I have a 2003 Forest River Sunseeker Class C motorhome. I bought this recently and don’t know much about all these things, so I read your column diligently. Recently it was 23° outside and I had trouble getting the furnace to start. Once it started it was incredibly noisy. Is something wrong, or is this just the way the furnace is on an old RV? Thank you. —Shanti
To provide more specific troubleshooting information I need to know the make and model of your furnace. However, there are a few generic troubleshooting items you can look at.
First, does this occur while you are connected to shoreline power or dry camping? If you are dry camping, then I would start by looking at the battery to see if it’s fully charged or sulfated. Hooking up a battery booster would determine this right away.
Next, I would look at getting a new thermostat as these are very poorly made and usually have inferior wiring. That could be the issue during cold temperatures. I remember not being able to start the furnace while traveling for Winnebago in 10 degree temperatures. When I called back to tech support they told me it was too cold for the furnace to light! They eventually fixed the problem with proper gauge wiring. You might even want to replace the thermostat with a newer model.
Altitude could be an issue
Another issue could be altitude, as the mixture would be difficult to light. If you are in the mountains when this happens I would recommend contacting the Original Equipment Manufacturer (OEM) to see if they have an optional orifice for higher altitudes.
Have your furnace properly serviced. That means they would take the unit out and clean the burner assembly, intake, and manifold. All this is inside the furnace and can affect the airflow and fuel ratio. At this time, they would also check the motor and fan—which are probably what is making the noise.
It also could be bearings in the motor or a broken piece of the fan or squirrel cage. The unit should not be that noisy. This is something you might be able to inspect yourself. However, you would need to remove the unit and take it apart to do so, and need to determine your level of confidence.
Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.
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