32
Does the boiler pump
run?
(removal of pump
venter plug may help
identify rotation of
pump)
Switch off mains
supply.
Remove Molex
connector at X6 and
measure the
resistance across the
red wires. Is the
resistance below
50k ohms?
Is the facia
indicator
still on?
Control was in a lock
out condition.
There are two main
causes for this:
gas/ignition problem
or limit thermostat
tripping.
Continue fault finding
sequence:
Replace the Pump.
(Section 15.4.12)
Check or replace
temperature
sensor or sensor
harness.
Replace control board.
(Section 15.4.9)
The system is not
creating a boiler
demand. Refer to
SYSTEM TEST
Is there 230V AC
across both pins of
connection X5?
Drop down the facia
and expose the three
PCB rear connectors.
Is there 230V at pins
3 & 4 of connector
X11?
(centre connector)
Refer to
above section
Does the fan run and
normal ignition
take place?
BOILER DEMAND TEST
No
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Set the system to create a boiler demand. Turn facia control knob to maximum
.
Does the Fan
run?
Press the facia
reset button.
Does the fan run
after approx
20 seconds?
Is there 230V AC
across both pins
of connector
X4?
No
No
Measure the continuity
across the green wires.
Is it open circuit?
Yes
Replace air
pressure switch.
No
Remove Molex connector at X3
and measure the resistance
across the two wires that run to
the gas valve.
Is the resistance between
3000 and 5000 ohms?
Yes
Replace control board.
(Section 15.4.9)
Yes
Replace gas
valve or cable
to gas valve.
No
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