54
Response FF80
- Installation
84 Power to PCB 37 but burner pressure incorrect or zero
NO
Clear the blockage and take steps to
prevent recurrence
NO
Are air and flue ducts free from blockage ?
Check all items connected to PCB 37
for short circuits between Live and
Neutral, also between Live and Earth.
If none found, reconnect one by one
(gas valve last) until the faulty item is
found.
If no fault found or fuse blows with no
items connected, check PCB 37 by
substitution.
Is the appliance gas cock fully open ?
NO
NO
Is the gas supply pressure adequate at the
appliance inlet during an ignition trial period
(i.e. when LED 2 on PCB 37 goes off) ?
NO
YES
Contact the
gas
supplier
Is the supply pressure correct at the
gas meter ?
Rectify the fault and take steps to
prevent recurrence
NO
Are the fan and burner pressure sensing
pipes correctly connected, free from
damage and unobstructed by solid matter
or moisture ?
Is there Live on the brown lead of the gas
valve connector on PCB 37
during an
ignition trial period
?
Are both connectors correctly fitted to the
gas valve, with screws secured
but not
overtightened ?
Remove connectors. With mains OFF,
check continuity of leads from each socket
unit back to the corresponding terminals in
the control box. Are leads in good order ?
Check gas valve by substitution
Change lead assembly
Return
to main
menu
YES
YES
YES
YES
YES
YES
YES
YES
NO
Notes.
1.
The burner pressure is not user-adjustable: it is regulated by the gas valve, according to the air flow generated by the fan and, on
cold ignition, should be slightly higher than the value quoted on the Data Plate. Long flues will cause a slightly lower burner
pressure than standard flues.
2.
Equilibrium fan differential pressures should be as detailed in Frame 45.
Determine the cause of
pressure loss (e.g. supply
pipe too small ?) and rectify
Check PCB 37 by substitution
FAULT FINDING
Is the fuse good on PCB 37 ?
(LED3 lit confirms this
F
AUL
T FINDING