Garland 40 Series Technical Reference Manual - page 57
Part # GCTRM Rev 3 (12/10/09)
Page 57
3/8" TO 1/2"
Pilot
Thermocouple
If, while following the proper lighting procedures, the
magnet cannot be made to “HOLD”, inspect the pilot fl ame
for proper size and adjustment (see pilot burner adjustment).
If the magnet will still not hold, make the following checks.
Closed Circuit Test
(Totestmagnet&thermocoupleasacomplete
unit)
To make the closed circuit test, remove the thermocouple
lead from the magnet contact. Place an adapter (Robertshaw
Part #75036) in the magnet contact and turn the
thermocouple into the adapter fi nger tight. Connect millivolt
leads to the adapter and thermocouple lead as shown in
fi gure “A”.
FigureA
BLACK
RED
Terminal Boss
Adapter
Thermocouple Tube
PN 4526299
IntheSitControl,insertametricM9adapterinthemagnet
contacttocompletethesafetyvalvecheckasshownin
FigureB .
FigureB
1. Make sure the thermocouple is properly inserted into
the pilot housing, and has no play. Also check gas tubing
connection at the pilot and tighten if loose.
2. Re-light the pilot, and read the meter after the pilot
has been burning for three minutes. If the pilot will not
continue burning, depress and hold the temperature
knob to manually open the SIT safety valve to check
the thermocouple output for this closed circuit check.
If insuffi cient (normal output for closed circuit is
8-14 millivolts), and under 7 millivolts, replace the
thermocouple. If the millivolt reading is above 7 mV, and
the safety magnet does not hold, replace the valve.
3. If the closed circuit mV reading is the same as the open
circuit reading, the coil is electrically open, and the valve
must be replaced.
4. Check for drop out time which should occur within 60
seconds and at approximately 2 mV since the pilot was
out.
5. Relight the pilot and turn the main burner On. As the
oven heats up, it is normal to see a slight decrease of
millivolts.
Thermocouples
SIT
Robertshaw
Orkli
mV
Closed
Circuit
8-14
10-15
8-14
Open
Circuit
18-28
20-30
24-30
Drop
out
2
5
2