Furnace ignites when cold?

[Randallt]

Hi folks. My 23 Bullet’s furnace seems to fire up randomly in the middle of the night when it’s very cold out. The inside heater doesn’t kick in, but I can hear the faint noise of the flame igniting from my bed and then it runs for 30 seconds or so. I have a tankless water heater so I am guessing the system is just being helpful so pipes don’t freeze? I’m new to camping and knowledge of this camper’s systems is still somewhat limited. Thanks so much.

[JRTJH]

I'd suspect by now, if the trailer is parked beside the house and you're hearing this from inside the house while in bed, that you haven't winterized the trailer ????

You start by saying the furnace ignites and runs, then move to the water heater.... Have you confirmed which appliance is "running in the middle of the night?

I'd think that if everything is turned off that what you're hearing is the water heater "automatic protection" to keep from damaging the water heater during freezing temperatures.... That's a "risky proposition" given the potentials that could interrupt power to the trailer and disable that feature.... not to mention the good possibility of running out of propane and waking up to a non-functional water heater and maybe even damaged faucets/PEX fittings or even a frozen water pump in the fresh water supply.

If you're not using the trailer, I'd winterize it and if you're planning to use it, just de-winterize and re-winterize after the trip. Heck, just using a compressor to blow out all the lines would be cheaper than propane and electricity to keep it "warm and thawed" ....

[Randallt]

I am living in the trailer full time. I have shore power and am connected directly to a septic tank. I have insulated well, around and beneath, and have created a heated and insulated “city” water intake system, most of it buried. This only happens when the temp outside is in the lower 20’s. I was leaning towards the “auto protection” idea as well, so thanks for that.

[JRTJH]

Originally Posted by Randallt

I am living in the trailer full time. I have shore power and am connected directly to a septic tank. I have insulated well, around and beneath, and have created a heated and insulated “city” water intake system, most of it buried. This only happens when the temp outside is in the lower 20’s. I was leaning towards the “auto protection” idea as well, so thanks for that.

Ahhh That changes the "living arrangements" significantly....

Your furnace should run to keep the trailer warm, both in the cabin and also in the belly, where much of the water plumbing and the tanks is located. You said that you have a "propane demand water heater" and some of them do have a "freeze protection circuit" that fires the propane to warm the heater, preventing freeze damage.

If you have inside access to the back of the water heater, you might benefit from opening that access at night so warm "cabin air" can help warm the back of the water heater. When we "cold camp" we also open the cabinets under the sinks and any that have plumbing runs in them to help prevent frozen pipes in the trailer. Most of the plumbing runs are near the bottom of the trailer sidewalls, so they are "closest to the coldest parts of the trailer structure.

[wiredgeorge]

Perhaps drop cords with 75W incandescent bulbs under the sink and water heater makes some sense? I keep drop cords handy as I sometimes don't winterize in the winter here in S. TX. since it seldom goes sub 32F for long BUT once in awhile we get prolonged cold snaps. I don't have an insulated bottom but do keep the tanks drained in the event there are freezes.

[Randallt]

No inside access, but I see your point. I could at least thinly insulate the heater compartment. I read that here I think when I was just getting started with this camping experiment this summer. I had forgotten all about that, thanks. And thanks for confirming my thoughts that there is a freeze protection circuit. Awesome that this little guy has this.

[Randallt]

I should prepare for that when it gets really cold. We see a few 2º-9º occasionally. The undercarriage is closed in nicely and I spent some time this fall under there tweaking a few gaps. Thanks for the reply.