18
221763A
8 Servicing
8.4 Service Checks
Inspect the thermocouple and pilot burner, clean or renew as
necessary.
Check the condition of the insulation panels in the combustion
chamber, renew if necessary.
Check the condition of the seals on the cleaning door and the
combustion chamber cover, renewing if necessary.
8.5 Reassembly
Make sure that the baffle tray is replaced and secured with the
graphite coated nuts, previously removed.
Make sure that the thermostat phial is fully inserted into the phial
pocket and secured, with the location washer behind the
retaining split pin, see diagram 4.5.
Make sure the flueway baffles are positioned as diagram 8.6
8.6 Operational Checks
Light the boiler and carryout the operational checks as described
in Sections 7.2 and 7.3.
Diagram 8.6
HEAT
EXCHANGERS
BAFFLES
6142
6307
BURNER SERVICING
Diagram 8.5
WASHER
SECURING
NUT
DISTRIBUTOR
BURNER
BURNER
END CAP
1061
Diagram 8.4
REMOVAL OF BURNER
BURNER
SUPPORT
BRACKET
SCREW (2)
GRAPHITE
COATED NUT (2)
COMBUSTION
CHAMBER
COVER
MAIN
BURNER
BURNER
SUPPLY
PIPE
MAIN
INJECTOR
Before removing or replacing any parts, turn the gas off at the
gas service cock, see diagram 8.1 and isolate the electrical
supply to the boiler.
ALWAYS test for gas soundness after replacing any gas
carrying component.
Unless stated otherwise, all parts are replaced in the reverse
order to removal.
9.1 Gas Valve
Gain access to boiler, see Section 8.1.
Disconnect the gas valve plug, thermocouple nut and pilot tube
connections at the gas valve, see diagram 9.1.
Support the valve and remove the four right-hand flange screws
to disconnect the gas valve from the burner supply pipe.
Ease the gas service cock union out and remove the valve
taking care not to damage the “O” ring seal at the flange.
Inspect the condition of the “O” ring seal and renew if necessary.
Remove the union half and refit into the replacement valve on
the inlet, left-hand side. Use a little jointing compound, on the
external thread only, to ensure gas soundness.
It will be necessary to purge air from the gas line after changing
the gas valve, refer to Section 7.2.
9.2 Injector
Gain access to the boiler as Section 8.1.
Unscrew the injector from the manifold and renew as necessary.
When replacing the injector use a little jointing compound, on
the external thread only, to ensure gas soundness.
Replace thermostat phial as Section 8.5.
9.3 Thermocouple
Gain access to the boiler as Section 8.1.
Disconnect the thermocouple by unscrewing nuts at the gas
valve and pilot burner, see diagram 9.1 and 9.2. Withdraw the
thermocouple.
When replacing tighten the thermocouple nut only a quarter turn
beyond finger tight.
9.4 Pilot Burner
Gain access to the boiler as Section 8.1.
Remove the cover and burner controls assembly, as Section
8.2.
Disconnect the ignition lead at the electrode, see diagram 9.2.
Disconnect the thermocouple nut at the pilot burner.
9 Replacement of Parts
