Thermostats; Accessing Fryers For Servicing - Frymaster Pro H50-Series Service And Parts Manual

12VAC Power to Controller
24VAC Power to Right M odule
120 VAC Power
120 VAC Power to Blowers
24VAC Power to Full- or Right-vat High-Lim it
24VAC Power to Left High-Limit (if present)
Probe Resistance (Full- or Right-vat) *
Probe Resistance (Left - if present) *
Probe Isolation
High-Limit Continuity (Full- or Right-vat)
High-Limit Continuity (Left - if present)
** Disconnect 15-pin harness from controller before testing probe circuit.
** See Probe Resistance Chart at end of chapter.
*** 5 mega-Ohms or greater.

1.1.3 THERMOSTATS

Pro Series (H50) gas fryers have temperature probes located on the front centerline of each frypot
(dual-vat frypots have two probes, one in each vat). In this type of thermostat, the probe resistance
varies directly with the temperature. That is, as the temperature rises, so does resistance, at a rate of
approximately 2 ohms for every 1º F. Circuitry in the controller monitors the probe resistance and
controls burner firing when the resistance exceeds or falls below programmed temperatures
(setpoints). The temperatures are programmed by means of a keypad on the face of the controller.
Pro Series (H50) fryers are also equipped with a high-limit thermostat. In the event that the fryer
fails to properly control the oil temperature, the high-limit thermostat prevents the fryer from
overheating to flash point. The high-limit thermostat acts as a normally closed power switch that
opens when exposed to temperatures above 425ºF to 450ºF (218ºC to 232ºC). The different types of
thermostats have different part numbers for CE and non-CE models and are not interchangeable.
1.2

Accessing Fryers for Servicing

Moving a fryer filled with cooking oil may cause spilling or splattering of the hot
liquid. Follow the draining instructions in Chapter 4 of the Installation and Operation
manual (P/N 819-5991) before relocating a fryer for servicing.
1. Shut off the gas supply to the unit. Unplug the power cords. Disconnect the unit from the gas
supply.
2. Remove any attached restraining devices and relocate the fryer for service accessibility.
FREQUENTLY USED TEST POINTS FOR INTERFACE BOARD 106-0386
Test
50VAC Scale
50VAC Scale
250VAC Scale 11 on J3 and GROUND
250VAC Scale 12 on J3 and GROUND
50VAC Scale
50VAC Scale
R x 1000 OHM S 2 and 6 on J3 or 13 and 14 on J2
R x 1000 OHM S 2 and 6 on J1 or 14 and 15 on J2
R x 1000 OHM S 6 on J1 or J3 and GROUND
R x 1 OHM
R x 1 OHM
Meter
Setting Pins
1 and 3 on J3 or J2
8 on J3 and GROUND
9 on J3 and GROUND
9 on J1 and GROUND
9 on J3 and Wire 13C on Gas Valve
9 on J1 and Wire 12C on Gas Valve
DANGER
1-4
Results
12-18
22-28
110-125
110-125
22-28
22-28
**
**
***
0
0