Lincoln 1450, 1451 service manual With Power on and Thermocouple

		the display, replace oven control. If there is a read-out
		on the control, set the control to maximum temperature
		(see Installation operations manual for temperature
		adjustment). With the control set at maximum
		temperature, check for 120VAC at the temperature
		regulation valve. If there is voltage at the temperature
		regulation valve, proceed to “Temperature regulation
		valve” for next check. If there is no voltage at the
		temperature regulation valve, trace wiring back to the
		oven control. If there is no voltage output at the oven
		control, check the read-out on the oven control. If the
		control reads “PROBE FAIL”, this indicates that the
		thermocouple has failed or become disconnected from
		the oven control.
	Thermocouple	Check to be sure that the thermocouple is securely
		connected to the oven control. If the thermocouple is
		connected to the oven control, and the control indicates
		“PROBE FAIL”, disconnect the thermocouple from the
		oven control and measure the resistance of the
		thermocouple. The thermocouple should read approx.
		11Ω. If these readings are not achieved, replace the
		thermocouple. If these readings are correct, proceed.
	Oven control	If the thermocouple checks good, but the oven control
		display indicates that there is a thermocouple failure,
		replace the oven control. If the oven control indicates a
		temperature reading, but the oven will not heat,
		proceed.
	Thermocouple	WITH POWER ON AND THERMOCOUPLE
		ATTACHED TO THE OVEN CONTROL: Measure the
		DC millivolt output of the thermocouple. Refer to the
		thermocouple chart (located in the “Removal” section of
		the manual) for proper millivolt readings. If these
		readings are not achieved, replace thermocouple.
	Oven control	If the thermocouple checks good, but there is no
		120VAC output to the temperature regulation valve,
		replace the oven control. If there is 120VAC output to
		the temperature regulation valve, proceed.
	Temperature regulation valve	Check for 120VAC supplied to the temperature
		regulation valve. If voltage is present, listen for valve to
		open and close. Also check for opens or shorts in the
		operating coil. Replace temperature regulation valve as
		needed.
Intermittent heating	Thermal/overload of main fan	The main fan motor and burner blower motor are
	and burner blower motors	equipped with internal thermal protection and will cease
		to operate if overheating occurs. As the motors
		overheat and then cool, this will cause the heating
		system to cycle on and off intermittently. Improper
		ventilation or lack of preventive maintenance may
		cause this problem. Also, most of the problems listed
		under “Oven will not heat” can cause intermittent
		failure.
Conveyor will not run	Incoming power supply	Check circuit breaker, reset if required. Check power
		plug to be sure it is firmly in receptacle. Measure
		incoming power, call power co. if needed.
	Fuse, 10 Amp	Check, replace if necessary.
	Fuse holder	Check, replace if necessary.
	Switch, oven power	Check for 120VAC supply to switch. If no voltage is
		present, trace wiring back to fuse holder. Check
		continuity between switch terminals. Replace switch as
		needed.

6 Impinger I – 1450 Series Service Manual - Domestic