Heating (Ignition) Failure - Welbilt Frymaster FilterQuick easyTouch FQG120T Service Manual

1.16.1

Heating (Ignition) Failure

Heating (ignition) failure occurs when the ignition module fails to sense a pilot flame within the 90-second time delay
period and locks out. When this happens, the module sends 24 VAC through the SIB (smart interface board) alarm
circuit to the controller.
FQ4000 controllers display "HEATING FAILURE".
The three primary reasons for heating failure, listed in order of probability, are problems related to:
1. Float switch malfunction
2. Gas and/or electrical power supplies
3. Electronic circuits
4. Gas valve
PROBLEMS RELATED TO THE FLOAT SWITCH
The main indicators of this are that the fryer may light intermittently, fail to light or light
with low oil levels. A visual clue is the float switch (see Figure 33) is stuck in the down
position with oil over it or stuck in the up position with the oil level below it. Regular
cleaning of the float switch prevents this issue. Ensure when removing the float switch that
its position is clearly marked and replaced properly. Installing the float upside down will
change the switch from N/O to N/C. This could allow the empty frypot to ignite. See float
switch troubleshooting in Section 1.22.5.1.
PROBLEMS RELATED TO THE GAS AND/OR ELECTRICAL POWER SUPPLIES
The main indicators of this are that an entire battery of fryers fails to light and/or there are no indicator lights
illuminated on the fryer experiencing heating failure. Verify that the quick disconnect fitting is properly connected,
the fryer is plugged in with connector twisted and locked, the main gas supply valve is open, and the circuit breaker
for the fryer electrical supply is not tripped.
PROBLEMS RELATED TO THE ELECTRONIC CIRCUITS
If gas and electrical power are being supplied to the fryer, the next most likely cause of heating failure is a problem in
the 24 VAC circuit. Verify that the float switch is working properly. Installing it upside down will change the switch
from N/O to N/C. This could allow the empty frypot to ignite.
TROUBLESHOOTING THE 24 VAC CIRCUIT.
Some typical causes of heating failure in this category include a defective sensing wire in the ignitor assembly, a
defective module, a defective ignition wire, and a defective ignitor.
Occasionally, a heating failure situation occurs in which all components appear to be serviceable, but the unit
nevertheless goes into heating failure during operation. The probable cause in this case is an intermittent failure of
an ignition module. When the unit is opened up for troubleshooting, the module cools down enough to operate
correctly; however, when the unit is again closed up and placed back into service the module heats up and fails
PROBLEMS RELATED TO THE GAS VALVE
If the problem is not in the 24 VAC circuit or pilot system, it is most likely in the gas valve, itself. Before replacing the
gas valve, refer to Section 1.17.2 TROUBLESHOOTING THE GAS VALVE.
1-22
Figure 33
.