Furnace

[jbwilli1]

Last nite was cold for Texas & the heater decides to go out!


Working fine for the last few days on our trip. Then it starts cycling on & off, starts normal & about 2-3 minutes it shuts down without a cooldown period, then will restart & do the same thing over & over.



None of the ducts kinked, plenty of propane. I changed to a Coleman digital thermostat about 6 months ago. When it cycles off, 2 zeros are visible in the window (for a brief period) instead of temperature settings.


During the cycling the fridge display lit up, one of the figures changed to yellow instead of green.


We're about 200 miles from home, so guessing to head home & CW for repair.


Any ideas welcomed, that might save the trip.


Thanx
JB

[MJC62]

Did you save the old analog thermostat? If so do you have it available in the MH and can you change put it back in to make sure the issue isn't the new thermostat.

[jbwilli1]

I do, I'll try that in the morning. Thanx!

[16ACE27]

Fridge and furnace both run off 12 VDC. What's the status of your 12 VDC system? Batteries charged?

[TurnerFam]

sounds like a battery issue, maybe a low battery cell within one of your HOUSE batteries, which is what powers the furnace and fridge. The furnace igniter and fan both need the 12v power to start and run.

[mcr1010]

If you can't get the furnace running, head over to the nearest store and buy a elec. space heater. We very seldom use the furnace and have a couple of little elec. heaters to knock the chill off and keep the coach comfortable on those really cold nights. Just returned from a west coast trip and some of the higher elev. were down in the upper 20's.

[jbwilli1]

12 volt system is fine, all other appliances work normal.



Changed back to original thermostat, worked ok on first use, next time it cycled on same troubles.


Wondering if it's like a thermal limiter causing this. I carry a portable electric that helped a little, buying another today.



It's a Dometic DFMD35151

[jbwilli1]

Looked at my my Progressive industries smart surge protector SSP50XL & it shows open neutral. Could this be a cause of the heater malfunctioning?



Is it a bad thing?

[nosticks]

Originally Posted by jbwilli1

Looked at my my Progressive industries smart surge protector SSP50XL & it shows open neutral. Could this be a cause of the heater malfunctioning?

No. Heater runs on 12v.

[lwmcguire]

Originally Posted by jbwilli1

Looked at my my Progressive industries smart surge protector SSP50XL & it shows open neutral. Could this be a cause of the heater malfunctioning?



Is it a bad thing?

Open NEUTRAL is a really bad thing

You need to get that checked out

It isn't safe to be plugged in until that is rectified

[jbwilli1]

Campground checked the pedestal & all is good. He said the surge protectors fail often. I took mine to 2 empty spots to see if I got the same results, which I did.


Got home 2day, plugged it in & it's probably the surge protector.


Thanx to all for the help & advice!!

[MJC62]

Did you get the furnace back online?

[jbwilli1]

No, it must be something in the furnace, I changed the thermostat & the furnace won't cycle as it should. A/C is on thermostat, it works fine.


CW is swamped & we have another trip planned in a few days, so I'll take it in next Monday.


I'll post the findings then.

[taylorbob1]

Buy a can of compressed air and blow everything inside the furnace door
Then do it again
(Be careful not to allow excessive moisture to expel from the can compressed air)

You may need to dis-assemble the igniter, clean out
Or
The problem is in the mother-board

It’s very frustrating when this happens and CW generally replaces several parts.

[16ACE27]

Originally Posted by jbwilli1

Last nite was cold for Texas & the heater decides to go out!


Working fine for the last few days on our trip. Then it starts cycling on & off, starts normal & about 2-3 minutes it shuts down without a cooldown period, then will restart & do the same thing over & over.



None of the ducts kinked, plenty of propane. I changed to a Coleman digital thermostat about 6 months ago. When it cycles off, 2 zeros are visible in the window (for a brief period) instead of temperature settings.


During the cycling the fridge display lit up, one of the figures changed to yellow instead of green.


We're about 200 miles from home, so guessing to head home & CW for repair.


Any ideas welcomed, that might save the trip.


Thanx
JB

Originally Posted by jbwilli1

12 volt system is fine, all other appliances work normal.



Changed back to original thermostat, worked ok on first use, next time it cycled on same troubles.


Wondering if it's like a thermal limiter causing this. I carry a portable electric that helped a little, buying another today.



It's a Dometic DFMD35151

The furnace supplies 12 VDC power to the Thermostat. Sometimes the fridge control power runs off the same circuit as the furnace.

If you have a bad control board in the furnace it may be temporarily drawing enough current to cause a sufficient to drop the voltage to the thermostat to initialize the display (00) and freak out the fridge controls. Bad control boards are common in these furnaces, if you replace it I highly recommend a Dinosaur control board which has a 3 year warranty and is a better product.

[abjbrtd]

+1 for Dinosaur

If you can change your thermostat you can change the circuit board, it's easier to do, take lots of pictures.

Here is a forum thread that will help. Post #9 has a picture of a furnace/circuit board.
4 screws gets the cover off
4 small screws holds the board in.
Look at the bottom of the board if you see any colors besides green and silver (corrosion is rusty looking) you've found your trouble.
https://www.thorforums.com/forums/f8...sue-20083.html

This is a link to Dinosaur.
https://www.dinosaurelectronics.com

Post #4 is a picture of our circuit board.
https://www.thorforums.com/forums/f8...off-19066.html

[jbwilli1]

UPDATE on the surge protector. Contacted Progressive Industries who is sending a replacement under their lifetime warranty!



I bought a second heater, but with both on it trips the 15A breaker.


The schematics are like looking at scribble, to me.


Are all the 110V outlets on same circuit or is there another I can use the 2nd heater on.


Still have 4 more days until we get home.

[TurnerFam]

you have at least TWO separate 'general and gfci' outlet circuits, easily handling 2 electric space heaters on each, IF you are not running them on 1500w power, but on 750w(low) each, and as long as you don't have many other things that are plugged in running.

Your microwave is on it's own circuit... but remember that your residential fridge, if you have one, will be on the 'general recepts' circuit, along with other general outlets.

I'm doing it now as we speak....

[TurnerFam]

750w 'low' electric heater running equates to about 6.25amps each, leaving another 13.75amps for the rest of the circuit

two on the same circuit running would still only be about 12.5amps total, still leaving available amps for other smaller items, like TVs, receivers, device chargers, etc, none of which use too much.


now, since you are a 30amp RV, your TOTAL usage can't exceed that, even if the individual circuits themselves can - make sure you are aware of your other silent 'users', such as the convert's battery charger, the electric water heater element, etc.

[jbwilli1]

This should be a 50A unless you see something different.


Attached are 2 photos of the circuit board, the door was well sealed & inside dry.


Best I can see is 2 screws holding it in one on right & one deep inside. Circuit board is mounted upside down? maybe to keep water from pooling?


You guys are the best, I'm getting smarter on this rig everyday!!!