Cabinet Troubleshooting
3-2
Failure modes not accompanied by a master control display are shown below with possible causes
and tests.
Symptom Possible Causes Tests
Unit fails to power
up; fans don’t run.
• No power to cord.
• Blown 20 amp fuse.
• Circuit breaker open.
• Check for line voltage at the switch
and the transformer.
• Reset circuit breaker.
Unit powers up and
fans run; a display
fails to light.
• Broken or improperly
seated ribbon cable.
• Defective display.
• Switch ribbon cable from functioning
display to failed component to isolate
problem.
Unit powers up and
fans run; all
displays fail to light.
• Failed power supply.
• Check for 5VDC at communication
board and distribution boards.
Rows heat
improperly or not at
all.
• Improper wiring on
distribution board.
• Defective distribution
board.
• Defective heater.
• Defective sensor.
• Ensure heater leads and power inputs
on the distribution boards are properly
seated.
• Test for 208VAC input on distribution
board and 208VAC output from heater
leads to heater plate when the unit is
calling for heat.
• Switch power leads from properly
operating row to faulty row to isolate
problem.
• Check resistance of RTD lead against
temperature chart. See Page 2-4.
• Switch RTD lead from properly
operating row to faulty row to isolate
problem.
• Test continuity of heater plate.
