Furnace malfunctioning

turbojimmy wrote:

Rmack1 wrote:
They have run into this problem with the Suburban furnaces before. They said they have a weak control board made in China that have been known to fail after six months. They are bringing a DynaSoar fan 50+ to replace it.

It's a shame but the furnaces in stick and brick houses have the same issue of cheap circuit boards. The relays are **** and the welds are shoddy. The same Chinese manufacturer makes them for most of the big brand name furnaces. My 5-year-old Goodman furnace failed recently (fan relay on the circuit board). Gone are the days where major appliances last decades.

I hope that control board fixes it for you!

It did!

It was the control board sure enough. I wonder how much they save by buying p.o.s. Chinese boards.

Another strange thing; the tech could not remove the propane elbow after removing the whole unit to let it slide out. It was starting to distort with a heavy leverage. He said he's never seen anything like it, and he's done hundreds of them.

We finally had to cut the metal casing to slide the unit out to get to the board.

He checked the electric and I had plenty of juice. It was all the board.

Rmack1 wrote:
They have run into this problem with the Suburban furnaces before. They said they have a weak control board made in China that have been known to fail after six months. They are bringing a DynaSoar fan 50+ to replace it.

It's a shame but the furnaces in stick and brick houses have the same issue of cheap circuit boards. The relays are **** and the welds are shoddy. The same Chinese manufacturer makes them for most of the big brand name furnaces. My 5-year-old Goodman furnace failed recently (fan relay on the circuit board). Gone are the days where major appliances last decades.

I hope that control board fixes it for you!

Matt_Colie wrote:
Rmack1,

You may be on shore power, but you still need to check the house battery. There is a very good chance that the converter supplied with the unit is either failed or never was adequate to the task. Many light travel trailers are shipped with converter/chargers that will not manage this situation. Many of the furnace fans draw a lot of power and assuming that the house bank is OE, it is probably past its prime and cannot recover in the furnace cycle times.

Did you check that the battery water is at level? If it is not, that battery may well be toast by now, but topping it up is worth a try. Don't use campground tap water if you can get distilled or at least deionized.

I suggest that you get and carry even a cheapy of a meter to actually diagnose the situation. If you can't manage more, get a voltage readout that goes in a DC mousehole - lighter socket thing.

So, you have some choices right now.
=> If it used to work and now does not, replacing the battery may get you by. No Promise.
=> If it never worked, go get a good converter that can support the electric load of the heating system all by itself. This will be a good long term fix.
=> Get and electric blanket and leave the heat off until you are about to get out of bed.

Matt

I have a small electric heater that I forgot to bring with us.

I had two new bad-ass 6 volts installed before this trip, and they performed very well when we dry camped for a few days a couple of weeks ago.

I'm in Mt Shasta, CA, and I'm having a tech come out tomorrow to look at it. They suspect the control board. They have run into this problem with the Suburban furnaces before. They said they have a weak control board made in China that have been known to fail after six months. They are bringing a DynaSoar fan 50+ to replace it.

Rmack1 wrote:
Well, I installed a new thermostat, but it still doesn't work. It clicks when I move it back and forth, but no fan, no heat.

Bummer. Can you hear clicking at the furnace? Or just the thermostat itself? If you hear clicking at the furnace, then:

- Make sure you have adequate voltage to the furnace. Like someone else said, that's a 12V furnace. Being plugged in doesn't guarantee you have adequate voltage to it
- Make sure the fan spins freely
- See if you can get the fan to start by spinning it by hand first

If all of the above checks out and it still doesn't work, I'd suspect a bad control board (specifically the fan relay on it).

The fan starting is the very first in the sequence of events that will ultimately lead to heat. No fan = no fire = no heat.

Rmack1,

You may be on shore power, but you still need to check the house battery. There is a very good chance that the converter supplied with the unit is either failed or never was adequate to the task. Many light travel trailers are shipped with converter/chargers that will not manage this situation. Many of the furnace fans draw a lot of power and assuming that the house bank is OE, it is probably past its prime and cannot recover in the furnace cycle times.

Did you check that the battery water is at level? If it is not, that battery may well be toast by now, but topping it up is worth a try. Don't use campground tap water if you can get distilled or at least deionized.

I suggest that you get and carry even a cheapy of a meter to actually diagnose the situation. If you can't manage more, get a voltage readout that goes in a DC mousehole - lighter socket thing.

So, you have some choices right now.
=> If it used to work and now does not, replacing the battery may get you by. No Promise.
=> If it never worked, go get a good converter that can support the electric load of the heating system all by itself. This will be a good long term fix.
=> Get and electric blanket and leave the heat off until you are about to get out of bed.

Matt

ksg5000 wrote:
Furnace fan is a battery eater - when batteries get depleted the fan slows down and eventually the sail switch closes which shut down the furnace. Common for furnaces to shut down in the middle of the night when batteries are iffy. Check your batteries. If your connected to shore power then this likely doesn't apply.

Rmack1 wrote:
Yeah, I'm in an RV park with full hook-ups

Then use a couple of electric heaters instead of the stove to keep warm until you sort this out ... much better option than being dead from CO poisoning. :R

turbojimmy wrote:
If moving the thermostat back and forth allows it to work again, then it's probably the thermostat. I had to replace both of mine last season. They did the same thing - audible click at the furnace but nothing else. Furnaces would work fine for a while, but then not fire up for seemingly no reason (usually in the middle of the night). I haven't had any issues since replacing the thermostats.

Well, I installed a new thermostat, but it still doesn't work. It clicks when I move it back and forth, but no fan, no heat.

If moving the thermostat back and forth allows it to work again, then it's probably the thermostat. I had to replace both of mine last season. They did the same thing - audible click at the furnace but nothing else. Furnaces would work fine for a while, but then not fire up for seemingly no reason (usually in the middle of the night). I haven't had any issues since replacing the thermostats.

ksg5000 wrote:
Furnace fan is a battery eater - when batteries get depleted the fan slows down and eventually the sail switch closes which shut down the furnace. Common for furnaces to shut down in the middle of the night when batteries are iffy. Check your batteries. If your connected to shore power then this likely doesn't apply.

Yeah, I'm in an RV park with full hook-ups