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SECTION 3 - SERVICING
3.31 HEAT ENGINE REPLACEMENT
Refer also to Section 1.3 - ‘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 Section 3.8.
2.
Drain the boiler. Refer to Section 3.19.
3.
Remove the fan / venturi assembly and place on one side.
Refer to Section 3.9.
4.
Remove burner and place on one side. Refer to Section 3.10.
5.
Remove the ignition/detection electrode. Refer to Section
3.12.
6.
Remove the spark generator. Refer to Section 3.13.
7.
Remove the gas valve. Refer to Section 3.14.
8.
Remove the expansion vessel. Refer to Section 3.32.
9.
Remove the flow thermistor. Refer to Section 3.29.
10.
Remove the 2 M5 screws retaining the gas valve mounting
bracket and transfer bracket to the new heat exchanger.
11.
Undo the return pipe union nut, swing the pipe and pull
down to remove from heat exchanger.
12.
Pull out the flow pipe spring clip, pull the pipe down and
twist towards you (allows clearance of the pipe from heat
exchanger plugs). Lift pipe and remove.
13.
Remove the two heat exchanger fixing screws.
14.
To
remove the Heat exchanger slide out of location bracket.
15.
Remove the condensate rubber pipe from the sump.
16.
If replacement sump required: Rotate heat exchanger
assembly 180º. Place new sump onto heat exchanger,
ensuring correct orientation and seal is in place. Then
gently apply pressure to the base of the sump at each tab
fixing point and engage tabs onto 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 the return
pipe connection, ensure clip is oriented to correctly match
connecting pipe diameters.
18.
Ensure the trap/siphon is filled with water. Refer to
Section 3.16.
19.
Refill the boiler and add the correct volume of anti-freeze.
20.
Ensure all gas valve connections are gas tight with a gas
soundness check up to the gas control valve.
21.
Check operation of the boiler.
16
Shown as 180º position
14
11
12
13
10
