Baxi Bermuda Inset 2 Boiler 50/4 Datasheet

Please leave these instructions with the user
Baxi Bermuda
Inset 2 Boiler 50/4
Fireside Gas Central Heating Unit
Comp N° 238983 - Issue 4 - 10/99
Installation and
Servicing Instructions

2
Page 2
Natural Gas
Baxi Bermuda Inset 2 Boiler 50/4
G.C. No. 44 075 01
For use with the following firefronts:
Baxi Bermuda Inset 2 TS
G.C. No. 37 075 12
Baxi Bermuda Inset 2 BS
G.C. No. 37 075 13
Baxi Bermuda Inset 2 FS
G.C. No. 37 075 15
Baxi Bermuda Inset 2 KS
G.C. No. 37 075 14
Baxi Bermuda Inset 2 TS Deluxe
G.C. No. 37 075 28
Baxi Bermuda Inset 2 BS Deluxe
G.C. No. 37 075 29
Baxi Bermuda Inset 2 FS Deluxe
G.C. No. 37 075 30
Baxi Bermuda Inset 2 KS Delux
G.C. No. 37 075 31
Baxi Limited is one of the leading manufacturers of domestic
heating products in the UK.
Our first priority is to give a high quality service to our
customers. Quality is built into every Baxi product - products
which fulfil the demands and needs of customers, offering
choice, efficiency and reliability.
To keep ahead of changing trends, we have made a
commitment to develop new ideas using the latest
technology - with the aim of continuing to make the products
that customers want to buy.
Baxi is also the largest manufacturing partnership in the
country. Everyone who works at the company has a
commitment to quality because, as shareholders, we know
that satisfied customers mean continued success.
We hope you get a satisfactory service from Baxi. If not,
please let us know.
Baxi is a BS-EN ISO 9001
Accredited Company

3
Contents - Page 3
Section
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
Introduction
Technical Data
System Details
Water Circulating Systems
Treatment of Water Circulating Systems
Pipework
System Controls
Fully Pumped System
Overheat Kit & Sealed Systems
Storage Systems
Pumped Heating & Gravity Hot Water
Site Requirements
Builders Opening
Location
Fireplace Opening & Surround
Frame Extension Kit
Flue
Ventilation
Gas Supply
Electrical Supply
Installation
Initial Preparation
Right Hand Water Connections
Connecting the Sensing Pipe
Siting the Boiler
Securing the Boiler
Water Connections
Fully Pumped Systems
Overheat Thermostat
Pumped Heating & Gravity Hot Water
Gas Connection
Electrical Connection
Making the Electrical Connection
Overheat Thermostat
Flue Connection
Completion
CommissionIng the Appliance
Annual ServicIng
Annual Servicing
Removal of Firefront
Removal of Controls
Cleaning the Lint Arrestor
Cleaning the Burner & Main Injector
Cleaning the Pilot/A.S.D. Assembly
Cleaning the Heat Exchanger
Changing Components
Changing Components
Removal of Firefront
Lint Arrestor
Suppression Capacitor
Thermostat
Piezo Igniter Unit
Removal of Controls
Gas Valve
Burner & Main Injector
Pilot/A.S.D. Assembly
Ignition Lead
Fault Finding
Short Parts List
Page
4
5
6
9
12
18
19
22
26
28

4
1.0 Introduction - Page 4
The boiler meets requirements of Statutory Instrument
“The Boiler (Efficiency) Regulations 1993 N° 3083” and
is deemed to meet the requirements of Directive
92/42/EEC on the efficiency requirements for new hot
water boilers fired with liquid or gaseous fuels.
Type test for purpose of Regulation 5 certified by:
Notified Body 0086.
Product/production certified by: Notified Body 0086.
“Benchmark” Log Book
As part of the industry-wide “Benchmark” initiative all
Baxi boilers now include an Installation, Commissioning
and Service Record Log Book. Please read the Log
Book carefully and complete all sections relevant to the
appliance and installation. These include sections on
the type of controls employed, flushing the system,
burner operating pressure etc. The details of the Log
Book will be required in the event of any warranty work.
Also, there is a section to be completed at each
subsequent regular service visit.
1.1 Description
1. The Baxi Bermuda Inset 2 is a combined central heating
boiler and gas fire designed for installation within a builders
opening in the living space of a dwelling.
2. The firefront is intended for hearth mounting.
3. These instructions relate to the central heating boiler
section of the appliance (Fig. 1).
4. The boiler is range rated, with outputs as shown:
5. The appliance is preset at its MIDRANGE heat input rate
and is designed for use on NATURAL GAS only. The boiler
is suitable for fully pumped and pumped central heating with
gravity hot water systems.
6. Sealed System applications require an optional overheat
thermostat kit.
1.2 Installation
1. The appliance is suitable for installation only in G.B. and
I.E. and should be installed in accordance with the rules in
force. For Ireland install in accordance with l.S. 813
“Installation of Gas Appliances”.
2. The installation must be carried out by a CORGI
Registered Installer or other competent person and be in
accordance with the relevant requirements of Gas Safety
(Installation and Use) Regulations, the Building Regulations
(Scotland) (Consolidation), the Local Building Regulations,
the Current I.E.E. Wiring Regulations and the bye laws of the
Local Water Undertaking. Where no specific instructions are
given, reference should be made to the relevant B.S.
CODES OF PRACTICE.
3. All systems must be thoroughly flushed and treated
with inhibitor (see section 3.2).
1.3 B.S. Codes of Practice

5
2.0 Technical Data - Page 5
Bermuda Inset 2 Boiler 50/4
The Boiler is for use with Natural Gas only.
Inset 2 50/4 hydraulic resistance Heat Input
kW
Btu/h
Heat Output
kW
Btu/h
Burner Pressure
mbar
in wg
Water Content
litres
gallons
Thermocouple
Output
Max
18.79
64,100
Max
14.65
50,000
Max
17
6.8
Max
1 6
0.35
9.5 - 11 5mv
Mid
17
58,070
Mid
13.19
45,000
Mid
14
5.6
Min
15.2
51,850
Min
11.72
40,000
Min
11
4.4
SEDBUK Declaration For Inset 2 50/4
The seasonal efficiency (SEDBUK) is 72 %
This 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 certified by 0086.
Gas Connection
Water Connections
Electricity Supply
Controls
Gas Rate
(after 10 mins)
Lifting Weight
Rc½ (½ in BSPT)
3 x 1 in BSP
230V ~ 50Hz
External fuse - 3 Amp
Appliance Rating - 4.8 watt
Multi-functional gas valve, mechanical thermostat,
thermocouple with permanent pilot & atmospheric
sensing device
1.8m3/h
(63.57ft3/h)
32.1 kg (70.7 Ibs)
Dimensions
Flue Diameter
mm
in
Heat Exchanger
Low Head
mm
in
Height
Width
Depth
125
5
Cast Iron
(Min)
1000
393/8
516mm
440mm
368mm
Water Content Fully pumped or pumped heating with gravity hot
water. Sealed system with optional overheat
thermostat

6
3.0 System Details - Page 6
3.1 Water Circulating Systems
1. The appliance is suitable for open vented systems which
are either fully pumped or pumped central heating with
gravity domestic hot water.
2. An optional overheat thermostat kit is available where
additional control protection is required and for sealed
system applications. This must not be used on gravity
systems.
3. The following conditions should be observed at all
times: •The static head must not exceed 30m (100ft)
of water.
•The boiler must not be used with a direct
cylinder.
•Drain cocks should be fitted to all system low
points.
•All gas and water pipes and electrical wiring
must be installed in such a way that they do
not restrict the servicing of the boiler.
•Position isolating valves as close as possible
to the circulating pump.
3.2 Treatment of Water Circulating Systems
For optimum performance after installation, this boiler and its
associated central heating system must be flushed in
accordance with the guidelines given in BS7593: 1992
“Treatment of water in domestic hot water central heating
systems”. This must involve the use of a proprietary
cleanser, such as BetzDearborn’s Sentinel X300 or X400, or
Fernox’s Superfloc.
Full instructions are supplied with the products, but for
immediate information please contact BetzDearbom (0151
420 9563) or Fernox (01799 550811).
For long term protection against corrosion and scale, after
flushing it is recommended that an inhibitor such as
BetzDearborn’s Sentinel X100, or Fernox’s MB-1 or Copal is
dosed in accordance with the guidelines given in
BS7593:1992.
Failure to flush and add inhibitor to the system will
invalidate the appliance warranty.
It is important to check the inhibitor concentration after
installation, system modification and at every service in
accordance with the manufacturer’s instructions. (Test kits
are available from inhibitor stockists.)
For information or advice regarding any of the above contact
the Baxi Helpline.

7
3.0 System Details - Page 7
3.3 Pipework
1. The sizes of the flow and return pipes from the boiler
should be determined by normal methods according to the
requirements of the system.
2. It is recommended that the system is designed for an
11°C (20° F) drop in temperature across the system.
3.4 System Controls
1. For optimum operating conditions, the system in which
the appliance is installed should include a control system.
2. Such a system would comprise a timer control and a
separate room and/or cylinder thermostat as appropriate.
3. The boiler should be controlled so that it operates on
demand only.
4. It is not economical to rely on the boiler thermostat to
control operation of the system.
3.5 Fully Pumped System (Fig. 3)
1. The sizes of the system pipes should be determined by
normal methods.
2. The open vent pipe should be a minimum of 22mm and
must rise continuously to a point above the teed and
expansion tank.
3. The flow pipe from the boiler may form part of the vent
pipe. No part of the open vent should contain a valve.

8
3.0 System Details - Page 8
3.6 Overheat Kit & Sealed Systems
1. An overheat thermostat kit is available to facilitate the
installation of a Bermuda Inset 2 boiler to systems
incorporating a combined feed and vent and to flats and
dwellings where the building design prevents the boiler vent
pipe rising continuously to the feed and expansion tank.
(This must not be used on gravity systems.) Baxi Part N°
234885.
2. The boiler can be applied to a sealed system with the use
of the overheat kit.
3. Information regarding the application of the overheat
thermostat is included with the kit.
3.7 Storage Systems
1. For information regarding the use of a Bermuda Inset 2
boiler with a storage system, contact the appropriate storage
system manufacturer.
3.8 Pumped Heating & Gravity Hot Water (Fig. 4)
1. The sizes of system pipes should be determined by
normal methods.
2. The gravity flow pipe should rise vertically as close as
possible to the boiler, avoiding sharp bends and tight
elbows.
3. The open vent pipe should be a minimum of 22mm and
must rise continuously to a point above the feed and
expansion tank.
4. The flow pipe from the boiler may form part of the vent
pipe.
5. No part of the open vent should contain a valve.
6. The brass injector tee must be fitted to the boiler return
on all systems incorporating a gravity circuit.
7. The circulating head should not be less than 1 m (3ft)
with a maximum horizontal run of 3m (10ft) when using
28mm pipes. Smaller pipe sizes and longer horizontal runs
are acceptable with suitably increased circulating heads.
8. The gravity circuit should be designed with a minimum of
restriction, avoiding possible air traps and long horizontal
runs.
9. The system should be designed to prevent gravity
circulation in the heating system when the pump is not
running.

9
4.0 Site Requirements - Page 9
4.1 Builders Opening (Fig 5)
1. The boiler unit is designed to fit within a standard builders
opening, the minimum dimensions of which are as shown.
Height 584mm (23in)
Width 584mm (23in)
Depth 375mm (14¾in)
2. The opening should be soundly constructed of brick, pre-
cast concrete or be a proprietary builders opening.
3. The base of the opening should be sound and non-
combustible and must be flat and level.
4. The base of the builders opening should be at the same
height as the finished level of the hearth.
IMPORTANT: If a false chimney breast is intended to
house the boiler, a simulated builders opening, within
the breast, must be provided.
5. The builders opening must not communicate with voids,
pipe ducts or spaces other than the room in which the
appliance is situated.
4.2 Location
1. The appliance must be installed in the living space of a
dwelling.
2. Restrictions to the siting of the appliance are covered by
BS 5546. The appliance may not be installed in bathrooms,
shower rooms, bedrooms or bed sitting rooms.
4.3 Fireplace Opening & Surround
1. If a fireplace surround is to be used, it must be centrally
placed and have opening sizes and a vertical flat area as
detailed in the Installation and Servicing Instructions for the
fire.
4.4 Frame Extension Kit
1. If the depth of the builders opening is less than the
375mm minimum specified, it can be increased by the use of
the Frame Extension Kit.
2. Kit N° 234887 is suitable for use with Inset 2 TS, BS and
FS models.
For Inset 2 KS, Kit N” 239341 must be used.
3. Full installation details are included in the kit.

10
4.0 Site Requirements - Page 10
4.5 Flue
1. The flue installation must conform to BS 5440 Pt 1. The
flue must have a minimum vertical height of 3m (10ft) and
have a minimum internal cross section area of 12,700 mm2
(20in2), this is satisfied by a flue of 125mm (5in) internal
diameter.
A suitable terminal is required for all installations.
2. 9in x 9in Brick
Flues previously used for other fuels must be thoroughly
swept. The flue must be lined with a 125mm (5in) flexible
liner. The bottom of the liner should terminate 500mm (20in)
above the base of the builders opening. The flue must be
sealed between the liner and the brickwork at both the top
and bottom.
An approved terminal must be installed.
3. Acid Resistant Liner
A flue constructed of acid resistant liners is satisfactory
provided the size requirements are met. The boiler flue outlet
can be connected to the flue by means of a short length of
125mm (5in) of flue pipe. A seal must be made in the
annular space between the outer face of this flue pipe and
the acid resistant liner.
An approved terminal must be installed.
4. Precast Flues
These must conform to BS 5440 Pt 1 and be correctly
installed without intrusion of cement into the flue passage.
An approved terminal must be installed.
5. Proprietary Flues
A flue of this type must meet the size requirements specified
and be installed in accordance with the flue manufacturers
recommendation and relevant codes of practice.
An approved terminal must be installed.

11
4.0 Site Requirements - Page 11
4.6 Ventilation
1. Ventilation air supply to BS 5440 Pt 2 is required. The
permanent ventilation area size requirements are as shown:
80.1cm2(12.42in2)
2. The permanent vent may be directly into the room
containing the appliance. The vent may also be sited in
another (not a bedroom, toilet, bathroom or kitchen) room
provided an interconnecting vent is used.
3. The vent must not be installed inside the builders
opening. The vent should be sited following good practise for
a habitable room. We recommend the use of the Stadium
BM720 “Black Hole” ventilator which is available from your
local merchant.
4.7 Gas Supply (Fig. 6)
1. The gas installation should be in accordance with BS
6891. The connection at the appliance is Rc ½ (½ in BSPT
internal) located at the rear of the gas cock.
2. Ensure the pipework from the meter to the appliance is of
adequate size. It is necessary to route the gas supply pipe to
the right hand side of the builders opening. It must be routed
so as not to restrict the installation and servicing of the
appliance.
4.8 Electrical Supply (Fig. 7)
1. External wiring must be correctly earthed, polarised and
in accordance with current lEE wiring regulations. The mains
supply is 230V ~ 50Hz fused at 3A A permanent live
supply is required for Deluxe Model Firefronts.
NOTE: The method of connection to the electrical
supply must facilitate complete electrical isolation of the
appliance. Connection may be made via a fused double
pole isolator with a contact separation of at least 3mm
on all poles and serve the appliance and system
controls only.
2. The cable within the builders opening should be 0.75mm2
to IEC 53 code 227 (heat resistant).
3. It is preferable to route the electrical supply cable to the
left hand side of the builders opening. If however it must
come from the right hand side it must be routed via the clips
provided and not restrict the servicing of the appliance (Fig.
6).
4. The cable must be routed to avoid contact with the metal
combustion box and hood.

12
5.0 Installation - Page 12
5.1 Initial Preparation
1. Remove the outer carton from the boiler pack and locate
the fitting kit. Remove and discard the packing pieces.
2. Remove the boiler hood from it’s packing on top of the
boiler. The hood may be fitted now or when the boiler is in
situ. Use the four nuts and set screws provided (Fig. 8).
3. The boiler as supplied has the flow and return water
connections at the left hand side of the appliance.
5.2 For installations requiring the water connections at
the right hand side proceed as follows:
1. Remove the thermostat capillary from its clip. Withdraw
the thermostat phial from the pocket. Lift away the insulation
pad (Fig. 8a) and unfasten the four screws retaining the
boiler door and remove. Remove the rubber seal and
thermostat protection cover (Fig. 9).
2. Lift out the 3 heat exchanger baffles, noting their
orientation (Fig. 10).
3. Lift the heat exchanger from the appliance and remove
the side blanking plate (Fig. 11).
4. Transfer the 3 sealing rings from the holes in the left hand
side of the boiler to those in the right (Fig. 11).
5. Rotate the heat exchanger to place the water connections
at the right hand side, return the heat exchanger to the
combustion box.
DO NOT TURN THE HEAT EXCHANGER UPSIDE DOWN
NOTE: The heat exchanger is correctly oriented when
the three water connections line up with the holes in the
right hand side of the combustion box and the
thermostat pocket aligns with the corresponding hole in
the door. The unfinned heat exchanger water tubes face
the burner.
6. Remove the blanking disc from the left hand hole in the
boiler door and replace with the rubber seal and thermostat
protection cover. Fit the blanking disc into the right hand hole
(Fig. 12).
7. Replace the heat exchanger baffles and blanking plate.
Refit boiler door. Refit the thermostat phial into the pocket.

13
5.0 Installation - Page 13
5.3 Connecting the Sensing Pipe
1 Remove the protection cap from the sensing pipe adaptor
on the burner mounting plate. Slacken the screw retaining
the sensing pipe ‘P’ clip (Fig. 13 & 15).
2. Manoeuvre the pipe so that the flared end aligns with the
adaptor. Engage the nut on the adaptor and tighten finger
tight. Tighten the ‘P’ clip retaining screw and tighten the nut
onto the adaptor using a suitable spanner (Fig. 14 & 15).
IMPORTANT: The sensing pipe must be connected to
enable the appliance to function safely and correctly.
5.4 Siting the Boiler
1. The fireplace and builders opening should be as
described under ‘4.0 Site Requirements’ and be clean,
sound and level.
2. The flue should be installed as described under ‘4.0 Site
Requirements’.
3. It may be desirable to insert the required fittings into the
heat exchanger at this point, depending on the size of the
fireplace opening and whether or not the gravity injector tee
is to be used.
4. Locate the centre line of the finished opening and hearth
(Fig. 16).
5. Hold the boiler by its combustion box at either side of the
heat exchanger, lift from the packing base and place into the
opening.
6. Align the boiler centrally using the “V” mark on the front
centre of the appliance base. Check the distance between
each side of the base and opening. They should be equal
(Fig. 16).
7. The front edge of the base tray must align with the
finished front face of the wall or surround.
This is important for correct installation of the firefront.
5.5 Securing the Boiler
1. It is important that the boiler is secured to the base of the
builders opening.
2. Check the alignment within the opening is correct.
3. The hearth should be drilled as follows: Mark the hearth
through the two slots in the base. Remove the boiler and drill
the hearth. Insert the plugs supplied in the kit. Replace the
boiler. Secure the boiler with the two screws.

14
5.0 Installation - Page 14
5.6 Water Connections
1. The boiler has one return and two flow tappings. Rc1 (1in
BSP). The flows are the two upper tappings. The return is
the lower position tapping and is marked RETURN. It is
essential the flow and return pipes are connected to the
correct tappings.
5.7 Fully Pumped Systems (Fig. 17)
1. A 1in x 22mm threaded adaptor, compression nut and
olive are provided in the kit for the return connection.
2. The 1in x 22mm threaded adaptor provided must be fitted
to the lower tapping marked RETURN. Connect the pumped
return into the adaptor using the nut and olive.
3. Fit a 1in x 22mm threaded adaptor into one of the higher
tapping positions marked FLOW and connect the pumped
flow into the adaptor.
4. Fit a 1in plug to the remaining connection.
6. Follow the instructions under ‘System Details’ as regards
the vent pipe and cold feed.
5.8 Overheat Thermostat
1. For systems requiring an overheat thermostat, an
optional kit is available. (Baxi Part N° 234885). The flow pipe
arrangement for this type of installation is covered in the
instructions supplied with that kit.
2. This kit is not suitable for systems where a gravity
domestic hot water circuit is used.

15
5.0 Installation - Page 15
5.9 Pumped Heating & Gravity Hot Water (Fig. 18)
1. A 1in x 22mm threaded adaptor, two compression nuts
and olives and a brass injector tee piece are provided in the
kit for the return connection.
NOTE: The injector tee must be fitted to the return of all
systems with gravity domestic hot water.
2. The 1in x 22mm threaded adaptor provided must be fitted
to the lower tapping marked RETURN.
3. Fit the injector tee into the adaptor. The injector tee may
be oriented as shown to facilitate connection to the gravity
return pipework.
4. Connect the pumped return to the 22mm compression
fitting of the injector tee..
5. Take the gravity hot water return pipe to a level beneath
that of the injector tee and connect upwards to the 28mm
branch of the injector tee, oriented as shown.
6. Connect the pumped flow to one of the connections
marked FLOW. Connect the gravity flow to the remaining
connection.
7. The gravity flow pipes must rise vertically as close as
possible to the appliance. Ensure the pipework is routed
such that it does not introduce an airlock in the boiler.
8. Follow the instructions under system details as regards
the vent pipe and cold feed.
5.10 Gas Connection (Fig. 19)
1. Connection to the gas supply is Rc ½ (½ in BSPT)
internal located at the rear of the gas cock. The gas supply
pipe must be routed from the right hand side.
2. The positioning of the gas supply pipe must not restrict
the servicing of the appliance or installation of the fire.

16
5.0 Installation - Page 16
5.11 Electrical Connection
1. The appliance requires an electrical supply from the
heating controls system.
2. A permanent live supply is required for Deluxe Model
Firefronts.
WARNING: The appliance must be earthed. The input
cable for the appliance should be 0.75mm2to lEC Code
227 (heat resistant). The system external controls and
the appliance must be supplied by the same isolator.
5.12 Making the Electrical Connection
1. Undo the two screws holding the electrical plug, socket
and heat shield to the left hand side of the base tray (Fig.
20).
2. Disengage the lugs on the socket from their slots (Fig.
21). Pull the mains input plug from the inlet socket (Fig. 22).
3. Remove the screw and cover from the socket (Fig. 23).
4. Remove the rear cable grip and connect the supply cable
(Fig. 24) as follows:
•Control system switched live to L1
•Control system neutral to N
•Earth to the terminal screw adjacent to the
input plug
5. For Deluxe firefronts connect the permanent live supply
L2 (Fig. 24a). Remove the side cable clamp and connect the
wire from the firefront kit as indicated
•Brown (live) to L2
•Blue (neutral) to N
•Green & Yellow (earth) to the terminal screw
adjacent to the input plug.
6. The earth wire(s) should be sufficiently long that if the
supply cable is pulled the live and neutral wires become taut
before the earth.
7. Replace the cable grip(s), ensuring the outer insulation is
firmly held and replace the socket cover and screw.
8. Refit the socket to the plug and re-engage the tugs in the
base tray. Resecure with the two screws, locating the heat
shield with the forward screw.
9. Ensure that all cables are routed away from the boiler
casing and hood, making use of the clips on the front edge
of the boiler base tray as required.

17
5.0 Installation - Page 17
5.13 Overheat Thermostat
1. Where an overheat thermostat kit is required, the wiring
instructions supplied in the kit should be followed.
5.14 Flue Connection (Fig. 25)
1. If not already done so, fit the boiler hood now. Locate the
flue within the flue socket and secure with the three self
tapping screws provided in the kit.
2. Seal the flue against the flue outlet socket.
5.15 Completion
1. Seal off any secondary openings within the builders
opening after wrapping the gas and water pipes through the
brickwork and within the opening itself. (B.S. 5871 Part 1).

18
6.0 Commissioning the Appliance - Page 18
6.1 Commissioning the Appliance
1. Reference should be made to BS 5449 section 5 when
commissioning the boiler and system. Flush the whole
system in accordance with BS7593:1992. (See Treatment of
Water Circulating Systems section 3.2). Check the system
for leaks.
2. Turn the gas service cock ¼ turn from the off position
(Fig. 26). This will supply gas to the boiler only. Purge the air
from the gas service pipe in accordance with BS 6891 and
test for gas soundness.
3. Turn the boiler thermostat to the OFF position (Fig. 27)
and ensure that all external controls e.g. room stat, timer etc
are calling for heat and turn on the mains electrical supply.
4. Slacken the test point sealing screw and connect a
pressure gauge (Fig. 31).
5. Hold in the grey button on the gas control valve (Fig. 29),
press the piezo igniter button and release (Fig. 28). Repeat
until the pilot lights. Hold in the grey button for a further 15
seconds (Fig. 29).
6. The pilot should remain alight. If not, turn the grey button
clockwise and wait 3 minutes before repeating the
sequence.
7. The pilot side flame should be without a yellow tip and be
approximately 16mm (5/8in) long. The pilot upper flame
should be approximately 25mm (1in) long. It is not possible
to adjust the pilot.
8. Operate the burner by turning the boiler thermostat knob
to the HIGH setting and check the operation of the flame
failure device by turning the grey button clockwise. The
burner and pilot should extinguish.
9. Turn the boiler thermostat to the “O” position, wait 3
minutes and relight the pilot as previously described.
10. Operate the burner and allow the system to reach
normal operating temperature. Make further checks for leaks
and check the burner setting pressure, adjusting if
necessary. This is done by removing the governor cover
screw and adjusting the governor in either direction as
required.
11. Remove the pressure gauge and tighten the pressure
test point sealing screw.
12. The boiler and system should be run and then flushed
and treated in accordance with BS7593: 1992 and the
flushing agent/inhibitor manufacturers instructions. When all
the air has been removed from the water circuit, the pump
and radiators should be balanced to achieve the design
temperature drop across the system.
13. Recheck the system for leaks. Turn the boiler
thermostat to the required setting.
14. Carefully read and complete all sections of the
“Benchmark” Installation, Commissioning and Service
Record Log Book that are relevant to the appliance and
installation. The details of the Log Book will be required in
the event of any warranty work. The Log Book must be
handed to the user for safe keeping and each subsequent
regular service visit recorded.

19
7.0 Annual Servicing - Page 19
7.1 Annual Servicing
1. To perform annual servicing of the back boiler it is
necessary to remove the firefront.
2. After servicing, complete the relevant section of the
“Benchmark” Installation, Commissioning and Service
Record Log Book. This should be in the possession of the
user.
7.2 Removal of Firefront
1. Isolate the electrical supply to the appliance.
2. Turn the gas service tap to the off position (Fig. 34).
3. Refer to the separate firefront instructions for the removal
of the firefront.
7.3 Removal of Controls
1. Turn the boiler thermostat to “O” position (Fig. 36).
2. Undo the retaining screw and remove the heat shield and
electrical plug from the socket (Fig. 35).
3. Disconnect the union at the gas service cock and remove
the fire feed pipe.
4. Remove the thermostat phial from the boiler (Fig. 38).
5. Lift and remove the injector insulation pad (Fig. 37).
6. Undo the nut on the sensing pipe at the adaptor.
7. Undo the four screws retaining the door and remove the
door (Fig. 38).
8. Undo the two screws retaining the controls to the
combustion box sides (Fig. 39).
9. Slacken the screw holding the controls to the combustion
box base tray.
10. Withdraw the controls from the boiler.

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7.0 Annual Servicing - Page 20
7.4 Cleaning the Lint Arrestor
1. Remove the controls cover panel from its retaining clips
(Fig. 41).
2. Remove the lint arrestor from the controls and clean
away any deposits (Fig. 40).
7.5 Cleaning the Burner & Main Injector
1. Remove the four hexagon headed screws holding the
burner to the burner mounting plate (Fig. 42).
2. Carefully clean any deposits from the burner blades and
venturi inlet (Fig. 42).
3. Remove the injector from the feed pipe, retaining the
copper sealing washer. Clean the injector and reassemble in
reverse order (Fig. 43).
4. Reassemble the burner and pilot in reverse order and
refit the lint arrestor.
7.6 Cleaning the Pilot/A.S.D. Assembly (Fig 44)
NOTE: No attempt should be made to clean the device
using any hard tools, including pins or wire.
WARNING: The pilot/A.S.D. assembly must not be
adjusted in any way.
1. The A.S.D. must not be altered so that it will not operate
or be bypassed in any way.
2. Ensure that the pilot burner aeration hole is free from lint,
debris etc.
3. If necessary clean the electrode and target, and check
that the spark gap is 2.5 - 4.0mm.
4. The thermocouple cannot be changed as an individual
component. The complete assembly must be replaced in the
event of one or other component failure(s).
5. Only use a Genuine Baxi Spare Part.
6. Reassemble the burner in reverse order and refit the lint
arrestor.