32
SECTION 3 - SERVICING
1.
Refer to Frame 3.8.
2.
Drain the boiler. Refer to Frame 3.21.
3.
Unplug the electrical connection.
4.
Using a suitable tool, pull out the retaining clip.
5.
Carefully pull the thermistor upwards to remove.
6.
Fit the new thermistor and re-assemble in reverse order.
7.
Refill the boiler and add the correct volume of anti-freeze.
8.
Check the operation of the boiler.
3.32 RETURN THERMISTOR REPLACEMENT
3.33 HEAT ENGINE RENEWAL
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 Frame 3.8.
2.
Drain the boiler. Refer to Frame 3.21.
3.
Remove the fan / venturi assembly and place on one
side. Refer to Frame 3.9.
4.
Remove burner and place on one side. Refer to Frame 3.10.
5.
Remove the ignition and detection electrodes. Refer
to Frames 3.12 & 3.13.
6.
Remove the spark generator. Refer to Frame 3.14.
7.
Remove the gas valve. Refer to Frame 3.15.
8.
Remove the expansion vessel. Refer to Frame 3.34.
9.
Remove the flow thermistor. Refer to Frame 3.31.
10.
Remove the 2 M5 screws retaining the gas valve mounting
bracket and transfer bracket to the new heat exchanger.
11.
Undo the inlet 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 to
remove from heat exchanger.
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 Frame 3.17.
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.
3
4
16
Shown as 180º position
14
11
12
13
10
Summary of Contents for GB24
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