
Supplied By www.heating spares.co Tel. 0161 620 6677
40
221473B
5049
ELECTRICAL
CONNECTORS (2)
SECURING
SCREW
(4+4)
Diagram 4.13
IGNITION UNIT
SECURING
SCREW
IGNITION UNIT
4 Replacement of Parts
SENSING
ELECTRODE
LEAD
IGNITION UNIT
SECURING
SCREW
EARTH
ELECTRODE
LEAD
SPARK
ELECTRODE
LEAD
SECURING
SCREW (2)
5288
Diagram 4.13a
4.14 Gas Valve
Remove control box housing, see Section 4.11.
Remove the user control switch bracket, see diagram 4.6.
Remove the ignition unit securing screw and two electrical
connectors. see diagram 4.13.
Remove ignition unit.
Remove the four extended hexagon screws at the right hand
side of the gas valve,
Support the gas valve, disconnect the union nut at the gas
service cock and remove the valve complete with the inlet pipe.
Separate the valve from the pipe, noting the fitted position.
Discard the “O” rings and fit the new ones supplied.
Fit gas valve cables. The polarity is not important.
Check and adjust the main burner gas pressure in the hot water
and central heating modes, refer to “Commissioning” in the
Installation Instructions.
4.14a Ignition unit
Remove control box housing, see Section 4.11.
Remove the user control switch bracket, see diagram 4.6.
Remove the ignition unit securing screws. see diagram 4.13a.
Disconnect the electrical connector and the three electrode
leads.
Remove ignition unit.
Note: when re-fitting make sure the electrode leads are fitted to
the correct terminals, see diagram 4.13a.
4.15 Central Heating Selector Switch
and Control Reset Switch
Slacken the user control switch bracket securing screws and
remove the bracket from the keyhole slots, see diagram 4.6.
Pull the leads from the switch, see diagram 4.14.
To remove the switch press in the tabs on each side of it.
THE POLARITY OF THE ELECTRICAL
CONNECTORS IS IMPORTANT, see diagram 4.12.
4.16 Modulator
Isolate the boiler from the electrical supply and closethe gas
service cock, refer to Section 1.3
Remove the outer case, refer to Section 1.4.
Disconnect the two electrical connectors at the modulator,
see diagram 4.15.
Remove the modulator, secured with two screws.
Discard the gasket and fit the new one supplied, when
fitting the modulator.
Light, check and adjust the boiler if necessary, refer to
"Commissioning" in the Installation Instructions.
4.17 Domestic Hot Water Flow Switch
Before commencing refer to Section 1.1
Isolate the boiler from the electrical supply, refer to Section 1.3.
Remove the outer case, refer to Section 1.4.
Isolate the domestic hot water inlet, release the domestic water
pressure and drain, refer to Section 1.3 and 1.6.
Remove the control housing, refer to Section 4.11.
Remove the user control switch bracket, see diagram 4.14.
Remove the pressure gauge bracket, see diagram 4.9.
Disconnect the flow switch cables at the inline connectors.
Remove the flow switch by disconnecting the union nuts, see
diagram 4.16, noting the fitted position.
Slacken or remove the clip securing the isolating valve, to ease
removal.
Discard the sealing washers and use the new ones supplied.
It is recommended that the water inlet filter is cleaned or
renewed at this stage.
Make sure that the switch is positioned correctly, with the flow
arrow pointing upwards.