On the Level with your Finicky RV Furnace

Of all the appliances in your RV, the propane furnace will take the cake for acting badly. There are so many things that can go wrong, not only with the furnace itself but with all of the support systems that feed it. Propane gas pressure, electric voltage supply, air ducting (both intake and output), and thermostat signals can all act up to defeat the perfectly operational furnace without so much as giving a single clue to the camper.

Some simple RV furnace diagnostic calculations - thanks NASA!

And there is one more thing that can put the evil eye on your furnace. But if I told you that now you wouldn’t read through to the end, would you?

If you are the type to take diagnosis into your own hands instead of forking over fistfuls of hundred dollar bills to the mobile RV repair service, then you know the value (and satisfaction) of having a few (or maybe more than a few) proper tools. For diagnosing furnace problems you will need:

• A digital multimeter, a good one can be bought for about $20 in any home supply warehouse or hardware store, for reading voltage supplied to the furnace controls (Note: the stick-your-tongue-on-the-electrical-contacts method isn’t accurate enough)

• A good flashlight, furnace stuff is generally buried deep in the RV interior

• A manometer for measuring the static and operational propane gas pressure in your rig – don’t buy an expensive digital one, build your own to get perfectly accurate results for less than $10 (see http://www.campersmotorhomesonline.com/manometer for simple instructions with pictures)

• The usual small handful of screwdrivers and nut drivers, for removing Philips and hex headed screws

• A small torpedo level: you can buy one at Home Depot for $3, or you can buy an iPhone and download the “Spirit Level” app ($450), your choice
  

  The trusty Torpedo Level

You might not be too surprised at the first 5 items (well, maybe the manometer, but trust me it’s indispensable), but a torpedo level? Yes. After carefully logging the performance of my furnace for 6 months and observing that it really never quite behaved the same at any given RV park, I began to look back at what was different about each RV park and how that might contribute to furnace performance. Temperature, humidity, cold night and warm day versus cold night and cold day. Was the propane full or nearing empty? Had I just switched to a new propane tank? Nothing seemed to stand out as a protagonist. And then it hit me. Each time we dock the rig I level it up. Usually I use the “Good Enough for Government Work” standard and get it reasonably close to level. But on those few occasions where all the right parts of the universe lined up and the rig ended up perfectly level, the furnace worked just fine. On this last setup I left the rig listing just a slight bit to port and just an inch nose-down. The furnace refused to light, even after 2 days and many tries. So I re-setup the rig, adding just a little bit to the port side and a little more elevation to the nose until my torpedo level read dead-on both laterally and bow-to-stern. Bingo! The furnace fired right up! I’m not quite sure why yet, but maybe after a little more studying of the technical manual I might actually be able to figure out how even just a little out-of-kilter can make the furnace finicky. And I’ll be paying a whole lot more attention to leveling during the winter months!

Now, let’s let Tippy have HIS word!