35
Symptom
Possible Cause
Corrective Action
Thermostat closed, fan doesn’t
operate.
• Blown fuse.
• Faulty thermostat.
• Loose or disconnected wire.
• Faulty fan.
• Replace.
• Replace.
• Repair as required.
• Lubricate, repair or replace.
Thermostat closed. Fan
operates. Switch does not close.
• Loose or disconnected wire.
• Box lid or gasket not in place.
• Plugged pressure switch lines.
• Plugged or restricted exhaust vent.
• Baffle location incorrect.
• Faulty pressure switch.
• Repair as required.
• Put in place.
• Clean as necessary.
• Remove foreign matter.
• Re-position baffles at vent end.
• Replace only. Do not adjust.
Thermostat closed. Fan
operates. Pressure switch
closes. No glo-bar igniter.
• Faulty glo-bar igniter.
• Faulty circuit board.
• Replace.
• Replace.
Thermostat closed. Fan
operates. Pressure switch close.
Glo-bar energizes. Valve does
not open.
• Disconnect gas valve wires.
• Faulty circuit board.
• Faulty gas valve.
• Repair as required.
• Replace.
• Replace.
Thermostat closed. Fan and
glo-bar /spark igniter operate.
Ignition occurs, burner cycles
off in less than 60 seconds.
• Low gas pressure.
• Baffle improperly positioned.
• Faulty pressure switch.
• Restricted flue vent.
• No electrical ground.
• Reversed polarity.
• Provide required gas pressure.
• Re-position baffle at vent end.
• Replace.
• Remove foreign matter.
• Connect electrical ground to junction box.
• Repair.
Thermostat closed. Fan and glo-
bar /spark igniter operate. After
45 seconds glo-bar shuts off
(15 seconds for spark igniter).
No ignition.
• Closed gas supply.
• Dirty or restricted orifice.
• Faulty valve. Disconnected wire.
• Inlet pressure exceeds 14 inches
W.C.
• Open all gas connections.
• Remove. Clean with a soft object.
• Replace or repair.
• Lower inlet pressure.
Loss of heater efficiency.
• Low gas pressure.
• Dirty or restricted orifice.
• Foreign matter inside burner.
• Unit cycles on and off.
• Reflector is dirty.
• Reflector not in place.
• Clogged fan blower.
• Provide required gas pressure.
• Remove. Clean with a soft object.
• Clean as necessary.
• Check previous symptom.
• Clean with aluminum cleaner and soft
cloth.
• Put in place.
• Clean.
Radiant tube leaking burnt
gases.
• Loose tube connections.
• Holes or cracks in radiant tubes.
• Ensure that tubes are fully connected
and clamped properly.
• Replace.
Condensation.
• Stack length is too long.
• Light gauge vent stack used.
• Contaminated combustion air.
• Shorten stack length.
• Minimum of 26 ga. vent pipe required.
• Provide fresh air inlet duct.
Tube bowing.
• Insufficient combustion air.
• Over fired.
• Contaminated combustion air.
• Heater unable to expand properly.
• Provide 1 sq. in. of free air for every
5,000 BTU/h of input.
• Check gas pressure and orifice size.
• Provide fresh air inlet duct.
• Remount with flexible inlet or vent pipe.
Tube corroding.
• Contaminated combustion air.
• Provide fresh air inlet duct.
Visual inspection of burner
operation not possible.
• Dirty or sooted sight glass.
• Unit mounted upside-down.
• Remove, clean or replace.
• Mount correctly.
Stack sooting.
• Insufficient combustion air.
• Improper gas.
• Dirty fan or blockage.
• Provide 1 sq. in. of free air for every
5,000 BTU/h of input.
• Correct with proper gas input (or clean).
Odor or fumes in space
(normal during first firing and
will subside after initial burn off,
approximately 20 minutes).
• Vaporized solvents decomposing
when contacting radiant tubes.
• Evaporation of oils, solvents at floor
level.
• Loose tube / vent connections.
• Provide proper ventilation.
• Provide proper ventilation.
• Tighten tube clamps to 40-60 ft-lb.
• Seal vent pipes.
Chart 5.1
Troubleshooting Guide
