Graco 257500, 258699 Terminal Connections, Connections Contacts Reading Diagnosis

Kettle Gas Safety Valve, Kettle Temperature Control, and Kettle Thermopile Diagnosis

Kettle Gas Safety Valve,

Kettle Temperature Control, and

Kettle Thermopile Diagnosis

The gas safety valve, temperature control and thermo- pile can be checked by using a millivolt meter. Before checking, make certain all electrical connections are clean and tight.

Terminal Connections

3

TH

TP TH

1

TP

Connect millivolt meter to appropriate terminals (see					ti14524a	2
Terminal Connections).
			Status of
			Temperature	Desired
	Part(s) to Be	Terminal	Control	Meter
Step	Checked	Connections	Contacts	Reading	Diagnosis
1	Gas safety	2 and 3	Closed	Greater than	If mV reading > 100 mV and the automatic valve (main
	valve			100 mV	burners) does not come on, replace the gas safety valve.
					If mV reading < 100mV, proceed with diagnostic steps 2
					and 3.
2	Temperature	1 and 2	Closed	Less than	If reading > 80 mV:
	control			80 mV	• Clean and tighten electrical connections at tempera-
					ture control and gas safety valve.
					• Check valve to make sure wires are in good condi-
					tion. Replace as required.
					• Rapidly change temperature setting on temperature
					control to see if cycling cleans the contacts.
					If the preceding fails to give mV reading < 80 mV, replace
					temperature control.
3	Gas safety	1 and 2	Open	Greater than	If mV reading < 325 mV:
	valve magnet			325 mV	• Clean and tighten all electrical connections.
	and
					• Adjust pilot burner to increase millivolt output (see
	thermopile
					page 11).
					If the preceding fails to give mV reading > 325 mV, replace
					thermopile.
					Check valve magnet after obtaining correct mV output for
					thermopile:
					• Ignite pilot burner only and allow the mV reading to
					stabilize.
					• Shut pilot burner (turn gas safety valve knob OFF).
					Note the mV reading where magnet drops out.
					If magnet unlocks at mV reading < 120 mV, the magnet is
					OK. NOTE: When magnet unlocks a click can be heard
					and mV reading may fluctuate slightly.

313879B 5