13.0 Fault Finding
43
Fault Finding Solutions
Is there 230V at:
Main terminals L and N
Check electrical supply
1.
NO
Main terminal fuse
Replace fuse
Replace neon PCB
If problem is not
solved replace
main PCB
neon
illuminated
2.
NO
Both sides of suppressor
Replace suppressor
3.
NO
NO
PCB M6 connector, terminals 18,19
Check wiring
4.
NO
A
If pump jammed, release
Replace pump
1.
NO
Main PCB M1 connector, terminals 1,2-230V
Replace main PCB
2.
NO
Change pump supply cable
3.
YES
B
CH system pressure 0.5 to 1.5 bar
Gas at burner
Re-pressurise system
1.
NO
Primary flow valve diaphragm damaged
Replace diaphragm
Flow valve rod obstructed
3.
YES
Check the tap of the automatic
air vent is opened
Check the water valves are opened
2.
NO
NO
C
YES
Continuity across primary flow
microswitch and main PCB M7
connector, terminals 24,25
Replace microswitch
1.
NO
NO
DHW / primary temp. sensor faulty cold
resistance approx. 11K ohms
(resistance reduces with increase in temp.)
Replace sensor
2.
YES
Fan connections correct at fan
and ignition PCB
Ignition PCB M2 connector, is
230V across terminals 17,18
Fan jammed or faulty winding
Replace ignition PCB
Replace fan
YES
3.
D
Air pressure switch 230V
across terminals NO & C
Ensure gas is on and purged
Replace ignition PCB
Replace gas valve
Replace
ignition PCB
Flame failure reset button illuminated
230V at gas valve and across ignition PCB -
M1 connector, terminals 1,2
230V at ignition PCB - M1 connector,
terminals 5,6
Check and correct if necessary
1. Electrical and pressure tube connections
2. Blockage of pressure tubes
3. Restriction in flue
4. Venturi
YES
YES
Press to reset
YES
Replace reset button
YES
NO
NO
NO
NO
NO
NO
E
neon stays off
Replace air
pressure switch
F