furnace thermostat altitude issue

[Helmut]

2017 furnace with electronic thermostat

Hi,
is there a way to ajust the thermostat at high (>12500ft) elevation.

the furnace works perfect. no problem with lighting or heating.
But as soon as I get higher than about 12500 ft it will stop heating at about 66° - no matter how high I set the thermostat (all the way to max). It shuts off and I can restart without problems, but can only get it about 1 or 2 degrees higher.

annybody with a solution?

thanks for the help

Helmut

 

[Wandering Sagebrush]

Good morning Helmut,

I’m puzzled why your furnace would shut down at that temp, but restart with no problem. About the only things I can thing of is trying a manual thermostat, or even bypassing the thermostat by shorting the wires.

Have you contacted the manufacturers of both the furnace and thermostat to see if they can explain what is happening?

 

[ski3pin]

I would try running it with bypassing the thermostat. If the furnace continues to operate, it's the thermostat. If it shuts off - as before - it's the furnace.

 

[Wallowa]

Heck...higher than 12,500 ABSL and breathing not the heater working would be my major concern!

Agree with Ski3Pin....sail switch not the issue as it starts [would have guess air density, but that is not it]...thermostat could be funky...I honestly have never had my Hawk up to 66F...

You never mentioned the outside temp. Could the furnace just not keep up with heat loss to outside? But if that were the problem I doubt it would shut off on its own.

 

[Jack]

This is a good one!

I wouldn't rule out the sail switch. At that elevation the air is much thinner, and heated air is even thinner.

 

[heinphoto]

Try removing the silver ducting just inside the front cover/grate of the furnace inside the camper. There are 2 screws that secure the cover, and the ducting connects from that cover to the furnace - just pull the ducting off both ends. Apparently, the ducting can cause enough back pressure to prevent the sail switch from activating or staying activated. This has solved problems with the furnace at altitude for a number of folks and is something FWC is recommending if you are having problems. Last summer we were camping at ~9000' with friends who also have an FWC. Both our furnaces would start, but then click off after a period of time. I pulled the ducting off both our furnaces and they worked fine after that. It's at least worth a try.

-Scott

 

[Helmut]

Thanks for the answers.

I‘m in the Andes Bolivia at the moment. Will have some nights at about 15000 feet. Already tried to get a mechanical thermostat. Shorting the wires will def tell me what is causing the problem. Sleeping temp are no problem. But we do like it nice and warm while awake. The furnace has handled way lower temp, but that was a couple of years ago. So who knows. I was thinking if the thermostat coul be calibrated somehow. Some of the mechanical ones seem to be. Will find out next week, if the furnace keeps on running when bypassing the thermostat. Also will have a look at the sail switch.

 

[Bigfoot Dave]

Just a guess, at that altitude could the reduced oxygen cause a reduced flame that will produce less heat? Will the furnace run constantly?
Bigfoot Dave

 

[Adventurebound]

If you haven't done so already, remove the ducting. Based on my super scientific calculations from read this forum (and doing the same to fix my 2+ years of furnace issues) this solves 99.9% of all FWC furnace issues.

 

[Helmut]

I‘m back. Spent a night at 14200. First furnace started as normal. Then stopped. Was cooking on two flames at the same time. Finished cooking and the tried to restart the furnace. Tried the stove again, flame normal but then finished. Ran out of propane. Changed the tank. Furnace started and function was normal up to 72 degrees. So this time it was an almost empty propane tank. Last time it was def not empty, but also not full. Never know what you get here, when you refill „propane“, could also be „butane“ or an mixture. Will have the oportunity to check in the next couple of days.
Thanks for the replys. I did bypass the thermostat, but with an empty propane tank

 

[goinoregon]

whatever is the problem with your furnace, good luck - but please keep sending trip reports. i am definitely interested in your trips over 10,000 ft elevation !!