Replacing the High Limit

This is a safety, manual reset control, which senses the temperature of the oil. If the oil temperature exceeds 425°F (218°C), this switch opens and shuts off the heat to the vat. When the temperature of the oil drops to a safe operation limit, manually reset the control by pressing the reset button.

Reset switches are located in the front edge of an electrical panel on the right side of the unit beside the JIB. Open the right door, depress the raised part of the rocker switch for the affected well, and release switch. If high limit resets, the oil starts heating. If high limit does not reset, perform following checkout procedure.

Checkout

To avoid electrical shock or property damage, move the power switch to OFF and disconnect power.

1. Open right door and remove the JIB.

2. Remove one screw and panel cover.

3. Locate thermocouple wires from element and disconnect from high limit.

4. Using a multimeter and the chart below, check the multivolt reading between the thermocouple wires and compare with the chart of the J-Type thermocouple. If the reading matches the chart, the thermocouple on the element is good and continue onto the next step of checkout. If not, replace the thermocouple.

   NOTE: Oil temp must be 380°F (193°C) to perform this check.

5. Connect a known good high limit control into wiring for the suspect thermocouple and control.

6. Connect electrical power and operate vat. If vat does not overheat, replace defective control with known good part.

7. If vat overheats, perform more checkouts of other components (relays, contactors, probes, etc.) and replace the heating element as the last resort.

Replacing

1. Tag and remove lead wires to module.

2. Using 3/8 inch wrench or socket, remove two acorn nuts securing control to unit.

3. Install a new control in reverse order.

For additional troubleshooting refer to the JWF Light Code Chart.