Symptoms
Fault
Action
Regardless of the position of the
No power supply to the controller
Check electrical supply-live to
coloured wheel, the controller does not
terminal 9 neutral to terminal 8.
move even when reset.
Faulty controller.
Check by replacement.
Coloured programme wheel rotates
Controller is permanently sensing a
Check to see if there is a flame
continuously
flame
caused by leaking gas valve.
Faulty controller.
Check by replacement.
Flame probe earthing.
Check probe condition if necessary
replace.
Controller on black/blue border and will
Control circuit not complete.
Check continuity to terminal 1 and 9.
not start
Air pressure switch in the normal closed
Check air pressure proving system
position i.e. airflow is sensed.
and coloured program wheel rotates
continuesly.
wiring to air pressure switch. Check
supply voltage greater than 180V.
Lockout ar red line near start of the blue
Air pressure switch is not changing to
Check fan is running i.e. circuit
section.
normally closed position within the first 8
breakers have not tripped.
seconds.
Check air pressure-proving system
and in particular the wiring to the air
pressure switch. Check also
air sensing pipes are not blocked.
Check pilot solenoid valves
connected to terminal 5 or terminal C.
If solenoid coils fitted with rectifier the
negative side must be connected to
terminal 5 or C.
Flame sensing probe earthing.
Reposition or replace flame sensing
probe.
Lockout during the second blue section
Air pressure switch changed back to the
Investigate cause of insufficient
normally open position i.e. insufficient air
air flow.
flow.
Controller senses flame or simulation of
Investigate cause of flame signal
flame.
Pilot flame established for few seconds
Failure to sense pilot flame.
Check position and wiring to flame
seconds but controller locks out at the
sensing probe. Check also the probe
end of the yellow section.
if clean and dry.
Lockout at the end of the yellow section
Pilot flame not established due to a lack
Check that start valve is opening and
section without any appearance of
of gas.
gas is flowing. Also check that gas
pilot flame.
isolation valves are open.
Pilot flame not established due to no
Check spark gap and that spark is
ignition.
present and is arcing in the
correct place. The ignition
transformer is energised via terminal
3 at the end of the yellow section.
Check also that HT lead is in good
condition.
Lockout during red section.
Unsuitable pilot flame.
Check start gas adjustment for
satisfactory flame, small light blue
flame.
Check position of and wiring to flame
sensing probe. Check also that the
probe is clean and dry.
Check if gas is turned on.
Trouble shooting checklist