A new furnace problem

[rickandjoyce]

I checked most posts/threads but didn't find a question like this. Any input would be appreciated.

We have been on a three month trip and mainly used our A/C. Then the weather abruptly changed and we needed to use the heater. It worked fine while we were just sitting around at night, but when we turned it down at night to a setting of 64 - it did not come on. We had to re-set it for it to come on.

Also, the noise from the furnace is not steady. It makes a kind of "rev-up" noise and then settles in and it goes back and forth doing that the whole time it is on.

We did hit a lot of bumpy roads and I don't know if that would have impacted it.

ANy help would be appreciated.

Joyce and Rick

 

[danemayer]

Hi Joyce and Rick,

Check the furnace vents outside to make sure nothing's built a nest and no leaves or other junk is blocking them. Also make sure your inside vents and air return are unrestricted.

 

[GOTTOYS]

Sounds like you might be running out of propane..Don

 

[rickandjoyce]

Thanks, but we checked that and we had plenty of propane. It's an enigma.

- - - Updated - - -

Thank you we did that and all looks clear so we shall see what happens tonight.

 

[JanAndBill]

Just went through diagnosis of a problem with ours. They can be a bit daunting till you learn how they operate. You didn't say what brand furnace it is?

 

[Wellis]

I may be having similar issues with my heat. I get what seams to be like a secondary firing. Outside at the exhaust the lower vent pops while the upper stays constant. Full propane and clear exhaust vents. Answers, suggestions?

 

[Dean-Pam]

A friend of mine with SOB had a similar problem the OP described. He took it into an independent RV service center and was told it was low pressure from regulator and it was a minor adjustment to increase the pressure. I don't know all the details, but he hasn't had any problems since.

 

[Wellis]

I'll check into that. That would be similar to the low tank example.Thank you for the info.

Sent from my SM-N920V using Tapatalk

 

[JanAndBill]

I may be having similar issues with my heat. I get what seams to be like a secondary firing. Outside at the exhaust the lower vent pops while the upper stays constant. Full propane and clear exhaust vents.

When the thermostat calls for heat it sends a voltage signal to the control board at the furnace. The board activates the blower. When it detects a signal from the sail switch that there is air moving through the combustion chamber, the board will activate the gas valve and the igniter. There is another sensor that tells the board if there is ignition. If ignition is not detected, gas is turned off, and the process starts over. The board will attempt to light the furnace three times before it will go onto reset mode. Finding your problem means starting at the control board and going down. You should be able to access the control board by removing the exterior panel. Carefully remove the board and take it to a dealer that has a tester. If he verifies the board as being good, then you'll likely need to pull the furnace to diagnose the problem.