RV Furnace Troubleshooting Tips and System Overview

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Duration: 8:35

There’s not a ton of maintenance required on an RV furnace, which operates similarly to the furnace in your home. However, there are things you can do to make it run more efficiently and to troubleshoot if you experience any issues. Say for instance, what should happen when the furnace on a 2003 Winnebago Brave, which runs off of liquid propane, starts to experience issues? How does one go about completing RV furnace troubleshooting to diagnose and solve a problem?

In this in-depth video lesson, RV maintenance and repair expert Dave Solberg teaches you about RV furnace troubleshooting. To give you a better understanding of maintaining a furnace, he begins by explaining how the furnace operates, component by component. You’ll learn what happens from the moment the fan kicks on because the thermostat calls for heat until the end of the line when the thermostat recognizes that the input temperature has been met.

Start with the fan: laying the RV furnace troubleshooting groundwork

Dave begins with the basics of RV furnace troubleshooting. He emphasizes that it’s important to note that the furnace on your RV works by drawing air from the inside and heating in, rather than pulling in outside air to heat.

A mounted thermocouple on the backside of the furnace senses when the furnace is getting too hot and automatically shuts the system down. Good airflow guarantees that the furnace doesn’t overheat, and proper flow is necessary in every system, whether it utilizes a plenum or corrugated hoses (AKA elephant trunk ducts).

To ensure optimal airflow, you should always avoid blocking vents with area rugs and piling objects on or near corrugated hoses. It might not seem like a big deal at first, but putting weight on the hoses can pinch them and restrict airflow, which results in an inefficient or often unresponsive heating system.

How to: troubleshooting step by step

What you need to check if your unit isn’t running, according to Dave: firstly you need at least 10.5 V, so if your battery is sulfated the LP system might start up but won’t run for too long. The fan won’t spin fast enough to lift the sail switch and get heat flowing. However, when the sail switch drops, that doesn’t stop the fan from spinning, which can deceive RVers who think the heat should be coming if the fan is in motion. If this is the case for your furnace, your battery likely isn’t producing enough voltage to lift the sail switch.

Take Dave’s advice into account, and see if you can solve your RV furnace troubles. If you need further help, feel free to leave us a comment or send an email!

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24 Responses to “RV Furnace Troubleshooting Tips and System Overview”

    • Customer Service
      Customer Service

      Hello Robert. It really depends on all the symptoms you are having and what the furnace is doing. If the furnace kicks on and then runs for a few minutes without starting the ignition, then there is either an air flow restriction or an issue with the sail switch inside the fan housing. The fan could be broken, motor running slow, low voltage or blocked exhaust will cause this. If the furnace doesn’t run at all it could be a voltage loss, blown fuse, bad thermostat or failed control board. The most common issue for furnace ignition failure is the sail switch. There can be dirt or debris on it and there are many models that have switches fail every so often. I have replaced many of these. The best thing to do is gain access to the sail switch on the fan housing, remove it from the housing, start the furnace and press the switch. If it works, then there is something else causing the issue like low air flow. If the furnace still doesn’t work then the switch is bad and needs replaced.
      Dan
      RV Repair Club

      Reply
  1. Genelaprise
    Genelaprise

    Hi we have a rev second hand; that repaired the heater . It work the air gets out and we have a little air warm but not like before we checked and we don’t know yo do check now to have more heat because it start et goes 1/2 hour and we a 2 or 3 degrees more that it!

    Reply
    • Customer Service
      Customer Service

      Great question! The ‘Ask an Expert’ section is currently for members of our online community. I would be happy to send your question off to the experts. To get started, please send the email associated with your paid membership account. Thanks!

      Reply
  2. Allison
    Allison

    We have a 2015 Crossroads Trailer – model Maple Country…1) furnace is not under that outside vent panel….where is it and 2) can changing our battery on trailer from 12V to two 6V batteries cause furnace to stop blowing hot air

    Reply
    • Customer Service
      Customer Service

      Hello Allison,
      Here’s what the experts had to say about your question:
      The furnace is directly behind the exhaust vent on the outside. There are many different model Maple Country’s and they are all in different locations so it is best to find the exhaust on the outside and know where to look on the inside. There should be a return vent on the inside and the furnace will be directly behind that. Hooking up 6v batteries shouldn’t cause an issue unless they weren’t connected properly. They need to be connected in series to create the 12v needed to operate everything. Having them hooked up wrong will cause everything else not to work as well, not just the furnace. If the furnace kicks on but just doesn’t blow hot air there could be many things wrong. Low voltage could cause the fan to not run fast enough but if the voltage was this low, other things wouldn’t work as well. There could be an issue with the fan, sail switch, control board, gas valve, igniter or limit switch. There could also be a blockage in the exhaust or something else preventing the fan from running fast enough. The fan has to run a certain speed before the ignition cycle even starts so air flow is very important. We do have many issues offering troubleshooting tips on furnace issues.
      https://www.rvrepairclub.com/?s=furnace

      Sincerely,
      Dan
      RV Repair Club Technical Expert

      Reply
  3. Daryl Eide
    Daryl Eide

    My heater and A/C will not come on. I have replaced the converter box on the main A/C unit. Mine is a 2010 Montana with duel A/C. My control panel is lit up but neither one will come on. I have checked all fuses

    Reply
    • Customer Service
      Customer Service

      Hello Daryl,

      Thank you for contacting us.

      Since the control box in the AC was replaced the only other common component used for both heat and AC would be the thermostat. They do all share the same 12v and if there was an issue with the control box on the AC it will prevent the furnace from working but since that was already replaced it points more towards the thermostat being the issue. If there was a voltage issue the thermostat most likely wouldn’t light up because it is all shared between them all. I would check all connections on the back of the thermostat control panel, at the AC and at the furnace to double check that nothing is loose but from what I have seen in the past the thermostat causes this to happen.

      If you have any other concerns, please contact us at 1-855-706-3536, or chat with us on our site.

      We greatly appreciate your business!

      Sincerely,

      Lindsay
      RV Repair Club Video Membership

      Reply
  4. Daryl Eide
    Daryl Eide

    My heater and A/C will not come on. I have replaced the converter box on the main A/C unit. Mine is a 2010 Montana with duel A/C. My control panel is lit up but neither one will come on. I have checked all fuses

    Reply
    • Customer Service
      Customer Service

      Hello Daryl,

      Thank you for contacting us.

      Since the control box in the AC was replaced the only other common component used for both heat and AC would be the thermostat. They do all share the same 12v and if there was an issue with the control box on the AC it will prevent the furnace from working but since that was already replaced it points more towards the thermostat being the issue. If there was a voltage issue the thermostat most likely wouldn’t light up because it is all shared between them all. I would check all connections on the back of the thermostat control panel, at the AC and at the furnace to double check that nothing is loose but from what I have seen in the past the thermostat causes this to happen.

      If you have any other concerns, please contact us at 1-855-706-3536, or chat with us on our site.

      We greatly appreciate your business!

      Sincerely,

      Lindsay
      RV Repair Club Video Membership

      Reply
  5. Steve Bomgardner
    Steve Bomgardner

    My fan goes on for 20-30 seconds then stops. Propane bottles are full and all other systems work. No igniter clicking heard. Control board?

    Reply
    • Customer Service
      Customer Service

      Hello Steve,

      What is the year, make, and model or your RV?

      If you have any other concerns, please contact us at 1-855-706-3536, or chat with us on our site.

      We greatly appreciate your business!

      Sincerely,

      Sarah
      RV Repair Club Video Membership

      Reply
        • Customer Service
          Customer Service

          Hello Steve,

          Thank you for contacting us.

          Most often this is the fault of a bad sail switch. This is was proves that air is flowing through the furnace before igniting. If the switch is bad or there is not enough air flow then the fan will blow just for a little bit and then shut off. This switch is on the furnace fan wheel housing with two wires going to it. Often the switch can have dirt or debris build up on it or the fan wheel could be broken as well but lately there have been a lot of bad sail switches being produced so there is a good chance that is the issue.

          If you have any other concerns, please contact us at 1-855-706-3536, or chat with us on our site.

          We greatly appreciate your business!

          Sincerely,

          Sarah
          RV Repair Club Video Membership

          Reply
  6. Chris R Kottmann
    Chris R Kottmann

    Our furnace just stopped coming on no fan starting or anything . I tried changing the thermostat out and it worked for about a week then stopped again. Any ideas?

    Reply
  7. Stephen Raphael
    Stephen Raphael

    Hi, I have a 2005 National Tropical T396. In Zone 1, I have 1 heat register under the refrigerator and it blows strong and hot air. But I also have 2 heat registers”Elephant trunk” that come from under the passenger side Sofa. 1 works great (near kitchen) but the one nearest the passenger seat just suddenly stopped blowing when the furnace is on. The conduit to the working register is warm to the touch but the other conduit is cool to the touch. In Zone 2, the register located under the sink in the bedroom blows hot air but the register on the toilet pedestal in bathroom is Barely blowing warm-ish air… Im not certain where the ducts run in Zone 2 so I can’t see if they’re ” pinched” . In Zone 1 I can see the ducts under the sofa until they disappear under the kitchen sink cabinet, but again , don’t know where they go from there. This issue is ( 2 out of the five registers not operating correctly) appears as though is starting to make the furnace ” Short Cycle” duration of intervals is approx 5 to 7 minutes…all night. Please help me. (Please email response to me at stephen.raphael@gmail.com) I’m in my 60s and have a hard time navigating around the site to get back to the right thread. Thank you

    Reply
    • Customer Service
      Customer Service

      Hello,

      Here is the expert’s response:

      The best thing to do is to gain access to the furnace directly. The ducts attach to the side of the furnace and if some fall off, it can create this issue. It is more common for ducts to come off the furnace directly rather than issues like collapsed duct work. I would start at the furnace and see what it looks like. If everything is fine there, you then have to trace the lines and see if there is a bad connection at a “Y” or something else. These can split off into other areas and these connections can come loose. Most likely the issue is at the furnace though.
      Sincerely, Dan RV Repair Club Technical Expert

      Reply
      • Stephen Raphael
        Stephen Raphael

        Dan,
        Thank you very much. The furnace for zone 1 is under cabinet of kitchen sink. And that appears to be where the “Y” for the elephant trucks that feed the couch are located. But I have to remove the floor of the cabinet under the kitchen sink. My next step.
        Zone 2 furnace ” appears” to be beneath the cabinet that would house the washer / dryer combo if I had one. The fresh are return is in this area too. When I removed the dresser drawers next to the return I found enough of the previous owners clothing that had overflowed from the drawers and hamper to fill a 13 gallon kitchen trash bag more than half way! I am surprised there was any airflow !!! After removing the items of clothing, the furnace heat registers really began to blow!!! And NO short cycling!
        Thank you again so very, very much. Dan, I’m a newbie and your advice and videos are EXCELLENT

        Reply
  8. Robert Mackie
    Robert Mackie

    furnace runs for 10-15 seconds and then shuts off, then it comes back on 15- 20 seconds later

    Reply
    • Customer Service
      Customer Service

      Great question! The ‘Ask an Expert’ section is currently for members of our online community. By becoming a member, you will have access to our expert knowledge. With your membership you will also receive discounts on products and hundreds of hours of Premium content.

      If you are interested in becoming a member, please click on the offer below:
      https://go.rvrepairclub.com/C41240
      Thanks!

      Reply