Lincoln Impinger Conveyor Ovens 1633-000-EA - Manual (Page 9)

Low Profile –1600 Series Advantage Digital Service Manual -–Int’l 9
Oven control Check for 24VAC supply to control. If no voltage is
present, trace wiring back to control transformer. If
24VAC is present, check for a read-out on the control
display. If there is 24VAC supplied, but there is no
read-out on the control display, replace the 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 line voltage 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 control. If the control reads “LP FAIL” or “RP
FAIL”, this indicates that the thermocouple has failed
or has become disconnected from the control. “LP
FAIL” indicates a problem with the left thermocouple
probe, and “RP FAIL” indicates a problem with the
right thermocouple probe.
Thermocouple probe 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 “LP FAIL” or “RP FAIL”, disconnect the
thermocouple from the oven control and measure the
resistance of the thermocouple. The left thermocouple
should read approx. 21
Ω. The right 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
voltage output to the temperature regulation valve,
replace the oven control. If there is voltage output to
the temperature regulation valve, proceed.
Temperature regulation valve Check for line voltage supplied to the temperature
regulation valve. If no voltage is present, trace wiring
back to the oven control. If voltage is present, listen
for the valve to open and close. Also check for opens
or shorts in the operating coil. Replace temperature
regulation valve as needed.