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25
SERVICING INSTRUCTIONS - Page 25
SPARK GENERATOR
a
Carry out operations A,B,C in section 1 PREPARING
BOILER FOR SERVICE.
b
Remove rear locking nut securing spark generator to
its mounting bracket, withdraw spark generator and
pull off electrode lead.
c
Replacement is the reverse of removal.
PUMP OVER-RUN THERMOSTAT
a
Carry out operations A,B,C,D in section 1 PREPARING
BOILER FOR SERVICE.
b
Remove control box securing screw and lower control
box.
c
Access to the pump over-run thermostat is made
easier by separating the upper assembly of the control
box from the boiler base. This is done by removing the
two hexagonal head screws identified in Fig 27 Tilt the
upper assembly and disconnect the electrical wiring
from the thermostat as follows:-
Black from terminal 1
Red from terminal 2
Brown from terminal 3
d
Replacement is the reverse of removal.
e
Follow the full commissioning instructions as described
in the COMMISSIONING section of these instructions.
BOILER THERMOSTAT
a
Carry out operations A,B,C,D in section 1 PREPARING
BOILER FOR SERVICE.
b
Remove control box securing screw and lower control
box.
c Pull off the outer thermostat knob. d Remove inner
thermostat post by undoing the two securing screws. e
Access to the boiler thermostat is made easier by
separating the upper assembly of the control box from
the boiler base. This is done by removing the two
hexagonal head screws identified in Fig 27 Tilt the
upper assembly and disconnect the electrical
connections from the rear of the thermostat as follows:-
White from terminal 3
Brown from terminal 2
Refer to Figs 23 & 24.
f
Remove the nut securing the thermostat to the control
box.
g
Remove the split pin retaining the thermostat bulb and
withdraw bulb from its pocket.
h
Remove split grommet in the base of the boiler and the
split grommet from the side of the control box, and
feed thermostat capillary and bulb through holes.
i
Replacement is the reverse of removal. The bulb of the
new thermostat should be coated with heat conducting
paste. Ensure the split grommet in the base of the
boiler makes a good seal around the capillary.
j
Ensure that the capillary is secure in the clips
provided. Follow the full commissioning procedure as
detailed in the COMMISSIONING section of these
instructions.
OVERHEAT THERMOSTAT
a
Carry out operations A,B,C,D in section 1
PREPARING BOILER FOR SERVICE.
b
Remove control box securing screw and lower control
box.
c
Access to the overheat thermostat is made easier by
separating the upper assembly of the control box from
the boiler base. This is done by removing the two
hexagonal head screws identified in Fig 27 Tilt the
upper assembly and disconnect the two push-on
electrical connections from the overheat thermostat
terminals.
d
Remove the nut securing the thermostat to the control
box.
e
Remove clip securing the thermostat bulb to the pipe.
f
Remove split grommet in the base of the boiler and the
split grommet from the side of the control box and feed
thermostat capillary and bulb through holes.
g
Replacement is the reverse of removal. The bulb of the
new thermostat should be coated with heat conducting
paste. Ensure the split grommet in the base of the
boiler makes a good seal around the capillary.
h
Ensure that the capillary is secure in the clips
provided. Follow the full commissioning procedure as
detailed in the COMMISSIONING section of these
instructions.