Lincoln Series 1200 FlameFor ovens with, Mechanical, Thermostat, Electronic, Temperature Control

	Burner Ignitor	Check the burner ignitor head for any obstructions,
		also check for frayed or broken wire, any type of
		damage to spark gap (.100 in. 2.5 mm) If there is
		visible damage, replace ignitor assembly.
Pilot flame but no main	Spark Ignitor (Flame Sensor)	(There should be a visible pilot flame at this time).
flame		NOTE: The Honeywell Ignition Control uses the
		spark ignitor as the flame sensor. If spark
		continues, check for proper ground connections at
		Ignition Control. Check pilot orifice for any partial
		blockage. If the above checks OK, replace ignition
		control. If spark stops when pilot is lit, check for 24
		VAC across M.V. - M.V/ P.V. terminals, if voltage is
		not present, replace ignition control. If voltage is
		present at terminals M.V. - M.V./P.V., the indicator
		light on the control panel should be on, verify that
		the main valve has opened, connect manometer to
		manifold gas pressure tap (located on the back
		side of the gas valve). If no gas is present, replace
		gas valve.
Red Indicator Light is	Temperature Control Valve	Check for gas supply at temperaturecontrol. Check
on, but no main	(Robert Shaw)	for temperature control set above 300°F.
flame(For ovens with	Main Orifice	Check for blockage of main orifice. If there is no
mechanical		blockage to the main orifice, replace the
thermostat)		temperature control.
(For ovens with	Temperature Control	Check for 120 VAC across L1 and L2on
Electronic	Potentiometer	temperature control board. Potentiometer (1000
Temperature Control)		ohm,1 turn) WITH POWER OFF: check ohms
		across red and black leads, the ohm reading
		should be 0 to1000 ohms as the dial is turned.
		From green to red, the reading should be 1000
		ohms steady throughout the full turn of the dial.
NOTE: Ovens S/N Q18037 and above, the potentiometer is internal to temperature control. Proceed to next
component.
	Thermocouple Probe	Remove thermocouple leads from the temperature
		control board, and measure the millivolt output of
		these leads. Refer to chart on page 59 in the
		adjustment section for proper readings.
	Temperature Control	Turn temperature control dial to full "on" position.
		Measure for 120 VAC across terminals "N.O." and
		"L2", if voltage is not present; replace control.
	Solenoid Valve	If voltage is present at terminals "N.O." and "L2",
		check for voltage at solenoid valve. If voltage is
		present, listen for valve to open and close. Also,
		check for opens and shorts in coil. If solenoid valve
		is defective, replace
Intermittent Heating		Both the main fan motor and burner blower motor
		are equipped with thermo-protection and will cease
		to operate when not cooled properly. This can
		cause the units to cycle on and off intermittently.
		Also, most of the problems listed under "oven will
		not heat" can cause intermittent failures.

For continuing intermittent problems, a series of test lights may be made and installed in

the ovens. The lights will allow the customer to advise the service technician a trouble code when the oven fails.

The lights should be connected in the following manner:
Light#l attached in 120VAC line after Air Pressure Switch.
Light#2 attached after 120VAC contacts of Burner Motor Relay (or, refer to Bulletin #028
for Relay Removal).
Light#3 in 24VAC Burner Transformer Secondary.
Impinger I -–1000 Series Service Manual - International	29