Frymaster H50 manual Interface Board

valve via a normally closed high-limit switch (and, in fryers with built-in filtration systems, a normally closed drain safety switch). Simultaneously, the module causes the ignitor to spark for 4 seconds to light the burner. A flame sensor verifies the burner ignition by measuring the flow of microamps through the flame. If the burner does not light (or is extinguished), current to the ignition module is cut, the gas valve closes, and the ignition module “locks out” until the power switch is turned off and then back on. A probe monitors the temperature in the frypot. When the programmed setpoint temperature is reached, resistance in the probe causes the heat cycle circuitry in the controller to cut off current flow through the heat relay. This in turn cuts off the 24 VAC to the ignition module, causing the gas valve to close.

1.1.2 Interface Board

The information contained in this section applies to Pro (H50/55) Series gas fryers ONLY.

All fryers in this series have an interface board located in the component box behind the control panel. The interface board provides a link between the controller/computer and the fryer’s individual components without requiring excessive wiring, and allows the controller to execute commands from one central point. This standard interface board is also used in a number of fryer types besides the Pro Series.

K2 and K3 are double-pole-double-throw (dpdt) relays that supply 24VAC to the ignition and gas valve circuits, as well as 120VAC to the blower motor. The relays on this board plug into sockets, and if either fails, it can be replaced individually.

LEDs (labeled D1 through D7) are arrayed around the board to assist in troubleshooting.

		SOUND			J2								GND
		1							13
					1	4	7	10
		2									F2	Ignition		D7
GND					2	5	8	11	14	D6	2 AMP Module
		3			3	6	9	12	15					AIR
										12V
	3	6	9	12						3	6	9	12
J1	2	5	8	11						2	5	8	11	J3
	1	4	7	10						1	4	7	10

INTERFACE BOARD

LED DIAGNOSTIC LIGHTS

D1 24 VAC to left gas valve (dual vat only)

GND V2D

PWR

AD

AS

V2S

D1

GV

	HEAT
	RELAY
D2	PWR AND
	BLOWER
	MOTOR
GND	RELAY
	K2

K1

K4

D3

24V

HEAT

RELAY

AND

BLOWER

MOTOR RELAY

K3

	D5
Blower	GV
Motor	GND
2 Amp

	V1D
	PWR
	ALR
D4	V1S
	PWR
	GND

D2	24	VAC to left ignition module
D3	24	VAC from transformer
D4	24	VAC to right ignition module
D5	24	VAC to gas valve (right valve if dual vat)
D6	12	VAC from transformer
D7	CE and Japanese units only: air switch closed

INTERFACE BOARD P/N 106-0386

NOTE: Although the printing on some boards may indicate 2 Amp fuses, 3 Amp fuses (P/N 807-3843) must be used. In full-vat fryers, the relay for the left side (K2) may not be present.

The chart on the following page illustrates current flow through the board, and the table at the top of page 1-4 identifies frequently used test points.

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