Lincoln Impinger Conveyor Ovens 1100 Series - Manual (Page 35)

Switch, Heat With switch on, check for 120 VAC on both terminals
to neutral. Replace if defective.
Air Pressure Switch This normally open switch should close when the
main fan is activated. Adjust if necessary (Refer to
Section D). Replace if defective.
Fuse, 3 Amp Check, replace if necessary.
Fuseholder Check, replace if necessary.
Temperature Control Check for 120 VAC supply at terminal #11 to neutral
on temperature control. If no voltage is present, trace
wiring back to 3 amp fuse. Turn the temperature
adjustment knob to maximum temperature position
and check for 120 VAC at the load terminal (#9) and
neutral. If 120 VAC is present and unit is not heat
-ing, refer to “Mercury Contactor” for next check.
If 120 VAC is not present, proceed.
Thermocouple Probe WITH POWER ON AND THERMOCOUPLE
LEADS ATTACHED TO THE TEMPERATURE
CONTROL BOARD: measure D. C. millivolt output of
these leads. Refer to thermocouple chart in Section
D for proper readings. If these readings are not
achieved, replace thermocouple.
Temperature Control WITH POWER OFF: remove the
Potentiometer potentiometer leads from the
temperature control board and measure ohms from
black to white leads. The reading should be from
approximately 0 to 2.5k ohms as the dial of the
potentiometer is turned throughout its full rotation.
From black to red leads, the reading should be
approximately 2.5k ohms (constant) throughout the
full rotation of the dial. If these readings are not
achieved, replace potentiometer. If the thermocouple
probe and the control potentiometer check good,
then the problem is usually with the temperature
control board.
Mercury Contactor Check for 120 VAC to the contactor coil. If voltage is
present and contact will not activate, replace the
contactor.Also, check each contactor for proper
high voltage input and output.
Heater Elements Check the Amp. draw on each hot leg for
proper load.
Check the specifications plate for rating
information.
If the Amp. draw is low or high, check
the individual elements for opens,
shorts, and proper resistance.
WITH POWER OFF: To check resistance
of the elements, remove all leads from
the elements and use an accurate digital
VOM. The element resistance should be
Impinger II - 1100 Series Service Manual - International 35