1-11
Pilot failures fall into one of two categories – failure to light or failure to remain lit.
Pilot Fails to Light
1.
Gas is not being supplied to the valve: Check for a closed gas cutoff valve upstream of the gas
valve. Also verify that the gas line quick disconnect fitting at the rear of the fryer (if so
equipped) is properly connected.
2.
Blocked pilot orifice: If gas is reaching the valve but the pilot will not light, check for an
obstruction in the pilot orifice, especially in new installations. If the orifice is clear, check to be
sure that the pilot adjustment screw is not completely closed.
Pilot Does Not Remain Lit When Gas Valve Knob is Released
The gas valve used on Dean millivolt 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 lit. 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. See page 1-10. 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 a
grounded or open 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 pilot flame does not surround the tip of the
thermopile, 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 located between the middle burners on the
frypot. If the pilot flame is less than 1-½ inches (38 mm) adjust the pilot flame in accordance
with Section 1.6. If the flame is being blown away from the thermopile, eliminate the draft that
is causing the problem.
If the pilot flame correctly surrounds the tip of the thermopile, see D on Page 1-9.
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:
See page 1-10 for check procedures to see if the gas valve has
failed. Instructions to replace the gas valve are found in section 1.7.3.
