Frymaster GF14 - Manual (Page 14)

1-10
Pilot Does Not Remain Lit When Gas Valve Knob is Released
The electromechanical Honeywell gas valve used on the GF14 and GF40 fryers has a pair of
normally open coils (electromagnetic switches) that close when low voltage is applied to them. If
the coils do not close, the valve will not open to supply gas to the pilot or to the burner manifold.
Turning the gas valve knob to the pilot position and pressing it in bypasses the pilot coil, allowing
the pilot to be lighted. The pilot flame heats the thermopile, which generates the voltage required to
close the coils. If the pilot flame goes out when the knob is released, there are four probable causes:
1. Open or grounded high-limit: The high-limit thermostat functions as a normally closed
switch. If the high-limit is open or grounded, the gas valve coil will not pull in and no gas will be
supplied to the pilot or to the burner manifold.
Check and Corrective Action: Detach the high-limit leads from the gas valve and check for
continuity. If the high-limit fails the continuity check, it must be replaced.
2. Loose/corroded wiring connections on high-limit or thermopile: This has the same effect as
an open or grounded high-limit. If the gas valve coils do not receive the appropriate voltage
from the thermopile, they will not close and no gas will be supplied to the pilot or to the burner
manifold.
Check and Corrective Action: Check wiring connections for corrosion and tightness. Check
terminals to verify that they are securely attached to their leads.
3. Low or no voltage out of thermopile: If the tip of the thermopile is not surrounded by the pilot
flame, it will not generate sufficient voltage to the gas valve coils for them to close. No gas will
be supplied to the pilot or to the burner manifold.
Checks and Corrective Actions:
Observe pilot flame through the viewing port in the lower left corner of the frypot front baffle
assembly. If the pilot flame is less than 1-inch (25mm) adjust the pilot flame in accordance with
Section 1.7. If the flame is being blown away from the pilot, eliminate the draft that is causing it
to be blown away from the thermopile.
If the pilot flame correctly impinges the tip of the thermopile, connect a multimeter in series with
either of the thermopile leads and its gas valve terminal. Light the pilot and allow it to burn for
at least two minutes, then check the voltage output. If voltage is less than 400 millivolts, replace
the thermopile.
4. Malfunctioning gas valve: If either of the coils in the gas valve fails, no gas will be supplied to
the pilot or to the burner manifold.
Check and Corrective Action: If all the above checks are satisfactory, the gas valve has failed.
Replace the gas valve.