Impinger II – Advantage Digital Express Service Manual - International
11
Oven will not heat
Main fan
If not operating, refer to “Oven fan will not run”.
Control transformer
Check for supply voltage to the primary of control
transformer. If no voltage is present, trace wiring back
to oven fan switch. If voltage is present, check for
24VAC at transformer secondary. If there is primary
voltage, but no secondary voltage, replace control
transformer.
Air pressure switch
Check air switch terminals for supply voltage to
terminals “NO” and “COM”. If voltage is present on one
side only, check for air tube blockage or misalignment.
If these are okay, adjust air pressure switch or replace if
necessary.
Oven control
Check for 24VAC supply to oven control. If no voltage is
present, trace wiring back to control transformer. Check
for supply voltage to oven control. If no voltage is
present, trace wiring back to oven fan switch. If voltage
is present, check for a read-out on the display. If there
is no read-out on the oven display, replace oven
display. If there is a read-out on the oven control, set
the control to maximum temperature (see Installation
operation manual for temperature adjustment). With the
control at maximum temperature, check for supply
voltage to the mercury contactor. If there is voltage at
the contactors, proceed to “Mercury contactor” for next
check. If there is no voltage at the mercury contactor,
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 oven control reads “PROBE
FAIL” this indicates that the thermocouple has failed or
become disconnected from the oven control.
Thermocouple
Check to see that the thermocouple is securely
connected to the oven control. If the thermocouple is
connected to the oven control, and the display 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
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 supply
voltage output to the contactor, replace the oven
control. If there is supply voltage output to the
contactor, proceed.
S.S. Relays
Check for supply voltage to the contactor coil. If voltage
is present and the contactor will not activate, replace
the contactor Also check each contactor for high
voltage input and output.
Heating element(s)
Check the Amp draw on each power leg for proper
load. Check the specification plate for rating
information. If the Amp draw is high or low, check the
