Lincoln 1450 - Manual (Page 5)

Impinger I – 1450 Series Service Manual - Domestic 5
not running, check for opens, shorts or grounds.
WITH POWER OFF: Turn motor to check for locked
rotor. Replace burner blower motor as needed.
Burner transformer Check for 120VAC supplied to primary of burner
transformer. If no voltage is present, trace wiring back
to centrifugal switch of main fan motor. If voltage is
present, check for 24VAC supply at transformer
secondary. If there is primary voltage but no secondary
voltage, replace burner transformer.
Centrifugal switch of burner
blower motor
Check for 24VAC at motor connector, wire #19 (input to
centrifugal switch) to neutral. If no voltage is present,
trace wiring back to burner transformer. If voltage is
present, check for 24VAC at wire #20 (output of
centrifugal switch) to neutral. If no voltage is present at
wire #20 and motor is running, replace burner blower
motor.
Ignition control Check for 24VAC supply to the ignition control. If no
voltage is present, trace wiring back to centrifugal
switch of burner blower motor. If voltage is present,
check for 24VAC at pin #3 and ground (pilot valve).
NOTE: The Honeywell ignition control has a 30 second
pre-purge (time delay) built in. If voltage is not present,
replace ignition control. If the pilot valve is energized,
check to see that the high voltage igniter circuit is also
energized. To check, disconnect the igniter lead from
the ignition control.
No pilot flame If the ignition control is supplied with 24Vac and the
pilot valve (internal to valve assembly) and igniter
circuits are energized, visually check for pilot flame.
This may be done by opening the small inspection door
on the end of the burner, or by opening the main oven
door and looking under the lower finger housings on
the right side of the oven. If no pilot flame is visible,
check the pilot shut-off valve.
Pilot shut-off valve Check to see that the pilot shut-off valve is open (shut-
off valve is located between valve assembly and
burner).
Pilot tube Check for gas pressure at the pilot tube. Disconnect
pilot tube at burner and connect a manometer to pilot
tube. If no gas pressure is present during ignition,
check for blockage in pilot tube or pilot shut-off valve. If
these are clear, and there is gas supplied to the oven,
replace the gas valve.
Pilot orifice If there is gas pressure at the pilot tube, check the pilot
orifice for obstructions. Replace as needed.
Burner igniter Check the burner igniter head for any obstructions, also
check for frayed or broken wire. Check spark gap (gap
should be .100 to .125 inch). If there is visible damage,
replace burner igniter.
NOTE: Flame should be on
at this time
Pilot flame, but no
main flame
Control transformer Check for 120VAC supply to the primary of the control
transformer. If no voltage is present, trace wiring back
to the oven power switch. If voltage is present, check
foe 24VAC at the transformer secondary. If there is
primary voltage, but no secondary voltage, replace
control transformer.
Oven control Check for 24VAC supply to oven control. If no voltage
is present, trace wiring back to control transformer. If
24VAC is present, check for a read-out on the display.
If there is 24VAC supplied, but there is no read-out on