-24-
Revision 7/F3527
©
Moffat Ltd, November 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.
Overtemp tripped (UK units only)
Open the control panel. Check for power at
terminal 1 of power switch. If power at
terminal 1 then overtemp is ok, refer “power
switch faulty” (below).
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.
Remove the front service panel and turn the
thermostat on to initiate a heating cycle. Look
through the round viewing holes next to the
electrode assembly, and look for spark
generation at the end of the electrodes. If
spark is heard but not visible,
turn off/isolate
gas supply
, and remove electrode assembly.
With gas supply off, turn thermostat back on
again with electrode assembly suspended in
air. 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 the
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 - refer section 11.3
(select appropriate assembly type).
NOTE:
Use drill bits to gauge spark gap
settings
With spark system correctly checked,
re-install into burner box and re-check
operation.
If fault persists it is possible that the
electrodes are out of position in relation to the
burner flame. Adjustment may be necessary
to set the electrode gap to the correct position
(refer to following diagram).
WARNING: OVERTEMP BUTTON IS
LIVE. ISOLATE UNIT FROM POWER
SUPPLY BEFORE RESETTING.
If no power to terminal 1, inspect overtemp
reset button (at rear of control cavity). If the
overtemp has tripped then the reset button will
have popped out, and will click when
depressed. If the overtemp resets then a fault
exists with the temperature control of the oven
(check calibration, refer 6.4.2, or overtemp
calibration is faulty, refer 6.4.3).
If the overtemp button cannot be reset, and
the oven temperature is below 300°C
(- overtemp will not reset above 300°C), then
the overtemp is faulty - replace.
Power switch faulty
Check if power switch latches. If the switch
does not latch, then switch is faulty—replace.
With switch latched, check voltage across
terminal one to terminal three or four. If there
is no voltage, check for fault in wiring.
Check voltage across terminal two to terminal
three or four. If there is no voltage, then
switch is faulty—replace.
NOTE:
When power switch is latched, it
should illuminate if it is operating
correctly.
