Furnace not working in Casita
 

My furnace was working this morning, now it is is completely dead. And it is 16 degrees outside.

The pilot light is not on, and the fan doesn't start when the thermostat is turned on. The LP hot water heater and LP stove both work, so it has propane. I changed the fuse (#8) to the 15amp spare (#4). This is a 2015 SD17. I've been turning it off for a while, and trying to turn it back on.

Any suggestions? Thank God I have a space heater, or I'd be frozen.

I can feel your pain Bill. No answer for the heater but how about getting an electric blanket ?

Out of propane? Does your stove ignite? Raz

The stove works, and the water heaters works. Both are using propane.

Yea, you said that didn't you. I had an issue with mine a while back. It turned out to be a poor contact in the thermostat.

Sail switch???

Hi Whoot,
I personally don't know what might be going on with your furnace, particularly in light of the case that both your water heater and stove are getting propane and working. However, I went on the Internet and found this information. I'm sure you already know this stuff, but just in case. I found it at a website called "RV Basics."

Wendy


Pilot Light Won't light or stay lit.

Make sure the thermocouple is positioned properly in the pilot flame.

Another common problem is a bad regulator at the propane tank. A simple test will indicate if this is the case. Light all the stove burners and look at the color of the flame. The flames should be blue with little or no yellow color. If the flame does not change color then the regulator is probably working. A bad regulator could also cause problems with your hot water heater.

Note: Most modern RV furnaces have a direct spark ignition system that replaces a pilot light.

Fan doesn't run and no heat.

If the fan will not start you should first check that your battery is good and you have 12 volts at the furnace. You could have a tripped circuit breaker or blown fuse.

If the battery is good and you have electricity to the RV's heater next check the thermostat.

Remove cover and look for the "anticipator" adjustment. (Note: Some new thermostats do not have an anticipator.) It will be an adjustable control with a sliding contact over a straight bare wire or a bare wire wound about an insulating material. If the fan will not start set the temperature to maximum and then move the anticipator slider while listening for the fan to start. Be sure to wait long enough... it normally takes our furnace 30 seconds for the fan to start once the thermostat sends a signal.

If the fan starts after you move the slider then you have probably found the problem. In this case you may find a slider position near the original position that will work reliably. If your thermostat anticipator adjustment uses the straight wire design and the wire lies directly on the plastic housing then you should look to see if the wire has sunk into the plastic. This wire produces heat and causes the plastic to melt a little and the wire to sink into the plastic so the slider no longer makes contact. It may be necessary to replace the thermostat.

Fan runs but no heat.

If your furnace fan starts you can assume that the thermostat is working.

Possible problems are insufficient air flow through the furnace a bad propane valve at the furnace or a bad regulator at the propane tank.

A furnace contains an internal sail switch, that senses the air flow. If the air flow is not sufficient then the switch will prevent the furnace from igniting and the fan will run but you will get no heat. A slow motor speed could be caused by a low battery or other low voltage cause such as a bad connection in the wiring.

Low air flow could also be caused by a restriction in the ventilation system. Check to see if any heat registers are closed or blocked. Some furnaces will not tolerate even a partial closure of a heat register. .

If you have an electronic ignition check to see if the two contacts are touching or are too far apart. They should be about 1/8 apart.

Could it also be possible that there is water vapor in the propane line that leads to the furnace only and that it has frozen there? Also found this...

"Your surmising that there is a line blockage that freezes up in the propane line to the furnace sounds like a good one. Both water and oil can get into the line and cause this sort of problem. Since other appliances continue to work, it sounds as though the blockage is fairly close to the furnace. The usual fix is to disconnect the line at both ends and blow it out with compressed air. However, a good pair of lungs is sometimes sufficient to huff & puff it out (don't inhale the propane though!). And if you can get the line oriented right with no low spots, it might even drain out on its own if left a couple hours."

Perhaps, Whoot, if you warm up the trailer with the electric heater, even going so far as to direct the heater toward the furnace, opening up the little cupboard near it, it might thaw out. Just another idea.

Wishing you well,
Wendy

OK, here is a gotcha! In the storage cabinet by the heater, there is a rocker switch on the left side 1/2 way inside. When putting things in this storage cabinet the switch can get turned off. This happened to us. Check the rocker switch.

If you have no pilot there can only be two causes -
1]no propane reaching the unit
2]faulty thermocouple

If your trailer is a 2015, then the furnace should still be under warranty. I would contact the manufacturer to find out how to get warranty repair. Their customer service may be able to answer your question and offer a fix.

Take the cover off the thermostat and jumper the two terminals together.
See if the furnace tries to start / fan runs
If fan starts check the sail switch. On a friend furnace I ran two wires off the sail switch to an accessible location so it was easy to test if the sail switch was closing when the fan was activated .

Can say without a doubt you do not have a pilot light in a 2015 furnace. It has electronic ignition.

Normal sequence of events when thermostat turns on:
1. Fan starts
2. Sail switch activates.
3. Gas on and ignition.

If the fan doesn't start nothing else will happen. Either the thermostat isn't working correctly or there is something wrong in the thermostat to fan circuit.

As stated by someone else the first and easiest place to start is the thermostat. Take the cover off and short out the contacts. If the fan doesn't start you'll need a volt meter to start looking for the break in the thermostat-to-fan circuit.

If the fan starts keep the short on and wait for ignition (it will take a few - maybe 5 or 10 - seconds).
1. If you get ignition replace (or fix if possible) the thermostat.
2. If it doesn't ignite in a few seconds but you can hear the igniter snapping (it's an electrical spark) you've probably got a gas problem - maybe the gas solenoid valve.
3. If it doesn't ignite and you don't hear the igniter it is probably either a sail switch problem or the igniter itself.

In either case 2 or 3 you need to find someone who knows how to check out the problem in detail.

Good luck.

Is there water inside the burn chamber? It can get in theough the freash air and exhaust inlets.

My 2013 Casita's furnace has no pilot light and employs direct spark ignition. I would check first for the two most obvious furnace requirements fuel & 12 VDC power.

The furnace is now working. The contacts in the thermostat, which turn on the furnace, needed sanding to remove some kind of residue.

These are the contacts inside the thermostat on the top left. I'm surprised after just a few weeks of use they needed cleaning, though I have been in the Casita for several months before I ever turned on the furnace. I had fiddled with the contacts before, but they looked very clean. I guess there was some kind of build-up I couldn't see.

Thanks for all the help, and I'm glad it wasn't anything serious. It's scary having things stop working when it is below freezing.

Maybe time for a digital thermostat mod. Glad you got it working!

I have a digital thermostat in my Casita and slide in camper.
When winter camping I have a good sleeping bag and a down comforter so I really don't need the furnace at night.
It sure is great to have it come on automatically at 6:30 am though.

oh my god

Hi,
I have had this problem before and everyone on the Casita forum told me to check my battery. I thought they were crazy. I had the same symptoms as you. Finally checked the battery and that was the problem. If battery is too low the furnace will not come on. No fan, no propane. First thing is to check your vent for mud wasp nest or the like. If this is clogged, no fan no propane. Good Luck,
Judy