Impinger 3270 Service Manual – Dom & Int’l
15
Oven will not heat
(continued)
Air Pressure Switch of
Burner Blower Motor
Check for air pressure switch to be switching from “NC” to
“NO”. Check for air tube blockage or misalignment. Adjust
air pressure switch. If the above fails, replace air pressure
switch.
Ignition Control
A pre-purge time of 30 to 60 seconds occurs after burner
blower motor starts. Check for high voltage spark output
from the ignition control. If there is no high voltage spark
output, check the reset button for the ignition control. If
there is still no high voltage output, replace the ignition
control.
Spark Cable
Check spark cable for loose terminations. Verify resistance
to be between 514
Ω
and 1068
Ω
. Replace if necessary.
Igniter / Sensor
Assembly (Located
inside Burner Assembly)
Check for visible damage to the igniter/sensor assembly. If
there is visible damage to the igniter/sensor assembly,
replace. Check the spark gap (.096” 2.44mm). If there is no
visible damage to the components, and no spark, replace
the igniter/sensor assembly. Also check for frayed or
damaged wires in burner tube. Replace components as
needed.
Ignition Control
Gas valve should open as the ignition control generates
the high voltage spark. Check for supply voltage to pilot
valve at terminal #5 and neutral. If no voltage is present,
check reset button for the ignition control. If there is still no
voltage to the pilot valve, replace ignition control.
Gas Control Valves
Check for supply voltage to pilot valve at terminal #5 to
neutral, if there is no voltage, trace wiring back to ignition
control. If there is supply voltage, connect a manometer to
the pressure tap fitting in the gas line. If there is voltage to
the pilot valve, but there is no gas pressure, replace gas
valve.
Flame will not stay on
Flame Sensor
To check flame sensor operation, connect a digital
multimeter (capable of measuring D.C. microamps)
between the flame sensor wire and flame sensor
connection on the ignition control. Flame sensor current is
to be 0.7 microamps, minimum. If these readings are not
achieved, replace igniter/sensor assembly. Also check for
any type of damage to flame sensor wire and connections.
NOTE: The D.C. microamp test must be conducted with
the oven in low flame (bypass) operation.
Power Supply
Set the temperature to the lowest temperature setting. If
there is sufficient microamp current, but the flame will not
stay lit, check for proper polarity of the power supply.
Ignition Control
If there is sufficient microamp current, and there is proper
polarity of the power supply, but the burner will not stay lit,
check the reset button for the ignition control. If the above
test is okay, replace the ignition control.
NOTE: Flame should be lit at this time.
