Lincoln 1450 - Manual (Page 6)

Impinger I – 1450 Series Service Manual - Domestic 6
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.
11
Ω. 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
and burner blower motors
The main fan motor and burner blower motor are
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.