Saunier Duval ISOFAST CONDENS F 35 E Instructions For Use Installation And Servicing page 34

INSTALLERS
Replacement of
parts
Expansion Vessel the heat exchanger.
For access, refer to section Move the pipes away from
"General". the heat exchanger.
Refer to page 57 and drain Loosen the three heat
the boiler heating circuit. exchanger securing screws
Undo the coupling at the and clamps (two at the top
base of the vessel, see and one at the bottom) to
diagram 8. remove the heat exchanger,
While holding the vessel see diagram 9.
remove the securing bolt on CAUTION: There will be
the top panel of the boiler. water in the heat exchanger.
Remove upper support Remove condense pipe
bracket. connector from bottom of
Lift the vessel up, draw heat exchanger.
bottom out to the left, lower Carefully ease heat
and remove. exchanger out.
Fit the replacement unit.
Fit a new gasket between Flue Hood
the expansion vessel and For access, refer to section
coupling. "General".
Refill, vent and pressurise Remove heat exchanger as
the boiler. per previous section.
Check for leaks. Remove the two securing
screws and pull the flue
Heat Exchanger hood down and away from
For access, refer to section the flue hood bracket and
"General". flue elbow, see diagram 10.
Refer to pages 54 and 55
for removal of the fan, gas Diverter Valve Motor
valve and burner assembly. For access, refer to section
Drain the boiler heating "General".
circuit, and the hot water Refer to diagram 11.
circuit see page 57. Remove the electrical plug.
Remove the clip securing Unscrew the retaining nut.
the clear condense pipe to Remove the diverter valve
heat exchanger. motor.
Pull to remove the clear
condense pipe out of the Pump (head only)
bottom of the heat For access, refer to section
exchanger. "General".
Undo the two nuts of the Drain the boiler heating
flow and return pipes from circuit.
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Refer to diagram 12.
Remove the four cap head
Expansion
screws.
vessel
Carefully remove the pump
head together with cable.
Do not strain cable.
Support the pump head,
unscrew cable cover at the
side of pump head and take
off.
Disconnect wiring from
pump head.
Reconnect wiring to new
Diagram 8
pump head and fit cover.
Fit the new pump head with
Flow and return
'O' ring.
pipe nuts
Refill, vent and pressurise
the boiler.
Check for leaks.
Safety Discharge Valve
For access, refer to section
"General".
Drain the boiler heating
circuit.
Refer to diagram 13.
Undo the safety discharge
Securing screws
valve union and remove
and clamps
from the pipework.
Diagram 9 Remove the securing clip
and withdraw the safety
Flue hood discharge valve.
bracket Fit new 'O' ring.
Refill, vent and pressurise
the boiler.
Check for leaks.
Flue
hood
Domestic Hot Water
Thermistor
For access, refer to section
Securing "General".
Diagram 10 screws (2)
Drain the boiler domestic
Cable
cover
Electrical
plug
Pump
head
Diverter valve
motor
Diagram 11
Diagram 12
hot water circuit.
Refer to diagram 14.
Disconnect the domestic
hot water thermistor
electrical connections
Remove retaining clip.
Withdraw domestic hot
water thermistor from its
housing.
Note : When reconnecting
electrical connections,
polarity is not important.
Diagram 13
Fit new 'O' ring.
Carry out a functional test of
the controls.
Heating Flow Thermistor
For access, refer to section
"General".
Refer to diagram 15.
Remove the electrical
connections from the
thermistor.
Remove the retaining clip
from the flow pipe.
Note: When reconnecting
the polarity of the wiring to
thermistors is unimportant. Diagram 14
cap head
screw (4)
Safety
discharge
valve
Domestic
hot water
thermistor
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