Lincoln Impringer Conveyor Oven 1200 - Manual (Page 50)

Impinger I -–1000 Series Service Manual - International 50
Main Flame will not
stay lit Flame Monitor (There should be a visible main flame at this time.)
To check for flame monitor operation, connect a
digital volt meter (capable of measuring D.C. micro
amperes) between the flame sensor and terminal
#15 on the flame monitor. The flame monitor
requires a minimum of 4 micro amp. D.C. for proof
of flame. If these readings are not achieved,
replace sensor assembly. Also check for any type
of damage to flame sensor wire and connections.
If the reading is above the minimum required, and
the flame monitor will not supply 220 VAC to the
relay coil, replace the flame monitor.
Intermittent Heating As Follows Both the main fan motor and burner blower motor
are equipped with thermal protection and will cease
to operate if overheating occurs. This can cause
the units to cycle on and of intermittently. This may
be caused by improper ventilation. Also, most of
the problems listed under "oven will not heat" can
cause intermittent failure.
Conveyor Switch Check for 120 VAC to conveyor switch. If no
voltage is present, trace wiring back to the power
supply. WITH POWER OFF: Check continuity
between switch terminals
Conveyor Fuse(3A) Check, replace if necessary.
Fuseholder Check, replace if necessary.
Conveyor Control Check for 120 VAC supply to primary (Stepper)
Transformer of transformer, if voltage is not
present, trace wiring back to the fuseholder. If
voltage is present, check for output voltage from
the transformer secondary. NOTE: this control
transformer outputs (2) secondary voltages: Red
Leads 29 VAC Brown Leads 10 VAC. If BOTH
secondary voltages are not present, replace the
transformer.
Conveyor will not run
Speed Adjustment
Potentiometer This is a 0 to 50K ohm, 10 turn potentiometer.
WITH POWER OFF: remove the 3 pin
potentiometer cable plug from the motor control
board. With a digital multimeter, check the ohm
reading across the red lead to the black lead, this
reading should be 50K ohms ± 5% as the
potentiometer is rotated through its 10 turn rotation.
Place the meter leads on the red lead and white
lead. Rotating the potentiometer slowly, from low to
high, the meter should show an even transition
from 0 to 50K ohms ± 5% through the 10 turn
rotation of the potentiometer. There should be no
dead or open spots through the 10 turns of the
potentiometer. Check all three leads to ground.
There should be no continuity to ground. If any of
the above checks fail, replace the potentiometer.
Conveyor Motor(Stepper)
Control
NOTE: if the conveyor drive motor becomes
jammed or begins to run at an uncontrolled speed,
the conveyor motor will stop running. To reset, turn
off the conveyor switch, wait 30 seconds, turn the
conveyor switch on. If the motor does not run after
attempting re-set, check for 2 to 29 VAC across the
motor terminals 1 to 2 and 3 to 5 on, the conveyor
motor control. If voltage is not present at both sets
of terminals, replace control.