Sequence Of Operation - Vulcan-Hart 1GR45A Service Manual

SEQUENCE OF OPERATION

Refer to schematic diagram AI 2727 for Cooking Control operation.
NOTE: Make sure melt select switch reflects type of shortening being used (solid/liquid).
1. Conditions.
A. Fryer connected to correct supply voltage and properly grounded.
B. Gas supply is on and gas combination valve is open.
C. Power switch to the fryer section in the off position.
D. Shortening at proper level in fry tank and below last set point temperature used.
E. Manual drain valve closed (drain valve interlock switch N.O. is closed).
F. High limit thermostat closed.
2. Turn power switch on.
A. 24VAC transformer energized.
3. Ignition module is powered (24VAC), initializes and generates spark at ignitor.
A. Pilot voltage (PV) N.O. contacts close, pilot valve coil energized and valve opens for gas flow to pilot.
1) Pilot flame established. A micro amp flame sense current is rectified to ignition module through
ignitor cable and sparking stops.
2) Main voltage (MV) N.O. contacts close and provides ignition status input signal (24VAC) to cooking
control.
B. If pilot is not established within 90 seconds of the ignition module being energized, the ignition module
locks out power to gas valve.
1) The system remains locked out until the power switch is cycled to reset the system and re-start the
ignition trial cycle. (wait 5 minutes for gas to dissipate)
4. Cooking control evaluates input signals from: Ignition status; Drain valve interlock; and temperature probe.
A. Main valve coil energized and valve opens for gas flow to burners.
1) Burners light and heat the shortening in fry tank.
NOTE: As long as the ignition control module senses a pilot flame, the internal main voltage (MV)
contacts (N.O.) on the ignition module remain closed, and main gas valve stays on.
5. Shortening reaches set temperature.
A. Cooking control de-activates the heat output (24VAC).
1) Main valve coil de-energized and valve closes.
2) Gas flow stops and burners go out.
6. Cooking control cycles heat output on shortening temperature until: power switch is turned off; ignition input
status is removed; drain valve interlock input status is removed; temperature probe input is outside
acceptable limits or a high limit condition occurs.
7. If shortening reaches 450EF or higher: high limit thermostat opens, power is removed from the pilot valve coil
and valve closes to stop pilot gas flow.
A. Ignition trial cycle will start but pilot will be unable to light.
B. Fryer operation can resume when the temperature drops below 415°F.
F25377 (March 2010)
GRA SERIES GAS FRYERS - ELECTRICAL OPERATION
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