furnace failed AGAIN

[louwho99]

It's 4:30am, outside temperature is minus 5 & the furnace has failed again. Down to 57 degrees in the RV. We have space heaters going but can't get it any warmer.
We've been in this 2008 MS for 3 years & every winter the furnace stops working. Every time it fails, we replace the mother board & it starts working again.
The furnace failed 1 month ago, so bought another new mother board. The furnace worked for a month. And now it's failed again.
Before we freeze to death, does anyone have any ideas as to what the problem really is with this furnace? Having the board continually fail can't be normal.
I appreciate your thoughts about this.

Cindy
2008 MS 38RLSB3

[billr]

Have the gas flow checked. The furnace is a heavy user and it may be on the low edge of the tolerance. It takes a few min for an RV tech to do. The regulator may need to be replaced. This is what we had to do several years ago with a intermittent furnace.

New regulator is not too much $.

Bill

[01zeosix]

I agree with Bill. Had the same problem with mine. Replaced the regulator. Problem fixed.

Hope this helps.

[golf_bears]

Are you talking about the regulator in the propane tank bay or some other regulator in line to the furnace?

Good info to know if and when we run into the same problem.

Not sure if this will help but had a similar problem recently during our stay in MI over the Thanksgiving holiday. Temps got down into the teens overnight. The furnace stopped working so I figured the propane tank was empty. Went out to check, gauge was still showing green. Switched over to the second tank and furnace fired up. The tank I switched from had a frost line about 14" up which surprised me. Had the tank filled and it took 7.5 gallons which also surprised me.

I figured cold temps lowered the pressure in the tank and gas would not flow out. Funny things happen when your on the road in cold temps.

[billr]

Tank Regulator

[terry and jo]

Are you talking about the regulator in the propane tank bay or some other regulator in line to the furnace?

Good info to know if and when we run into the same problem.

Not sure if this will help but had a similar problem recently during our stay in MI over the Thanksgiving holiday. Temps got down into the teens overnight. The furnace stopped working so I figured the propane tank was empty. Went out to check, gauge was still showing green. Switched over to the second tank and furnace fired up. The tank I switched from had a frost line about 14" up which surprised me. Had the tank filled and it took 7.5 gallons which also surprised me.

I figured cold temps lowered the pressure in the tank and gas would not flow out. Funny things happen when your on the road in cold temps.

It wouldn't have been the temperature lowering the pressure unless the gas was butane instead of propane. I used to haul and deliver both products back years ago and always had to go around to butane tanks and inject a bit of propane to increase the pressure. Butane is REALLY subject to cold, but it REALLY has to get cold to stop propane.

Terry

[louwho99]

Thank you all for your suggestions. My husband did check everything & found a loose connection. Tightened it, hoping that the furnace would work, but it didn't. So we purchased another mother board, installed it, made sure all connections were tight & the furnace is working again.


Cindy

[01zeosix]

Glad you got it fixed!!! Nothing worse than being cold at this time of year. (Except, may e, bing froze up.)

[golf_bears]

Terry,

Thanks for sharing that info on propane vs. butane. Perhaps it was the regulator giving me problems?

We're in an area now where temps are in the high 20s low 30s and are not experiencing any issues with the furnace or the propane. Maybe I'll have the regulator checked out when we get to our winter destination in the RGV.

[billr]

Yes, good to have things running again! Strange another board, but they can go thats for sure.

Cold weather camping can be a real challenge.

Bill

[Motor31]

If the mother board keeps failing it sounds like there is an issue with possible surges in power. A spike or drop in power may be taking the board out. Given that the furnace is 12 volts my guess would be power drop more than a spike since the battery and converter "should" buffer any voltage fluctuations. I would check for wiring issues and any loose / dirty connections and voltage levels at the power feed to the board.

[Okie]

Cindy, Mike is right about the voltage at the input of your furnace board. It should run a little over 13 volts down to 12 volts checked with a digital meter. I can't imagine a low voltage taking out the mother board. I suspect, that in your case with all of the replacements you have had, that there is something wrong with the mounting of the mother board and it is being cracked when you are moving on the road. All it takes is a very small crack in the board. And it is out of business. You might not be able to see it. Something to check.

Okie

[Motorcycle Jack]

Also check the 12V supply going into the furnace with your volt meter set on AC. AC getting into a DC board is a culprit most techs will not think of. AC will kill the board quickly (your time frame about right). If you see more than couple hundred millivolts of AC your converter is bad (out near the battery compartment) and needs to be replaced. Also there are services that will rebuild your board rather than buy a new one (I hope you didn't throw them away). Send one to them to have rebuilt and hold onto it if you lose yours - you have one.