Furnace not working at altitude

[LG Matson]

Just picked up a 19' this August. Have made a couple of trips up into the Colorado mountains but our furnace doesn't work. Blower comes on but only cold air. Wonder about the thermostat. Seems sketchy. But furnace works at home at about 4800'. So they tell me that it doesn't work over 5500'. We have camped at about 8000 both times. Fridge and stove work fine on propane but not furnace. Anyone else experience this? Wondering if there are any modifications we could make.

[Illinois Joe]

I've done a fair amount of camping in mountains and never had an issue with the furnace running in any of my RVs. I did have a 3 way fridge that had problems lighting at high altitudes and cold temperatures (e.g. below 45F). A service tech adjusted the sparker and it was better but never 100%. He also showed me how to light it manually when the sparker failed to light it. Not sure this helps much except to say that maybe someone knowledgeable with the furnace and high altitudes could recommend a solution.

[fudge_brownie]

Easy to test the thermostat, just short the two wire coming to it. Be sure the stove works as a test. Switch propane tanks. Replace the propane regulator.

[Nigel]

I’ve heard stories of people having their propane tanks filled in the south and then having issue when coming back north to the cold weather. Apparently they were getting filled with butane and stays liquid below 31 degrees f. This was twenty years ago, I don’t know if this is still a thing.

Nigel

[DanandDaphne]

That's rediculous that they say it's not supposed to work over 5,500 ft that's pretty low expectations they have set for themselves.

We live at 8,800 and our furnace works fine.

Even though your other appliances work fine it's likely your propane regulator. It is adjustable but you may just want to try replacing it with one of these https://www.amazon.com/gp/product/B0...KIKX0DER&psc=1

They are said to be better than the one that comes on our escapes.

[alanmalk]

Originally Posted by LG Matson

Just picked up a 19' this August. Have made a couple of trips up into the Colorado mountains but our furnace doesn't work. Blower comes on but only cold air. Wonder about the thermostat. Seems sketchy. But furnace works at home at about 4800'. So they tell me that it doesn't work over 5500'. We have camped at about 8000 both times. Fridge and stove work fine on propane but not furnace. Anyone else experience this? Wondering if there are any modifications we could make.

By the process of elimination: If the furnace works at home then the thermostat is fine. It is not altitude sensitive and the blower would not function if the thermostat didn't call for heat.

The next suspect is the sail switch. Working at home but not at altitude? Call that an unlikely "maybe". They are notorious for causing grief but somewhat painful to swap out but cheap enough if you do it yourself. Lets save that one.

Gas pressure in the tank? Well, if your stove works on all burners at the same time, and your water heater is heating, also at the same time (listen for the roar), then the tank(s) are likely OK.

Gas pressure in the line? Another suspect. Yes, running all appliances at the same time gives a reasonable indication. But it is very easy to check - or very inexpensive for a serviceman to check with a meter. Should only take minutes. Perhaps start there and if the pressure doesn't meet specifications then a new regulator may be in order. Some regulators may be adjustable but I don't know specifics.

For the record, we have camped at 9000+ without issues.
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Alan