5
Trouble-shooting
17
© Moffat Ltd, January 2007
Revision 1/
Blue Seal Evolution Series Gas Griddles
5.2 Fault diagnosis
Short in high tension lead
If repeated sparking of the piezo shows
intermittent sparking at the electrode, then the
lead should be traced to find area of short. This
can normally be visually seen as the spark arcs.
If the lead is shorting the best solution is to
replace it, as the electrical insulation strength of
the lead may have deteriorated.
If the spark arc can be seen at the electrode
insulator at the pilot burner instead of at the
electrode tip, then the insulator probably has a
fracture and should be replaced.
Piezo ignitor faulty
If no spark at all can be generated, remove piezo
ignitor and hold close to the hob body, depress
piezo ignitor and if a spark cannot be generated
to hob body the piezo ignitor is faulty and should
be replaced.
5.2.1 Pilot goes out when pilot
knob is released
5.2.2 Piezo ignitor not sparking
Pilot flame too small
If pilot can be lit but the flame is too small to im-
pinge on the thermocouple, then check the gas
pressure. If ok, remove pilot injector from pilot
burner and check for blockages and/or correct
size.
Thermocouple faulty
Inspect thermocouple for build-up of carbon or
food deposits on the tip. Clean off any deposits,
taking care not to scratch off the aluminium
coating on the thermocouple.
Check that the thermocouple tip is in the flame
zone of the pilot burner. When the burner is lit,
the flame should impinge on the top 5mm of the
thermocouple tip.
NOTE: The thermocouple should not touch the
burner.
Check thermocouple connection to gas
control is firm (loose connections will cause resis-
tance in millivolt circuit and result in pilot out-
age).
If connection is OK, then disconnect the
thermocouple from the gas control, light the pilot,
and whilst holding the control knob in, measure
voltage between the thermocouple internal wire
(refer figure 5.2.1) and earth (e.g. the body of
the gas control). This should read approximately
30mV. If this reading is less than 10mV then the
thermocouple is faulty—replace.
Figure 5.2.1
Tip
Internal Wire
Gas magnet faulty
If thermocouple milli-voltage is above 10mV, and
the pilot still will not hold, then the gas magnet is
faulty - replace.
NOTE: Oven valves will require replacement if
the gas magnet is faulty.
