Frymaster FBRA18 Series manual Temperature Probe

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The relays in earlier design boards are soldered on and cannot be replaced. Later design boards fea- ture replaceable plug-in relays. In earlier designs boards, a heat relay (K2) switches 24VAC to the ignition and gas valve circuits when the controller heat logic circuit calls for heat. Simultaneously, a blower motor relay (K4) switches 120VAC to the blower motor. In later design boards, relay K3 serves as both the heat relay and blower motor relay.

FBRA18 rethermalizers use interface board 806-9592, often referred to as a water board.

1J2

1

K1

 

K2

HEAT

 

WATER

 

 

 

K3

BLOWER

J3

POWER

J1

CYCLE WATER BLOWER

INTERFACE BOARD P/N 806-9592

On interface board 806-9592, the heat (or cycle) relay (K1) switches 24VAC to the ignition and gas valve circuits when the controller’s heat logic circuit calls for heat and the lower water level sensor is grounded (i.e., the water level in the cookpot is above the lower water level sensor). If the water level in the cookpot is below the upper water level sensor, the water relay (K2) closes, switching power to the normally closed water solenoid valve, causing it to open. When the water level reaches the upper sensor, the relay opens, cutting power to the valve, causing it to close. The blower relay (K3) closes and switches 120VAC to the blower motor only when the heat relay (K1) is closed. The board has four LEDs to assist in troubleshooting. Three of the LEDs (CYCLE, WATER, and BLOWER) are arrayed along the lower edge of the board. The fourth LED (POWER) is located at the right edge of the board. When the cycle, water, and blower LEDs are illuminated, they indicate that the associated relay is closed. The power LED indicates that 24VAC is being supplied to the interface board by the transformer.

TEMPERATURE PROBE

A temperature probe is located on the front centerline of the cookpot. The probe is a type of thermo- stat in which the resistance varies directly with the temperature. That is, as the temperature changes, so does resistance, at a rate of approximately 2 ohms for every 1° of rise or fall. Circuitry in the controller monitors the probe resistance and controls burner firing when the resistance exceeds or falls below a programmed temperature (setpoint). The temperature is programmed by means of up or down arrow buttons on the face of the controller.

WATER LEVEL SENSORS (FBRA18 Only)

A pair of water level sensors is arranged one above the other on the left front of the FBRA18 cook- pot. When water contacts the sensors they are grounded. The lower sensor acts as a safety device to keep the burner from firing when there is no water in the cookpot. When the sensor is grounded by contact with water, a transistor on the interface board is biased and the heat relay (K1) pulls in, sup- plying power to the blower via relay K3 and to the gas valve via the ignition modules. Grounding

6-3

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Contents Hour Service Hotline Canada Page FBR18 & FBRA18 Series GAS Rethermalizers Table of Contents Parts List Parts Ordering and Service Information Safety InformationInstallation, Operating, and Service Personnel Equipment DescriptionDefinitions Shipping Damage Claim Procedure What to do if your equipment arrives damagedGeneral Installation Requirements Caster/Leg Installation Incoming Gas Pressures Connecting to the Gas Supply Converting to Another Gas Type Introduction FBR18/FBRA18 Digital ControllerOperating the FBR18/FBRA18 Timers Boiling-Out the Cookpot Shutting the Rethermalizer Down Daily Checks and Services Quarterly Checks and ServicesSemi-Annual Checks and Services Clean Combustion Air BlowerCheck Burner Manifold Pressure Burner Manifold Gas Pressures Introduction Troubleshooting Guides To FBRA18 units onlyProblem Yes Has the correct setpoint Yes Replacing the Controller or Controller Wiring Harness FBR18 & FBRA18 Series GAS Rethermalizers Service Procedures Functional DescriptionController and Mechanical Timers Temperature Probe Cleaning the Gas Valve Vent Tube Checking the Burner Manifold Gas PressureMeasuring Flame Current Replacing the Temperature Probe Replacing the Interface BoardReplacing an Ignitor Assembly Replacing an Ignition ModuleReplacing a Burner Assembly Replacing the Combustion Air BlowerReplacing the Gas Valve Troubleshooting and Problem Isolation Replacing the CookpotIgnition Failures Incoming Gas Pressures Improper Burner FunctioningPage Improper Temperature Control Troubleshooting the Gas Valve Troubleshooting the 24 VAC Circuit in FBR18 Units Unit is Connected to24 VAC Circuit in FBR18 Units Troubleshooting the 24 VAC Circuit in FBRA18 Units Is PowerIs 24VAC Present on COM No terminal of latch Relay? Harness Is J1 pin 24VAC Circuit in FBRA18 Units Troubleshooting the Temperature Probe Probe Resistance Chart Wiring Diagram for FBR18 Units 8050417DFBRA18 Units FBR18 & FBRA18 Series GAS Rethermalizers Parts List Burner System ComponentsCabinetry and Associated Components Control Box Assembly and Associated Parts, FBR18/ FBRA18 Controller and Component Box Assemblies Cooking Timer Control Panel Components Cookpot, FBR18 Cookpot, FBRA18 Gas Supply Components Plumbing Components Page Service Hotline
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