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9. Troubleshooting
Condition
Unit is not operating or stops op-
erating
Fan is spinning but unit is not
putting out heat
High limit cutout trips or cycles
Relief valve has activated
Fuse or GFI blows
Large vibration or strange noise
coming from heater
Contactor is chattering (turning
on/off rapidly)
Note: Chromalox document PF506 provides additional information regarding troubleshooting.
© 2020 Chromalox,
Probable Cause
Motor has overheated
High limit cutout has tripped See condition "High limit cutout trips"
Heat exchanger has lost vac-
uum
Inlet or outlet are blocked
Heat exchanger is dirty
Failed heating element
Motor may not be spinning
at rated rpm
Heat exchanger has lost vac-
uum
Inlet or outlet are blocked
Heat exchanger is dirty
Unit has overheated
Short in wiring
Failed heating element
Fan-motor is unbalanced
Contactor is defective or
loose connections / short in
wiring
Corrective Action
Wait 10-15 minutes for motor to cool down
Check for signs of vacuum loss, such as leaks near
relief valve. If discovered, contact Chromalox and
arrange for service.
Clean unit using compressed air
Clean unit using compressed air
Contact Chromalox and arrange for service.
Check motor winding resistance
Check for signs of vacuum loss, such as leaks near
relief valve. If discovered, contact Chromalox and
arrange for service.
Clean unit using compressed air
Clean unit using compressed air
Contact Chromalox and arrange for service.
Check all wiring for loose or frayed connections
and tighten or replace
Contact Chromalox and arrange for service.
Check to see if set screw is loose. If loose, tighten
set screw and ensure fan blade is balanced.
Check for burn marks on the contactor terminals
and look for frayed or loose wires. Replace contac-
tor.
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