trouble with suburban furnace

[wayne.yl]

This weekend we took the trailer out and had to use the furnace.
It ran fine the first night but on the 2nd night I noticed the fan coming on and then going off immediately. When I set the thermostat to a warmer setting the fan would come on and stay on until the cycle was complete. Any thoughts why I needed to adjust the thermostat to a warmer position before it would work right?
Thanks
Wayne

[lewster]

Originally Posted by wayne.yl

This weekend we took the trailer out and had to use the furnace.
It ran fine the first night but on the 2nd night I noticed the fan coming on and then going off immediately. When I set the thermostat to a warmer setting the fan would come on and stay on until the cycle was complete. Any thoughts why I needed to adjust the thermostat to a warmer position before it would work right?


Thanks
Wayne

Wayne,

Might be a problem with your thermostat or the igniter board of the furnace. I would check the t/stat first as this is far cheaper to replace than the board.

Remove the t/stat from the wall and find the 2 blue wires. Connect them together and see what happens. If the furnace comes on and heats, and stays on until you disconnect the wires, your board is probably OK and the t/stat should be replaced. If not, then it's probably the board.

If you do need a board, I strongly recommend getting a Dinosaur UIB small for your furnace. They are the BEST and have a 3 year warranty.

[wayne.yl]

Lew,
I just finished reading your comments on the other Suburban thread about the Thermostat blue wires. Thanks for helping out.
I will check it out and let you know.

[wayne.yl]

Lew,
The test went fine. I disconnected the two blue wires and pigtailed them together. the Furnace came on, heated up and stayed on until I disconnected the blue wires.
I will replace the thermostat and see if this corrects the problem.
thanks again for diagnosing this issue.
Wayne
PS... are there better thermostats than others?

[lewster]

Originally Posted by wayne.yl

Lew,
The test went fine. I disconnected the two blue wires and pigtailed them together. the Furnace came on, heated up and stayed on until I disconnected the blue wires.
I will replace the thermostat and see if this corrects the problem.
thanks again for diagnosing this issue.
Wayne
PS... are there better thermostats than others?

There are better ones out there, but they are generally not compatible with the RV-type furnace, as most of the domestic systems work on AC rather than DC current. There are electronic versions, but they require a compatible air conditioner, as the control board of the A/C unit actually controls the furnace as well (convoluted I know, but that's how the design goes).

They are pretty cheap, so I would just replace it and not worry until it goes south again. At least it's accessible!!!

[RBolton]

I'll jump in here with a thermostat question rather than starting a new thread.

The thermostat on my 75 Argosy looks to be the original . It does not seem to have an off position. If I set it at its lowest, far left position, the furnace will come on when the trailer temp reaches 55 degrees or so.

I place a small piece of cardboard between the contacts in the thermostat to prevent it from coming on. I guess I could wire in a switch, but it looks like there should already be a way to turn this off. Any Suggestions?

Roger

[PizzaChop]

The thermostat on my 75 Argosy looks to be the original

Any Suggestions?

New furnaces usually come with new thermostats.

[RBolton]

Yes, and I suppose a new trailer would be the easiest way to get the new furnace.

I don't know what I said to warrant what seems like a smart aleck reply. I don't believe a new furnace is the answer. The furnace works great. I was only inquiring as to whether or not this is the proper operation of the original thermostat in that it does not have an "off" position or if I am overlooking something.

Thanks in advance for a helpful response, Roger

[lewster]

Originally Posted by RBolton

Yes, and I suppose a new trailer would be the easiest way to get the new furnace.

I don't know what I said to warrant what seems like a smart aleck reply. I don't believe a new furnace is the answer. The furnace works great. I was only inquiring as to whether or not this is the proper operation of the original thermostat in that it does not have an "off" position or if I am overlooking something.

Thanks in advance for a helpful response, Roger

Roger, The new t/stats all have an on/off switch. You have several choices like White/Rogers, Atwood, Suburban and probably a few off brands. Your local RV Parts supplier should have them and they should be a direct replacement for your original.....$20-30 and you're good to go!

[PizzaChop]

RBolton,

My deepest and sincerest apologies for the offense. It was with lightness of heart, not smart aleckness that I responded to your inquiry.

I'm sorry that it didn't seem that way.

I have replaced two 70s era furnaces and have seen the inside of them.

I have a neighbor who passed away 3 years ago from a faulty RV furnace and there was a recent thread with a link to an article of a couple and their grandchildren who died in a horse trailer from CO poisoning as well.

When I first removed my furnace and took it to the local RV shop, they attempted to fix it (had a bad/leaky valve) and even spoke with Suburban about it, when they were instructed to pitch the furnace, as it was over 30 years old anyway.

I took their advice.

From here on, I'll keep my thoughts to myself.

Best of luck with your thermostat...I never did put the new one in which came with the new furnace, but I think I should've have, as I'm not sure it was working quite right this weekend!

But I do agree with you in that a new trailer would be the easiest way to get a new furnace!

[RBolton]

Ron,

I appreciate your concern for safety. I have read several posts concerning the older furnaces and have had mine inspected and am comfortable with it. I don't know if it is the original, although it is certainly not very new. I do believe the thermostat to be original though.

I have installed a CO alarm (high) as well as a propane detector (low.)


Lew,

Thanks for the info on the thermostats. The piece of paper trick is a bit of a hassle and I have forgotten to use it in the past only to return to the trailer mid-day and find the furnace wasting battery and propane while no one is around. At $20-$30 for a new t-stat it would not take long to pay off.

Roger