25
221954D
Is there 230V~ between SL and
N and between L and N ?
Diagram 11.2
Is neon 1 lit?
YES
YES
YES
NO
Correct power supply problem.
NO
YES
Replace thermostat.
NO
YES
NO
Is neon 3 lit?
Is there 230V~ between
"N/C" on air pressure switch and N ?
YES
Check yellow cable between printed circuit board
and air pressure switch.
If satisfactory replace printed circuit board.
YES
NO
Is there 230V~ between "C" on air pressure
switch and N ?
Replace air pressure switch.
Does fan run?
YES
NO
NO
YES
Replace fan.
YES
Replace printed circuit board.
Does fan Hunt?
NO
Inspect air tubes for leaks, kinks and correct fitting. If
satisfactory replace faulty air pressure switch.
NO
Is there 230V~between "N/O" on air
pressure switch and N ?
YES
NO
NO
Is there 230V~ between yellow connection on
overheat device and N ?
Is there 230V~ between motor connections on fan?
Isolate electrical supply test fan harness continuity.
If satisfactory replace printed circuit board.
Before detailed checking of electrical components ensure that remote controls are calling for heat. Check the gas supply is free of obstructions and purged of air. Check the
overheat cutoff has not operated. For fully pumped systems only. Isolate the electrical supply and physically check ALL cables, connections and the printed circuit board fuse.
Check the air tubes to the air pressure switch. Switch on the electrical supply and check for correct polarity. Turn the control thermostat to its maximum setting. Also check fuses.
Check overheat reset.
If satisfactory replace overheat device.
Is neon 2 lit?
NO
Is there 230V~ between K1 and N ?
YES
YES
Check 0.2 Bar of water pressure is available at
boiler, If ok, Replace water pressure switch.
NO
Is there 230V~
between "N/C" on thermostat and N ?
NO
NO
Inspect electrode lead /connection for poor contact.
Check electrical supply polarity and correct if necessary.
If satisfactory replace printed circuit board.
With pilot lit does spark stop?
NO
Replace main solenoid
YES
Replace multi-functional control.
YES
Is Neon 4 lit?
NO
Does main burner light?
System satisfactory
YES
NO
YES
YES
Is there a spark at pilot burner?
Check lead continuity and inspect electrode and
lead for damage.
Check for pilot jet blockage, incorrect electrode
adjustment isolate supply. Remove plug from
multifunctional control. Check continuity of pilot
solenoid between EV1 and COM, continuity OK?
Does pilot light?
NO
Replace multifunctional
control
Replace pilot
solenoid.
NO
YES
Isolate supply. Remove plug from the
multifunctional control. Check continuity of
main solenoid between EV2 and COM.
Continuity OK?
YES
11 Fault Finding
M A I N T E R M I N A L S T R I P
C O N T R O L T H E R M O S T A T
11.1 Electrical
IMPORTANT:
On completion of the Service/Fault Finding task which has required the breaking and remaking of the electrical
connections, the earth continuity, polarity and short circuit and resistance to earth checks must be repeated using a suitable
multimeter.
Refer to diagrams 11.1 to 11.5 for the relevant fault finding and wiring information.