Lincoln Impinger Conveyor Ovens 1100 Series - Manual (Page 43)

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
contactor 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
as follows:
200V - 24.5 ohms approximately
Oven heats with switch off Mercury Contactor The mercury contactor has probably
malfunctioned in the closed position.
If there is no voltage to the operating
coil, but there is high voltage at the
contactor output, replace the mercury
contactor.
Intermittent Heating Thermal/Overload The main fan motor is equipped with internal
of motor thermal protection and will cease to
operate if overheating occurs. If the
motor overheats and then cools, this will
cause the oven to cycle on and off
intermittently. This may be caused by
improper ventilation or preventative
maintenance. Also, most of the problems
listed under “Oven will not heat” can
cause intermittent failure.
Conveyor will not run REFER TO PAGE 31
S/N 2011383 and above REFER TO PAGE 45
Conveyor speed varying or intermittent REFER TO PAGE 32
S/N 2011383 and above REFER TO PAGE 45
Time/Temp. Display inoperative REFER TO PAGE 33
Impinger II - 1100 Series Service Manual - International 43