Supplied By www.heating spares.co Tel. 0161 620 6677
17
221481C
10 Servicing and Replacement of Parts
Diagram 10.2
PILOT ASSEMBLY
M3
SCREW
IGNITION
LEAD
(clear end)
MICA WINDOW
PILOT
INJECTOR
PILOT
TUBING NUT
ADAPTOR
OLIVE
THERMOCOUPLE
THERMOCOUPLE
NUT
PILOT
SHIELD
SECURING
SCREWS
ELECTRODE
1049
10.6 Over Heat Cutoff
Generally follow the information under Section 10.3.
Remove the two screws securing the over heat cutoff to the
clamp, see diagram 10.5.
Release connections at the gas valve, see diagram 10.6.
Release but do not remove the two screws securing the front
and rear gland plates, see diagram 10.4 and withdraw the cutoff
leads.
When refitting smear a little of the heat sink compound, supplied,
between the face of the cutoff and the water pipe, ensure that
it is correctly located on the pipe.
10.7 Gas Valve
See diagram 10.6.
Gain access as under Section 10.3.
Remove screw to release gas valve cover.
Disconnect all leads and pipes at the valve.
Undo the four screws each side of the valve to release the
service cock and burner supply tube, take care not to damage
to “O” rings.
Re-assembly note, when refitting the gas valve take care not to
damage the “O” rings.
Remake all connections.
Do not tighten the thermocouple nut more than a quarter turn
beyond finger tight.
It will be necessary to purge the pipework and valve before
relighting - refer to Commissioning.
10.8 Electrical Control Box
Remove controls cover and outer casing as Section 10.1.
Remove retaining clip from the boiler thermostat phial pocket
and withdraw the phial, see diagram 10.5.
Remove the control box by undoing the two fixing screws at the
front and lower the front of the box until it is clear of the cover.
Push the box towards the rear of the boiler to disengage the
hinge and lower, see diagram 7.1.
Diagram 10.3
PILOT FLAME & SPARK GAP
14 to 17 mm
14 to 17 mm
ELECTRODE
THERMOCOUPLE
SPARK GAP
3 to 4 mm
1053
RELEASE SCREWS
DO NOT REMOVE
AND PULL FRONT
GLAND PLATE FORWARD
REAR
GLAND
PLATE
GLAND PLATE
Diagram 10.4
IGNITION
LEAD
OVERHEAT
CUT-OFF LEADS
THERMOSTAT
CAPILLARY
THERMO-
COUPLE
PILOT
TUBE
FRONT GLAND
PLATE
0394
Release, but do not remove, the two screws securing the front
and rear gland plates. Pull the gland plates forwards, see
diagram 10.4.
Withdraw the thermostat capillary through the bottom of the air
duct.
Disconnect cables (a) mains, L.N.E. (b) pump at terminal 8, 7
and earth stud, (c) cables at gas valve, (d) disconnect any
remote controls at terminal 9 and SL.
When replacing refer to diagram 7.2 for electrical connections.
Smear the thermostat phial with heat sink compound and
ensure it is secured, with the retainer, in the pocket.