Lincoln 1628-000-A - Manual (Page 7)

Low Profile – 1600 Series Adv Dig Electric S.M. – Int’l 7
Intermittent heating Thermal overload of main
fan motor(s)
The main fan motors are equipped with internal
thermal protection and will cease to operate if
overheating occurs. As the motors overheat and then
cool, this will cause the units to cycle on and off
intermittently. Improper ventilation or lack of
preventive maintenance may cause this problem.
Also, most of the problems listed under “Oven will not
heat” can cause intermittent failure.
Power supply Check for supply voltage at terminals L1 and L2. If
voltage is not present check breakers.
Power switch Check continuity between switch terminals. Replace
switch as needed.
Fuse, 10 Amp. Check and/or replace.
Fuse holder Check and/or replace.
Hi-limit thermostat(s),
control box
Check for voltage on both sides of the switch.
Terminals are normally closed. If open, reset and test
for proper operation. If thermostat will not hold, and
the control box temperature is not exceeding 140
° F
(60 ° C), replace thermostat.
Relay, oven control Check for line voltage to the relay coil. If voltage is not
present, trace wiring back to the hi-limit thermostat. If
voltage is present, check to insure contacts are
closing. Replace relay as needed.
Control transformer Check for line voltage supply to the primary of the
control transformer. If no voltage is present, trace
wiring back to the oven power relay. If voltage is
present, check for 24VAC at the transformer
secondary. If there is primary voltage, but no
secondary voltage, replace control transformer.
Conveyor motor Check for line voltage supply to the conveyor motor at
wire #28 to neutral. If no voltage is present, trace
wiring back to the oven power relay. If voltage is
present and the motor will not run, check the motor
windings for opens or shorts.
WITH POWER OFF: Check the motor windings as
follows:
Grey to black - 116 ohms
Grey to brown - 116 ohms
Brown to black - 230 ohms
Conveyor will not
run
Capacitor, conveyor motor Check for shorts or grounds. Replace capacitor as
needed.
WARNING: Capacitor has a stored charge, discharge
before testing.
Switch, conveyor reversing Check continuity between switch terminals, Replace
switch as needed.
Oven control If there is supply voltage to the motor. And the motor,
capacitor, and reversing switch check good, replace
the oven control.
NOTE: Display will indicate
“Belt jam”
Conveyor motor
runs, but there is
no speed display Oven control Check for output voltage from the oven control to hall
effect sensor (sensor is located in conveyor motor).
Measure voltage at the motor connector, red wire and
yellow wire. Voltage should be approx. 10VDC. If no
voltage is present, trace wiring back to oven control. If
there is no voltage present at the oven control,
replace the oven control.