Lincoln 3270-2 Convection Oven User Manual


 
Impinger X2 – Digital Service Manual – Dom & Int’l
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thermocouple. The thermocouple should read approx.
11Ω. If these readings are not achieved, replace the
thermocouple. If these readings are correct, proceed.
Oven control If the thermocouple checks good, but the oven control
display indicates that there is a thermocouple failure,
replace the oven control. If the oven control indicates a
temperature reading, but the oven will not heat,
proceed.
Main gas valve Check to see that the switch on the valve is in the “ON”
position. Check for supply voltage to main valve. If
there is voltage present, check to see that valve is
opening. Connect manometer to pressure tap on outlet
side of valve. If there is voltage to the valve, but no
output gas pressure, replace the valve.
Temperature regulation valve Check for supply voltage at temperature regulation
valve. If no voltage is present, trace wiring back to
electronic temperature control. If voltage is present,
listen for valve to open and close. Also check for opens
or shorts in the operating coil. Replace temperature
regulation valve as needed.
Oven control Check for 3 – 24VDC from the oven control at terminals
#J2-6 and J2-9. If there is no output voltage, replace
oven control. If there is output voltage,
Proceed.
Modulating valve Check for 3-24VDC at the modulating valve. If no
voltage is present, trace wiring back to the oven
control. If voltage is present, listen for valve to open
and close. Also check for opens or shorts in the
operating coil. Replace modulating valve as needed.
Intermittent heating Thermal/Overload of main fan
and burner blower motors
The main fan motor and burner blower motor are
equipped with internal thermal protection and will cease
to operate if overheating occurs. As the motors over-
heat and then cool, this will cause the units to cycle on
and off intermittently. Improper ventilation or lack of
preventive maintenance may cause this. Also, most of
the problems listed under “Oven will not heat” can
cause intermittent failure.
Conveyor will not run NOTE: The ovens may contain two, three or four conveyor drive systems using like
components. The trouble shooting sequence will be the same for each of the conveyor
drive systems
Power supply Check circuit breakers, reset if required. Check power
plug to be sure it is firmly in receptacle. Measure
incoming power, call power co. if needed.
Switch, oven power Check continuity between switch terminals. Replace
switch as needed.
Relay, main fan Check for supply voltage to relay terminal #13. If
voltage is not present, trace wiring back to power
supply. If voltage is present, check for supply voltage at
terminal #14. If there is no voltage at terminal #14, and
the relay is energized, replace the main fan relay.
Transformer, control Check for supply voltage to primary of transformer. If
no voltage is present, trace wiring back to the main fan
switch. If voltage is present, check for 24VAC at
transformer secondary.
If there is primary voltage but no secondary voltage,
replace burner/control transformer.
Switch, conveyor reversing Check for continuity between switch terminals. Replace
switch as needed.
Conveyor motor Check for supply voltage to the motor. If no voltage is