A_GC_SM_HDGASCOUNTERSERV_GT-UT-SERIES (Rev 1) Page 23
Griddle Adjustments — SIT Thermostat (continued)
Closed Circuit Test (To test magnet & thermostat as a complete unit)
BLACK
RED
Terminal Boss
Adapter
Thermocouple Tube
PN 4526299
In the Sit Control, insert a metric M9 adapter in the magnet
contact to complete the safety valve check as shown
To perform the closed circuit test, remove the thermocouple lead from
the magnet contact.
Place an adapter in the magnet contact and turn the thermocouple
into the adapter finger tight. Connect millivolt leads to the adapter
and thermocouple lead as shown.
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 insufficient (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. Re-light the pilot and turn on the main burner. As the griddle heats up, it is normal to see a slight decrease in
millivolts.
Open Circuit Test
1. Disconnect the thermocouple from the safety valve.
2. Attach the thermocouple to the millivolt test instrument.
3. Heat the sensor end of the thermocouple at the pilot flame or similar flame characteristics, monitoring the
millivolt meter
4. If the millivolt reading is below 18 millivolts, replace the thermocouple
Note: The SIT thermocouple open circuit voltage will be approximately 18-28 millivolts
SIT Thermocouple
mV
Closed Circuit 8-14
Open Circuit 18-28
Drop Out 2
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General