Troubleshooting a Noisy RV Furnace

Travel trailer parked in the snow

If you have ever been awakened by a noisy RV furnace you are probably eager to discover that there could be a number of reasons for the clatter. When the fan kicks on in the furnace, it can make quite a racket. You might even be hearing the pilot light coming on. There are some things you may check to troubleshoot a noisy RV furnace.

Step 1 - Inspect the Furnace

Inspect the RV furnace to see if you can find something obvious. Check the air register and make sure that it is clean and free of debris. See if the fan could be making the noise. When the furnace comes on and you find out it is the fan rattling, ensure there are no loose parts. If all is fine, you could install some soundproofing in the air register to help quiet it down.

Step 2 - The Pilot Light

Blue flame of a pilot light

If your RV furnace is gas, it could be the pilot light coming on. The gas pushing through the pipes and igniting the pilot can cause a fair amount of noise. The noise should calm down once the pilot is lit. However, if it doesn’t you may have to take a look at the gas lines too and determine if there is a problem there.

Step 3 - An Obstructed Exhaust

If you still haven't found the source of the noise, check the exhaust venting. It needs to be clear of all debris for the furnace to work properly. It's possibly that debris of some kind has worked its way into the vent. A leaf or a piece of paper can cause an annoying rattle.

Step 4 - Time Delay Relay Switch

An RV furnace has a time delay relay switch that performs two jobs. The first job is to handle the high current needed to run the blower motor. The second is to let the blower continue to run for up to 90 seconds after the thermostat has reached the set temperature. The relay should be open and have power from the circuit breaker.

Step 5 - Blower Motor

man repairing a furnace

It is possible that the blower motor may not be working properly. The blower motor drives two fans that provide separate air flow for the combustion to take place. It also runs the heat exchanger that is used to separate the heat from the gas while preventing fumes from escaping into the living space.

Step 6 - Sail Switch

The sail switch is an "On" and "Off" switch that normally stays "Off". Air from the blower hits the sail switch with enough force to close it and allows the electrical current to continue on. Some of the causes of this going bad could be a low battery, restricted air flow (return), or a faulty switch. It could be caused by inadequate outlet vents and restricted combustion air inlet.

These are just a few things that can be looked at to see why you have a noisy RV furnace. By checking on each thing individually you should be able to locate the problem. You can then make the necessary repairs to quiet down that noisy furnace. There could be more wrong with the furnace than meets the eye, however. If you have gone through all possible avenues, you may want to have a professional look at the furnace. You should be able to get the noise out of your RV furnace for good.