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Fault Finding Solutions Sections A to E
A
Is there 230V at:
1.
Main terminals L and N
2.
Main terminal fuse
3.
Selector terminals a & b
and a & 3. PCB - A4
connector terminals 4 & 5
B
Is there 230V at:
NO
1.
Pump
2.
PCB - A4 connector terminals 3 & 6
YES
Change pump supply cable
C
1.
CH system pressure 0.5 to 1.5 bar
2.
Check the tap of the automatic
air vent is opened
3.
Primary flow valve diaphragm damaged
D
1.
Continuity across flow
microswitch and PCB - A5
connector terminals 7 & 8
2.
Primary temperature sensor faulty.
Cold resistance approx. 11K ohms
(resistance reduces with increase in temp.)
3.
Fan connections correct at fan.
PCB - A2 connector, is 230V
across terminals 5 & 7
E
Check and correct if necessary
1. Electrical and pressure tube connections
2. Blockage of pressure tubes
3. Restriction in flue
4. Venturi
F
NO
Gas at burner
NO
YES
NO
If pump jammed, release
NO
NO
NO
YES
NO
NO
YES
NO
NO
Ensure gas is on and purged
PCB - A1 connector has 230V AC
across terminals 2 & 4
NO
neon flashing
NO
Replace PCB
Check electrical supply
Replace fuse
Check wiring
Replace selector
Replace pump
Replace PCB
Re-pressurise system
Open the automatic air vent
Replace diaphragm
Flow valve rod obstructed
Replace microswitch
YES
Replace sensor
Fan jammed or faulty winding
Replace PCB
Replace air
pressure switch
YES
Replace gas valve
YES
Turn selector switch
to reset position
14.0 Fault Finding
NO
neon
illuminated
YES
Replace fan
R
Replace PCB
41
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