45
FAULT FINDING
F
AUL
T FINDING F
AUL
T FINDING F
AUL
T FINDING F
AUL
T FINDING F
AUL
T FINDING F
AUL
T FINDING
IMAX XTRA EL
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Installation & Servicing
55 OVERHEAT LOCKOUT
Has PCB just been replaced?
Reset Boiler
yes
no
Are the boiler and CH/DHW system
filled with water and are all isolation
valves and radiator valves open?
Fill and vent the system and open all
isolation valves, then reset the boiler.
no
yes
Is the flow/return differential across
the boiler in excess of 35ºC?
Check the flow and return
thermistors (refer to Frame 61)
no
yes
Check that the pump is rotating freely.
Is the differential now below 20ºC?
Replace the pump, then reset the boiler
no
yes
Reset the boiler
56 IGNITION LOCKOUT
If the boiler is reset, does it ignite for a
short time and then extinguish?
Check the detection electrode and associated harness
for continuity, visual condition and position (refer to
Frame 42). Check if the condensate pipe is blocked.
yes
no
Is the dynamic gas pressure available at the boiler >
15mbar?
Check gas supply and rectify fault
no
yes
Is the following voltage available at the Gas Valve?
approximately 240Vac
Check wiring from Gas Valve to PCB
and replace if necessary, otherwise
replace the main PCB
no
yes
Unplug the Gas Valve, is the resistance between the
outside pins between 9-10M
Ω?
Replace Gas Valve
no
yes
Check Spark Generator and associated Harness for
continuity, visual condition and position (refer to Frame
46). Are these functioning correctly?
Replace Spark Generator and
Harness as necessary
no
yes
Replace Ignition Electrode and
associated Harness as necessary
no
Check Ignition Electrode and associated Harness for
continuity, visual condition and position (refer to Frame
42). Are these functioning correctly?
yes
Replace Gas Valve
no
Check Syphon and condensate drain pipework for blockage
and rectify if necessary. Boiler now working OK?
