setting.

Keston Combi - Installation and Servicing

Fault Finding

FAULT 8 - CONTACT INSTALLER (FALSE FLAME LOCKOUT)

Reset the boiler, does Boiler Work OK?

Separate the ame detection electrode in-line

connector. Is there continuity between the terminals pins connected to the electrode?

Check routing and integrity of internal boiler wiring.

RESET PROCEDURE - To reset boiler, turn mode knob to reset position and immediately turn knob back to required setting.

YES

Check routing and integrity of internal boiler wiring is OK. Check condition of Flame Sense Electrode and replace if deteriorated.

Replace Flame Detection Electrode

LOW WATER PRESSURE - 1 FILL SYSTEM TO 1.0 BAR - 2 BLEED RADIATORS -

3 CONTACT INSTALLER

Are the Boiler and CH System lled with water and

all isolation and radiator valves open (check pressure gauge is between 1 to 1.5 bar)?

YES

Are connections on water pressure sensor secure?

YES

Replace water pressure sensor

Fill and vent the system and open all isolation valves

Re-t connections

Keston Combi - Installation and Servicing

Fault Finding Fault Finding Fault Finding Fault Finding Fault Finding

Fault Finding

FLAME LOSS - 1 CHECK OTHER GAS APPLIANCES WORK -

2 CONTACT INSTALLER

Does the boiler ignite for a short time and then extinguish?

YES

Check the detection electrode and associated harness for: continuity, visual condition and position (Refer to Frame 52). Check if condensate

pipe is blocked. Check if ue is

blocked. Replace as necessary

Is the Gas Pressure available at the Boiler Inlet (18 mbar)?

YES

Is 215Vdc supply available at the

Gas Valve while the ame is on?

(* See note)

YES

Check spark generator and associated harness for: continuity and visual condition. (Refer to Frame 53) Are these functioning correctly?

YES

Check ignition electrode and associated harness for: continuity, visual condition and position. (Refer to Frame 51) Are these functioning correctly?

Check gas supply and rectify fault

Check wiring from gas valve to PCB for continuity. If the wiring is OK then replace the PCB

Replace Spark Generator and Harness as necessary.

Replace Ignition Electrode and associated harness as necessary

YES

Check siphon and condensate drain pipe work for blockage and rectify if necessary. Boiler now working OK?

Check ue for obstruction

Check wiring to thermostat

Check ue temperature always

remains below 90ºC

Check if burner is

damaged

YES

Replace Gas Valve

Clear obstruction

Ensure wiring correctly

connected

Replace Thermostat

Replace burner

Replace heat exchanger

Fault Finding Fault Finding Fault Finding Fault Finding Fault Finding

Keston Combi - Installation and Servicing

Fault Finding

FAN FAULT - CONTACT INSTALLER

Does the wiring from the Fan to the PCB have secure connections at both ends and has not deteriorated? Does the wiring have continuity?

YES

Is there 230Vac at the Blue and Brown connections to the 3 way connection on the Fan?

RETURN THERMISTOR FAULT - CONTACT INSTALLER

Remove the Return Thermistor from the CH Return

Pipe and disconnect the wires.

Check the resistance using a suitable multimeter

connected across the thermistor’s terminal pins.

At 25

At 60

At 85

C expect 9,700 - 10,300 Ohms

C expect 2,400 - 2,600 Ohms

C expect 1,000 - 1,100 Ohms

Is the Thermistor value correct?

YES

Rectify Wiring & connections

Replace PCB

Replace Fan

Fit a new Thermistor

Check and replace wiring as necessary

Is there continuity between the PCB and the Thermistor?

YES

OUTSIDE SENSOR FAULT - CONTACT INSTALLER

Is the wiring securely connected at both the boiler and Outside Sensor?

YES

Disconnect the wires to the outside sensor.

Check the resistance using a suitable multimeter

connected across the Outside Sensor’s terminal pins.

C expect 31,000 - 35,000 Ohms

At 0

At 15

At 30

C expect 15,000 - 16,500 Ohms

C expect 7,700 - 8,500 Ohms

Is the Outside Sensor value correct?

YES

Replace PCB

Securely connect the wiring at both the boiler and Outside Sensor

Fit a new Outside Sensor

Securely connect the wiring at the Terminal Block and the PCB

Is the wiring securely connected between the incoming terminal block boiler connection of the Outside Sensor and the PCB?

Keston Combi - Installation and Servicing

YES

Replace PCB

Fault Finding Fault Finding Fault Finding Fault Finding Fault Finding

Fault Finding

FLOW THERMISTOR FAULT - CONTACT INSTALLER

Is the wiring securely connected to the Flow Thermistor (located in the top of the Heat Exchanger?)

YES

Disconnect the wiring from the Flow Thermistor

Check the resistance using a suitable multimeter connected

across the Thermistor’s terminal pins.

At 25

At 60

At 85

C expect 9,700 - 10,300 Ohms

C expect 2,400 - 2,600 Ohms

C expect 1,000 - 1,100 Ohms

Is the Thermistor value correct?

BOILER CHIP CARD FAULT - CONTACT INSTALLER

Is the correct BCC for the boiler securely inserted into the slot at the front left of the PCB?

(identied by the label on the BCC)

YES

Replace the BCC with a new BCC (that is correct for the boiler). After switching power on and ‘c0’ being shown, reset the boiler. Is ‘c2’ still shown?

YES

Securely connect the wiring to the Flow Thermistor

Fit a new Thermistor

Is the wiring securely connected to the low voltage 6 way connector at the front left hand side of the PCB?

YES NO

Replace PCB

Securely attach the BCC for the boiler onto the PCB and after switching power on and ‘c0’ being shown, reset the boiler.

Note. Ensure the correct orientation of BCC by placing “TOP” side up.

Replace PCB

Securely connect the wiring to the PCB

RESET PROCEDURE - To reset boiler, turn mode knob to reset position and immediately turn knob back to required setting.

NO CH OPERATION BUT DHW WORKS OK

Is the mode knob in the Winter position?

YES

Are the Timer and the Room Thermostat switched on?

YES

Are the Radiator Valves Open?

YES

Is there 230Vac at (A)?

YES NO

Replace the

Diverter Valve

There is no Voltage from the Timer/Room Stat. This is not boiler fault. Ensure Voltage is supplied to boiler by rectifying external wiring.

Move the mode knob to the Winter position

Switch the Timer and Room Thermostat On

Open the Radiator Valves

Fault Finding Fault Finding Fault Finding Fault Finding Fault Finding

Keston Combi - Installation and Servicing

NO HW BUT CH ON

Fault Finding

Does the display show “hot water” “temperature XXºC” - “high efciency”?

YES

Are the ow rates correct as per Frame 2.

YES

Is the wiring between the PCB and the diverter valve motor connected?

YES

Check diverter head fully engaged and clip secured onto waterset.

YES

Is diverter stuck in the CH position

YES

Check and replace diverter valve motor head. Is Boiler DHW OK?

Is the red neon illuminated on the turbine sensor?

Adjust ow rates to achieve 35º temp rise and check lter tted in

turbine is not blocked with debris.

Reconnect wiring or replace wiring harness if no continuity.

Re-engage diverter head and secure clip to wateset

Replace PCB

YES

Is hot and cold pipework crossed?

Replace PCB

Is the wiring connected between PCB and DHW sensor?

Remove the turbine, and check for debris in the

turbine & lter. Replace

turbine if necessary. Is DHW OK?

Replace turbine sensor

YES

Change diverter Valve cartridge - rear section

NO DISPLAY

Is there 230Vac to the boiler at L and N?

YES

Is the wiring from the terminal block to the Main PCB connected securely?

YES

Is the ribbon cable from the main PCB to the User Interface PCB connected securely?

YES

Is ribbon cable damaged?

YES

Replace the User Interface PCB

Re-connect wiring

Supply power to the boiler

Connect the wiring from the terminal block to the Main PCB securely.

Connect the ribbon from the main PCB to the User Interface PCB securely

Replace ribbon cable

Keston Combi - Installation and Servicing

Fault Finding Fault Finding Fault Finding Fault Finding Fault Finding

SPARE PARtS

When replacing any part on this appliance use only spare parts that you can be assured conform to the safety and performance

specication that we require. Do not use reconditioned or copy parts that have not been clearly authorised by Keston. Failure to do so

could affect safety or performance of this appliance.

Our Parts team are also available to help with your Keston Spare Parts enquiries on 01482 498665.

When calling, and to ensure we can provide you with the most accurate parts information, please ensure you have the following to hand;

- Boiler Model

- Appliance GC Number

- Boiler Serial Number

Keston Combi - Installation and Servicing

65Keston Combi - Installation and Servicing

Benchmark Commissioning and Servicing Section

It is a requirement that the boiler is installed and commissioned to the manufacturers instructions and the data fields on the commissioning checklist completed in full.

To instigate the boiler guarantee the boiler needs to be registered with the manufacturer within one month of the installation.

To maintain the boiler guarantee it is essential that the boiler is serviced annually by a Gas Safe registered engineer who has been trained on the boiler installed. The service details should be recorded on the Benchmark Service Interval Record and left with the householder.

www.centralheating.co.uk

GAS BOILER SYSTEM COMMISSIONING CHECKLIST

This Commissioning Checklist is to be completed in full by the competent person who commissioned the boiler as a means of demonstrating compliance with the appropriate Building Regulations and then handed to the customer to keep for future reference.

CONTROLS

Programmable room thermostat

Optimum start control

Combination Boiler

Fitted

Automatic bypass to system Fitted

Boiler interlock

ALL SYSTEMS

Yes

CENTRAL HEATING MODE

Central heating return temperature

COMBINATION BOILERS ONLY

DOMESTIC HOT WATER MODE

Cold water inlet temperature

CONDENSING BOILERS ONLY

ALL INSTALLATIONS

Yes

mbar OR mbar

Yes

mbar OR mbar

Yes Temperature

Yes

AND

Ratio

Yes

* All installations in England and Wales must be to Local Authority Building Control (LABC) either directly or through a

Competent Persons Scheme. A Building Regulations Compliance

will then be issued to the customer.

www.centralheating.co.uk

SERVICE RECORD

It is recommended that your heating system is serviced regularly and that the appropriate Service Interval Record is completed.

Service Provider

SERVICE 01

(Where Possible) AND

Signature

SERVICE 03

(Where Possible) AND

Signature

SERVICE 05

AND

SERVICE 02

Signature

(Where Possible) AND

AND

SERVICE 04

Signature

(Where Possible) AND

AND

SERVICE 06

(Where Possible) AND

Signature

SERVICE 07

(Where Possible) AND

Signature

SERVICE 09

(Where Possible) AND

AND

Signature

(Where Possible) AND

AND

SERVICE 08

Signature

(Where Possible) AND

AND

SERVICE 10

(Where Possible) AND

AND

Signature

* All installations in England and Wales must be to Local Authority Building Control (LABC) either directly or through a

Competent Persons Scheme. A Building Regulations Compliance

Signature

will then be issued to the customer.

FLOWCHART FOR CO LEVEL AND COMBUSTION RATIO

CHECK ON COMMISSIONING A CONDENSING BOILER

Important Preliminary Information on Checks

The air gas ratio valve is factory-set and must not be adjusted DURING COMMISSIONING.

If the boiler requires conversion to operate with a different gas family (e.g. conversion from natural gas to LPG) separate guidance is provided with the conversion kit supplied and this must be followed.

PRIOR TO CO LEVEL AND COMBUSTION RATIO CHECK

The installation instructions must have been followed, gas type verified and gas supply pressure / gas rate checked as required prior to commissioning.

As part of the installation process, ESPECIALLY WHERE A FLUE HAS BEEN FITTED BY PERSONS OTHER THAN THE BOILER INSTALLER, visually check the integrity of the whole flue system to confirm that all components are correctly assembled, fixed and supported. Check that maximum flue lengths have not been exceeded and all guidance has been followed (e.g. Gas Safe Register Technical Bulletin (TB) 008 where chimney/flues are in voids).

The ECGA should be of the correct type, as specified by BS 7967.

Prior to its use, the ECGA should have been maintained and calibrated as specified by the manufacturer. The installer must have the relevant competence for use of the analyser.

Check and zero the analyser IN FRESH AIR in accordance with the analyser manufacturer’s instructions.

KEY:

CO = carbon monoxide

= carbon dioxide

O2 = oxygen

Combustion Ratio = The CO reading measured in ppm divided by the CO2 reading first converted to ppm

ppm = parts per million

GS(I&U)R = Gas Safety (Installation and Use) Regulations

*Setting to Minimum Rate:

1. Turn the CH temperature control knob into the 10 O’clock position.

2. Create a CH demand by ensuring that the system controls are requesting heat and the boiler Mode Knob is in the Winter Position.

3. Within an overall time of 3 seconds, turn the CH temperature control knob fully clockwise, back to 10 O’clock and then fully clockwise again.

4. The following messages will be shown in rotation on the display:

“Service Mode” “Minimum Output” “Move CH Knob to End”

and the boiler output will be reduced to minimum.

5. The boiler will remain at minimum rate for 5 minutes before reverting to normal operation.

Keston Combi -

Installation and Servicing

Start

Set Boiler to Maximum Gas Rate

In accordance with boiler instructions,

Insert analyser probe into air inlet test point (where available) and allow

Carry Out Flue Integrity Check Using Analyser

set boiler to operate at maximum rate

(full load condition). Allow sufficient

time for combustion to stabilise.

Note. Do not insert analyser probe during this period to avoid possible

flooding of sensor.

Note. Where no air inlet test point is provided then a flue integrity check with the analyser is not possible. The installer should verify that flue integrity has

been visually checked in accordance with the “Prior to CO level and

combustion ratio check” (see opposite page) before proceeding to the

“check CO level and combustion ratio at maximum rate” stage below.

Verify Flue Integrity

Analyser readings indicate that combustion products and inlet air

must be mixing. Further investigation of the flue is therefore required.

Check that flue components are assembled, fixed and supported as

per instructions. Check that flue and flue terminal are not obstructed.

2 more than or

equal to 20.6% OR CO

Yes

less than or equal to

0.2%?

readings to stabilise.

O2 more than or

equal to 20.6% OR CO

less than or equal to

0.2%?

Yes

Check CO level and Combustion Ratio

at Maximum Gas Rate

With boiler still set at maximum gas rate,

insert analyser probe into flue gas

sampling point. Allow readings to stabilise

before recording.

Turn off appliance and call Ideal Technical Helpline for advice

The appliance must not be commissioned until problems are identified

and resolved. If commissioning cannot be fully completed, the appliance

must be disconnected from the gas supply in accordance with GSIUR.

Check that no seals, e.g. Those on flue extensions, have

been displaced during installation. Rectify if necessary.

CO level less

than 350ppm AND CO/CO

Yes

In accordance with boiler instructions, set boiler to

operate at minimum rate (to minimum load condition).

ratio less than

0.0040?

Check CO and Combustion Ratio at Minimum Gas Rate

With boiler set at minimum rate, insert analyser probe into flue

gas sampling point. Allow readings to stabilise before recording.

Turn off Appliance and Call Ideal Technical Helpline

The appliance must not be commissioned until problems

are identified and resolved. If commissioning cannot be

fully completed, the appliance must be disconnected from

the gas supply in accordance with GS(I&U)R. NOTE:

Check and record CO level and combustion ratio at both

maximum AND minimum rate before contacting Ideal.

CO level less

than 350ppm AND CO/CO

ratio less than

0.0040?

Yes

Set Boiler to Minimum Gas Rate

(*see opposite page)

Allow sufficient time for combustion to stabilise.

CO level less

than 350ppm AND CO/CO

ratio less than

0.0040?

Yes

Boiler is Operating Satisfactorily

No further actions required.

Ensure test points are capped, boiler case is correctly replaced and all other commissioning procedures are completed. Complete Benchmark

Checklist, recording CO and combustion ratio readings as required.

71Keston Combi - Installation and Servicing

Keston Heating, PO Box 103, National Avenue, Kingston Upon Hull, HU5 4JN Tel. +44 (0) 1482 443005 Fax. +44 (0) 1482 467133. www.keston.co.uk

Keston pursues a policy of continuing improvement in the design and performance of its products.

The right is therefore reserved to vary specication without notice.

February 2014 UIN 207895 A03

Keston Combi 30kw, Combi 35kw User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual