Troubleshooting Guide

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Control Power OFF

Main power not on. Check power supply.
Defective control transformer. Replace transformer.
Main line fuse blown. Replace fuse.
Control fuse blown. Replace fuse.
Short in system. Find short and repair.
Bulb burned out. Replace bulb.

Blower switch ON, blower not running.

Motor starter overload relay tripped. Reset overload relay. Check motor load. If overloaded, turn off. Check blower for reason.
Belt broken. Replace belt.
Control relay defective. Replace relay.
Motor defective. Replace motor.
Loose connection. Tighten wires.

Circulation air flow lost.

Defective wiring (open circuit). Find and correct defective wire.
Dirt in air flow switch tubing. Clear tubing.
Defective air flow switch. Replace air flow switch.

Excessive noise and vibration.

Blower bearings need lubrication. Lubricate bearings. Replace bearings if needed.
Foreign object in fan wheel or housing. Remove foreign object.
Fan out of balance. Check for physical damage. Re-balance or replace fan wheel.

Conveyor not running.

Broken drive chain. Replace chain.
Torque limiter not adjusted. Adjust torque limiter.
Heat sensor sensing hot part. Slow conveyor belt so parts stay longer in cooldown.

Oven not purging.

Bulb burned out. Replace bulb.
Wire on pilot light loose. Check and tighten wire connection.
Defective purge timer. Replace purge timer.

Pilot will not light.

Flame safety relay tripped. Reset flame relay.
Spark plug gap too wide. Readjust spark plug for .03 approximately. Clean and re-install.
Pilot gas flow too weak. Adjust pilot gas flow.

Burner will not light.

Low gas pressure switch set too high. Adjust switch in accordance with gas piping.
Pilot gas setting too lean to monitor pilot. Adjust pilot shut off cock needle valve for more gas. (1/4 turn at a time)

Main burner on. Oven will not come up to temperature.

Main burner gas cock in closed position. Open main burner gas cock slowly.
Control valve not operating properly Check for proper solenoid action. Check lead wires for continuity. Repair as needed.
Motorized shut off valve auxiliary switch not energized. Check the manufacturer's instructions and adjust switch for proper operation.
Defective thermocouple or loose thermocouple wire Check wire connections and tighten. Check for broken wire, replace. Check for defective thermocouple, replace.
Temperature control instrument out of adjustment or is defective. Check instrument in accordance with manufacturer's manual. Replace if necessary.

Heat switch ON: oven not heating.

Heater circuit fuse blown. Check and clear shorts. Replace fuse.
Defective thermocouple. Replace thermocouple.
Defective temperature controller. Refer to controller manual.

Oven slow to reach temperature.

Heater circuit fuse blown. Check for, and clear shorts. Replace fuses.
Loose wires on heater elements. Inspect and tighten wires.
One or more defective heating elements. Inspect heater plug and replace defective elements.

Poor temperature uniformity

Poor loading practice. Place load evenly in oven with proper clearance for air circulation.
Door not properly sealed. Inspect, lubricate and adjust latching mechanism. Inspect door seals. Adjust or replace.
Exhaust damper not adjusted correctly Adjust damper to correct setting. If unsure of setting consult manufacturer.

Alarm horn sounding.

Oven exceeding maximum temperature rating. Temperature controller set too high. Re-adjust excess temperature controller set point. Press reset button on front of excess temperature controller.
Red "Excess Temperature" light is ON. Defective thermocouple. Replace.
Faulty instrument adjustment. Refer to manufacturer's instruction manual.