Troubleshooting: If the Catalytic Heater Will Not Start

Gas Supply

1. If this is a new installation make certain that the fuel gas lines are aggressively and completely purged of air, liquid, and debris. Because of the small volume flowing through the heater, it can take a very long time to purge the lines with the heater gas train connected.
2. Verify gas pressure to the heater. Natural gas fueled heaters should receive 4 ½ inches of water column pressure. LPG fueled heaters should receive 11 inches of water column pressure. It is important that this pressure be verified with a gauge or manometer. Check the pressure with gas flowing through the heater, not dead-headed. If the heater is equipped with a shutoff valve the button should be pressed fully in when verifying pressure. The best place to check the pressure of the heater is as close to the heater input as possible. Never rely on pressure reading more than approximately one foot away from the heater input as there can be significant line pressure drop at these extremely low pressures.
3. Verify that the heater orifice is not obstructed. The orifice is located inside of the ¼ npt nipple on the back of the heater.
4. Read the heater label to verify that the proper fuel is being used (Natural Gas or LPG)

Electrical Supply

1. From the heater label, verify that you are using the proper starting voltage.
2. Verify that the voltage is as required. Check the voltage at the heater with power flowing through the heating element (under load).
3. Make sure that electrical power is applied per instructions in the manual and on the label. Once the heater is pre-heated and gas is sent into the heater, the electrical power should be continued per instructions so as to allow the heater enough time to be fully operating.

Other Issues

1. If you observe steam or vapor emitted from the heater or from a vent in an enclosure, this is an indication that the pad material inside the heater is wet (water or other substance). The heater will not function properly. If the liquid is something that will evaporate and leave no residue, the heater might eventually dry itself enough to be functional. If contaminated by a non-flammable substance that will not leave a residue in the heater pad material, it is possible to “bake” the heater in an oven at about 250 °F for several hours to evaporate the liquid.
2. If the face of the heater shows significant discoloration, this indicates that the heater may be contaminated, preventing the free flow of gas to the catalyst pad at the face of the heater.
3. There must be an adequate source of combustion air for the heater to function.