Frymaster BIH52 - Manual (Page 18)

3-1
Inside the Ignition Module
TD
Out to
Gas Valve
To Alarm
25 V +
GND
HV
Ignition Wire Flame Sensor
Coil
CHAPTER 3: SERVICE PROCEDURES,
TROUBLESHOOTING AND WIRING DIAGRAMS
3.1 Functional Description
H52 Series 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 the burning of a forced air/gas mixture. The tiles transfer their heat to the frypot
by means of infrared radiation, providing much more constant and uniform heat dispersion over the
surface of the frypot than do conventional burners. Because relatively less heat is lost to the atmos-
phere in the process, compared to “open-burner” designs, less fuel is required to achieve and main-
tain a given frypot 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 24VAC gas
valve systems, and all are configured with electronic ignition.
THE ELECTRONIC IGNITION SYSTEM
An ignition module mounted in the component box or
“shield” (located behind the control panel) is connected to
an ignitor assembly at the burner. The ignition module
performs three important functions: it 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 designs
are in use. The module used in Australian export units
resembles an interface board. A closed-box design is used
in units built for the U.S. and other export markets. Before
mid-2001, fryers (other than Australian) were equipped
with two 807-1006 modules. Fryers built after late 2000 to
mid-2001 are equipped with two 807-3365 (dual vat) or one
807-3366 (full vat) module. Fryers built between late-2000
and mid-2001 may have either configuration. Australian
units continue to use two 807-2971 modules.
The ignitor assembly consists of a spark plug, an enrichment tube, and a 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 24VAC circuit to