Chapter 7: Service Procedures; Functional Description; Pilot System Configuration; Electronic Ignition Configuration - Frymaster 47 SERIES Installation, Operation, Service, And Parts Manual

CHAPTER 7: SERVICE PROCEDURES

7.1

Functional Description

The 47 Series fryers contain a welded stainless
steel frypot that is directly heated by gas
flames that are diffused evenly over its lower
surface by ceramic "targets."
In full vat configurations, the flames originate
from orifices in a U-shaped burner manifold
positioned beneath the frypot. In dual (split)
vat configurations, the U-shaped manifold is
replaced by a pair of J-shaped manifolds, one
for each vat. The diameter of the orifices dif-
fers for natural and LP gas as indicated in the
accompanying table.
47 Series Orifice Sizes
Gas Drill Size
Natural
LP
Gas flow to the manifold(s) is regulated by an
electromechanical gas valve. This series of
fryers is equipped with a 24-volt valve system.
Units with thermostat controls will have a pi-
lot ignition (millivolt) system, and those with
other type controllers may be configured with
either a pilot ignition (millivolt) system or an
electronic ignition system.

PILOT SYSTEM CONFIGURATION

The pilot system is comprised of the pilot ori-
fice, pilot hood, and a thermopile. The pilot
serves two purposes. The first is to light the
burner, the second is to heat the thermopile.
In operation, the thermopile is in contact with
the pilot flame and generates millivolts. The
millivolt output passes through a normally
closed high-limit switch and energizes the gas
valve pilot coil, which in turn opens the pilot
valve. If the pilot flame is extinguished, volt-
age is lost to the gas valve pilot coil and the
pilot valve closes. A separate 24-volt circuit,
47 SERIES GAS FRYERS
Millimeters
53 1.45
65 0.86
activated by the fryer ON/OFF switch, pro-
vides voltage through the thermostat or con-
troller to the gas valve main coil, which opens
the main valve. The gas valve is constructed
so that the main valve will not open if the pilot
valve is not open. The pilot flame must be
manually lit when the fryer is first placed into
operation.
ON/OFF
Controlling Thermostat
or
Controller
Thermopile
Pilot

ELECTRONIC IGNITION CONFIGURATION

In units configured for electronic ignition, an
ignition module connected to an igniter as-
sembly replaces the pilot system. 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 pilot flame.
Inside the Ignition Module
Out to
Gas Valve
To Alarm
25 V +
25 V GND
7-1
Switch
Line Voltage
Line Voltage
24 VAC
Main Coil
Transformer
Gas Valve
High-Limit
Thermostat
Pilot Coil
The Pilot System
Coil
TD
HV
Ignition Wire Flame Sensor