Filter
Top Products
-20-
Revision 4/F3576 © Moffat Ltd, December 2004
6.1 FAULT DIAGNOSIS
Incorrect electrical supply
Check that the voltage across phase and
neutral (L1 and L2) terminals of terminal block
is the voltage as stated on the unit’s electrical
rating plate.
If incorrect, check electrical connection of
supply wiring and / or check electrical supply.
Power switch faulty
With switch on, check voltage at terminal 1 of
switch. If there is no voltage, check for fault in
wiring. Check voltage at terminal 2. If there is
no voltage then the switch is faulty - replace.
6.1.1 OVEN DOES NOT OPERATE / START
6.1.2 NO HEAT/BURNER NOT WORKING
Burner ignition spark not working
A faulty spark system is one that does not
light the burner at all. If the burner is being lit
temporarily, but fails to stay alight, then the
problem is in the flame sensing, not spark
ignition. Refer “Burner flame not being
sensed” (following).
Firstly determine if spark is being generated.
Gain access to the oven burners (refer 6.2.6).
Turn off the gas supply, and with electrical
supply turned on, turn the thermostat on to
initiate a heating cycle. Look for spark
generation at the end of the electrodes
located above the right hand burner. A
correctly functioning ignition system should
show sparking visible across spark and earth
rod ends. If spark is not seen at electrode
ends, or sparking is erratic, this indicates that
there is a high voltage short/breakdown
between the ignition box and electrode ends.
Possible causes to investigate are as follows,
inspect and correct as necessary:
- Spark gap too large (see the following
section).
- Cracked spark rod ceramic, or carbon
build-up.
- HT leads to spark electrode and earth
broken/deteriorated.
- HT leads between ignition electrodes and
ignition control box broken/deteriorated.
- No spark from ignition box, refer ignition
box faulty.
Spark gap setting
With spark electrode assembly removed,
inspect spark rod and earth electrode settings,
and spark gap settings.
Between SPARK and EARTH (centre) 3-5mm
Between EARTH and main burner 7-10mm
Between SENSOR and EARTH 10-12mm
Between SENSOR and main burner 7-10mm
NOTE:
Use drill bits to gauge spark gap
settings
With spark system correctly checked,
re-check operation.
Burner flame not being sensed
The flame sensing electrode requires correct
positioning in the burner flame. Incorrect gas
pressures, types, injector sizes, etc will affect
correct operation of flame sensing system.
Ensure that these are checked and correct
before carrying out further investigation. Also,
an incorrectly earthed/grounded appliance will
cause faults with the flame sensing system.
Always ensure a correct earth/ground
connection on the appliance connection and
supply.
If the flame rod is touching the burner then
there is a short circuit to earth, and this will
cause the ignition control to not sense the
flame correctly. This fault would normally be
indicated by a burner that fails to stay alight
during operation, or during an ignition attempt
the sparking continues after the burner is lit.
The flame rod should be adjusted to be clear
of the burner by 7-10mm.
Always inspect the connection lead from the
flame rod to the ignition box for deterioration,
bad connections, or insulation breakdown.
Ignition box faulty
The direct spark ignition control boxes used
on G1100’s are operated from direct voltage
supply from the thermostat / hold thermostat
circuit.
Correct ignition box operation should result in
ignition box commencing spark at ignition
electrodes and opening gas valve to ignite
burners, then maintain burner on after
successful ignition.
If no spark generated or heard, check that
ignition box has correct supply voltage (when
thermostat in ON).