PROBABLE CAUSE
(The most recurring probable cause is listed first)
REMEDY
(Repairs should only be made by a qualified technician)
Heating / Burner System – Natural Gas or Liquid Propane Fired
Pilot will not light. Burner will not fire.
Trigger not pulled.
Thermostat not turned up.
Poor ground.
Gas valve turned off.
No voltage to valve.
Pilot orifice plugged.
Defective ignition module.
Defective pressure switch.
Defective transformer.
Defective flow switch.
Defective thermostat.
Faulty rocker switch.
Igniter not working.
Turn switch on. Press the reset switch.
Pull trigger. Burner should fire only when the trigger is pulled.
Adjust thermostat up.
Check & clean ground connections.
Turn gas valve on.
Check for 24 VAC between pilot valve (PV) & PV/MV. Valve will operate
between 20.5 & 28.5 VAC.
Remove orifice & clean.
Check for 24 VAC incoming @ 24v & 24v ground. (If you detect voltage
to module, but not through module, replace).
Check for 24v output. If no voltage, replace.
Replace.
Replace.
Replace.
Replace.
Test for spark. Test for continuity between ignition wire & ground.
WARNING! High voltage igniter can cause electrical shock.
Pilot lights, but burner will not fire.
Check for 24 VAC between main valve (MV) & PV/MV
when trigger pulled & unit on.
Failure to complete circuit to main valve.
Damaged or loose pilot assembly.
Insufficient or excessive gas pressure.
Check for continuity between ignition module ground &
If no VAC at the valve, replace module. If you get voltage, replace valve.
Check for controls continuity to main valve (thermostat, pressure switch,
flow switch).
Check for loose ignition wires.
Refer to installation guidelines. (Consult with a qualified gas technician)
Assure good ground.
Burner fires, but goes out.
Excess draft.
Protect from windy conditions. Install draft diverter.
Turn gas off. Call gas supplier.
NG or LP odor is present.
WARNING! Check all NG connections
with soap solution before operation.
Valve stuck.
Turn main gas valve off. Replace valve.
Discharge water temperature too high.
Incoming gas pressure to high.
Clean or replace spray nozzle, de-scale coil, & remove obstructions.
Lower gas pressure.
Replace spray nozzle with proper size.
Discharge water temperature not
reaching max. operating temperature.
Draft under burner manifold.
Increase gas pressure or install additional jets.
Prevent down draft with installation of down draft diverter. Prevent side
draft with nonflammable barrier.
Burner continues to fire even when
water is not being sprayed.
Faulty burner control circuit.
Main gas valve is stuck open.
Turn machine off immediately. Replace flow, vacuum, pressure, or
temperature switches.
Turn gas off. Replace main gas valve.
Valve/ Ignition module has been
subjected to moisture, had water
sprayed on it, or has been submerged
in water & does not work.
Flood or accidental spraying.
Replace valve / module: Do not attempt to repair or clean.
Heating / Burner System – Diesel Fired
(Additional Diesel Fired burner troubleshooting flow chart on next few pages)
Soot on coil exterior
Exhaust restricted
Air intake restriction
Improper voltage at burner motor
Adjust air band and fuel pressure to compensate
Increase air or decrease fuel. Coil may need cleaning
Remove restriction if obvious. Check for sooted coil
Remove restriction if obvious. Adjust air bands. Check fan
Check generator output if equipped. Check battery or charging system.
Improper or restricted fuel nozzle
Fuel gun assembly out of adjustment
Replace fuel nozzle
Adjust gun assembly location
Burner “Puffs” black smoke
Too much fuel pressure
Not enough air flow
Adjust fuel pressure at fuel pump
Adjust air bands
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