An Inoperative 12 Volt Burner

1. With the Engine running and the Burner switch on, the Thermostat Dial turned up you should be able to hear the Blower motor running, feel air blowing out of the burner exhaust vent.

2. If your burner has a fuel pressure gauge this should be around 125 PSI and there is usually air bubbles visible in the burner filter clear bowl

3. The burner needs to have a certain amount of back pressure to activate usually around 800 PSI or above so you will need to use a pressure washer gun with Nozzle (preferred for testing) or a Jetter nozzle

4. With burner switch on, thermostat turned up and pressure gun pulled and you still have no burner: A) Verify you still have 125 PSI pressure if this is present but then quickly drops check the filter this may be plugged. B) You can verify the ignitor has spark by opening the top hinged ignitor door ( usually says Beckett 12 volt Power light) open the door , using an insulated screw driver jump the two springs leaving a ¼” gap and see if you have spark with the machine running.

5. If everything is good so far? The burner uses a Pressure switch in series with the thermostat switch to activate the fuel cut solenoid to turn the fuel on and off for the burner.

6. You can test these switches individually by jumping the connections on the switch, the pressure switch is a black rectangular box about 3” x 2 “Plumbed into the high pressure side of the water pump with a wire coming out of it, you can remove the 4 screws on the cover plate and jump the red and brown wires with the machine running and the burner switch on, thermostat turned up if the burner ignites replace the pressure switch if not we will test the thermostat.

7. To test the thermostat we will need to open the box that houses the thermostat, there are two wires that go to the thermostat we will need to jump those and then try the unit with a pressure gun and see if it burns if so replace the thermostat, if not the final test is the fuel cut solenoid.

8. The fuel cut solenoid is a green electrical coil located on the left hand side of the burner fuel pump it has a wire plugged into it usually running through a metal corrugated conduit, unplug the wire using either a DC volt meter or 12 volt test light verify you have power to the solenoid with the trigger pulled and then no power when trigger is released? If this is present and you still have no burner? Replace the fuel cut solenoid and solenoid block.

Steve Roylance has worked at HotJet USA for 25 years and has over 30 years experience in engineering, maintenance and customer service. For any service questions/concerns, give Steve a call toll-free at 1-800-624-8186 or email service@powerlineindustries.com.