User Manual

38
4000123944-2
18 Fault Finding
COMPONENT NORMAL MEASURE CHECK
Gas control valve Under demand during ignition sparks: If 0 Volt: the gas control valve
Resistance of coil 116Ω 24V dc for 1 to 2 seconds, then is not faulty.
12Vdc (constant) at the gas control If 24 Volts and then 12 Volts
valve electrical connection. but no gas at the burner:
Check if the gas control valve is
stuck. If not, check the
adjustment valve.
Adjustment valve Close the gas inlet: If the valve does not move:
(step motor) Dismantle the step motor (screw not Check the connections at both
sealed in). Trigger a demand and check motor and control board (PCB).
that the valve opens during the ignition. Change the motor. Replace the
control board (PCB).
Three way valve. When heating is on: If voltages are different:
Electrical supply to motor 230V ac between 1 and 2 of the motor. Connections.
0Ω between 1 and 3. About 25V ac to 35V ac between 2 and 3. Control board (PCB).
9.6kΩ between 1 and 2. When hot water is on: Three way valve lead.
9.6kΩ between 1 and 3. 230V ac between 2 and 3 of the motor. 3 2 1
(1, 2 and 3 marked on About 25V ac to 35V ac between 1 and 2.
the motor).
Thrust action of the motor. Unfasten the clip (YES, no risk of water If electrical supply is OK.
(remove gas control valve leak), pull out the motor and leave it but the spindle does not move
before testing) plugged in. Replace the motor, or replace
When hot water is on: the spindle should the control board (PCB).
pull in. When heating is on : the spindle
should push out.
Domestic water flow To test: Use a new detector and
connect it electrically in place of
the faulty one . Blow through to
simulate a demand for water.
COMPONENT TESTING DATA