Frymaster manual PRO H50/55-SERIESGAS FRYERS, Service Procedures, 1.1Functional Description

PRO H50/55-SERIES GAS FRYERS

CHAPTER 1: SERVICE PROCEDURES

1.1Functional Description

Pro (H50/55) Series gas fryers contain a welded stainless steel frypot that is directly heated by a high efficiency infrared burner system requiring approximately 43% less energy than conventional burners to cook the same volume.

Self-contained combustion chambers (referred to as “burners”) are fitted into rails attached to the sides of the frypot, one on each side. Each combustion chamber is fitted with special ceramic tiles that are heated by burning a forced air/gas mixture. The tiles transfer heat to the frypot by means of infrared radiation, providing much more constant and uniform heat dispersion over the surface of the frypot than conventional burners. Because less heat is lost to the atmosphere in the process, compared to “open-burner” designs, less fuel is required to achieve and maintain temperature.

In full-vat units, gas flow to both of the burners is regulated by one electromechanical gas valve. In dual-vat units, each burner has its own valve. All fryers in this series are equipped with 24 VAC gas valve systems and electronic ignition.

1.1.1 Electronic Ignition System

An ignition module mounted in the component box (located behind the control panel) is connected to an ignitor assembly at the burner. The ignition module performs four important functions: it provides fuse protection for the 24-volt circuit, provides an ignition spark, supplies voltage to the gas valve, and proofs the burner flame. The module contains a 4-second time delay circuit and a coil that activates the gas valve. Three types are in use. A closed-box design is used in most fryers, but in some fryers built for export, the module resembles an interface board. A single dual-spark module is used on current production full-vat fryers. All dual-vat fryers use two single-spark modules.

The ignitor assembly consists of a spark plug, an enrichment tube, and a flame sensor.

Inside the Ignition Module

Out to

Gas Valve

To Alarm

25 V +

Coil

TD

HV

GND

Ignition Wire Flame Sensor

At start-up, the power switch is placed in the ON position, supplying approximately 12-volts DC to the heat-control circuitry in the controller or computer and to one side of the heat relay coils on the interface board. If resistance in the temperature probe indicates the temperature in the frypot is below 180ºF (82ºC), the current flows through a melt cycle circuit where a timer switch alternately closes for 6 seconds and opens for 24 seconds. If the temperature is 180ºF (82ºC) or above, the current flows through a heat circuit, bypassing the timer switch. In either case, ground is supplied to the other leg of the heat relay coils, which then close electronic switches in the 24 VAC circuit to provide current to the ignition module. Circuitry in the ignition module sends 24 VAC to the gas

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