- 1). Check with a voltage meter that the furnace circuit breaker or fuse is working correctly. Check that any circuit breakers are switched on.
- 2). Have the propane pressure tested by your propane dealer, who will attach a special gauge to a test nipple on the furnace and assess whether the gas line is clear or blocked.
- 3). Test the coach battery with the voltage meter; it should read between 11 and 13.5 volts. Low voltage could mean a slower-than-ideal fan speed, which would lock out the ignition sequence.
- 4). Remove the glass inspection plate in the front of the furnace by releasing the two screws holding it in place. Inspect the combustion chamber, checking that the burner has not become clogged by rust flakes that have fallen from the exhaust flue. Measure the ignition electrode gap, and compare it with the specification given in your owner's manual. Run an ignition sequence to test that the electrode fires a strong, blue spark.
- 5). Check all the vents that comprise the system to ensure grease, dust or animal nests are not obstructing them. Inspect the furnace's vents -- one that pulls fresh air into the combustion chamber, one that expels exhaust gas, one that pulls cool air into the heat exchanger and one that expels heated air. If you detect reduced flow-through, the furnace may automatically shut down.
- 6). Familiarize yourself with the terminal layout of the furnace's time delay relay; each terminal will be marked with a printed sticker or an embossing on the relay's case. The voltage meter check should result in a constant 12-volt reading at the terminal fed from the circuit breaker or fuse, a reading that jumps from 0 volts to the resting voltage of the coach battery when the thermostat kicks on and an equal value at the third terminal approaching half a minute later.
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