Hotbox Troubleshooting

This guide is to help troubleshoot PressurePro, Dragon, Landa, Largo & Other common hotboxes!


  1. Fuel Level: The first thing when troubleshooting hotboxes is to check the fuel level. The fuel pickup for all of these tanks is about 1" above the bottom. Ensure that the hotbox is full of fuel. 
  2. Fuel Filters: Ensure that the fuel filter looks clear. It will have a orange/yellow tint to it, but there should not be any debris. 
  3. Power/Fuse: Ensure that the unit has power going to the control panel. On Dragon hotboxes, they usually have a switch with an LED light in it. The switch light should come on when the button is flipped. Also ensure that the breaker is not tripped, and the fuse between the battery and power inlet is good. On dragon hotboxes, it is very common for the rocker switch with the LED light in it to go bad. 
  4. Flow/Pressure Switch: The most common failure on a hotbox is the Flow/Pressure switch. All PressurePro units use a Pressure Switch, while Dragon boxes use a Flow Switch. Pressure Switch Testing: Remove the 4 bolts that cover the switch. This will be a 3" long black plastic housing that is usually located either at the pump or on the inlet side of the hotbox. With the unit turned on and the cover removed, take a small screw driver and press the little button on the side of the micro switch. If nothing happens, the switch is bad. If the burner fires up, there is something clogging the inlet to the switch. Flow Sensor Testing: Flow Sensors are much easier to troubleshoot, you will need a strong magnet. Place the magnet on the body of the flow sensor until you feel a little click from inside. If the burner fires up, the flow sensor is bad and needs to be replaced.
  5. Not Pulling Fuel: If there is power to the hotbox and all the switches appear to operate normally, the Fuel Shutoff Solenoid on top of the blower motor may be bad. This is a little green unit on top of the fuel pump. It is not common for this to fail, but it does happen.