Furnace problems

[Lone Ranger]

Own 2009 3150RL Montana. Furnace fires for four seconds then shuts off, fires for four seconds then shuts off, etc, etc. Basically no heat. Isn't 2 years a little soon for furnace problems? Does anyone have some ideas for what's wrong???

[richfaa]

For starters switch over your propane tanks.

[Ozz]

Could be bad, or most likely dirty ground rod, sounds like it to me. Also a sail switch can cut gas off, but if it's the sail switch, it would not light to begin with.
You can clean the ground rod with a scotch-brite pad. Can also be loose wires, preventing a good signal from a clean ground rod. Get to it, clean it, just make it shiny.
Now, I have never worked on mine, (3400RL-'07) but a residential furnace has the ground rod, I have cleaned and changed out probably 300 of them. Sounds like the same problem/solution. Worth a try.
Good luck. Ozz

[snfexpress]

There are just a few basic parts to these blasted furnaces.

First, there is the circuit board, which is the easiest to replace. Typically, if the fan is blowing and WON'T turn off unless you either pull the 12v fuse or turn off the unit on top (there is a switch), then it is probably the circuit board.

Second, there is a sail switch. This is a switch inside the fan housing (4 screws to get the fan housing front half off). This switch has a long piece of metal on it about 1/4" wide. As the fan turns, the air pushes against this long thin metal strip and pushes it closed, which activates the switch. The switch is now allowing 12v to go thru it which in turn allows the gas valve to be able to operate.

Third is the electrode. This is a bear to replace (I did it, and it took me an hour to get the old one out and the new one in by wiggling it every which way in a very cramped space). The electrode, if bad, won't "spark" and ignite the gas. If you go to the trouble of getting the unit all the way out and on a bench, then I would take the extra time and replace the electrode. Oh, and you need to have the exhaust tube in place on the bench (or in the rig) when testing or the furnace won't light.

Fourth is the gas valve. I haven't replaced this valve, and if it every gets to that point, I'm just going to order a new furnace. Looks too complicated and dangerous, at least to me.

So, in order of price, it goes 1, 4, 3, 2. Roughly $170 for the board and just a few bucks for the sail switch and electrode. Don't know the price of the gas valve.

In order of difficulty, it goes 1, 2, 3, 4.

In order of your problem, I would suggest #3. Let me ask you: Does you furnace ever light? The unit will try 3 times, then "lock out", so you have to turn the unit switch off then back on. When you turn it back on (with the t-stat turned to furnace and calling for heat - set to 99 degrees), the fan should come on, then the ignitor on the circuit board (after about 20 seconds) should go click, click, click and then the propane should be burning. If the propane does not ignite, the exhaust sound will not change, and then the board will try a second and a third time.

Oh, I would try one thing first. Open your stove hood and disconnect the gas to the burners. Fit a gas gauge on to the propane supply line. It should read 11 inches Water Column (WIC) or about 3 lbs of pressure. But, Atwood's manual states that before doing a pressure check, to first disconnect the propane supply and cap this supply line to the furnace. If the pressure is low, go to your regulator and adjust as necessary (under the black cap on the regulator).

Sorry for the long post, and hope that what I wrote makes sense to you. Good Luck!

[Drifty1]

I have had a problem with the igniter on my 3295RK. But I also have had a problem with not getting propane to the furnace. The problem was caused by opening the valve on the propane bottle to fast and that would cause the float valve to stop the flow of propane to the furnace. This is a couple of items to check.

[Dui]

Had this problem last week and got this done under warranty. Dealer replaced the pigtails from the regulator to the tanks and it fixed the problem. Apparently there is a check valve in these pigtails that may become stuck and not allow flow on high demand.