Furnace problems

[Ronecar]

During the night my furnace stopped blowing warm air. It will come on but only cold air comes up of the registers. I do have gas because the stove works.

 

[Isaac-1]

Do you know the brand and model of furnace?  Most are either Atwood or Suburban

 

[Rene T]

During the night my furnace stopped blowing warm air. It will come on but only cold air comes up of the registers. I do have gas because the stove works.

You say it comes on do you mean it fired up?  Go outside and see if there is heat coming out of the exhaust tube.

 

[Gary RV_Wizard]

I think he means the fan blows (is "on") but it probably isn't igniting the burner to provide heat.  Need more details as to what happens when it first switches on, e.g. can the spark ignition be heard (three tries).

My article on Furnace Troubleshooting will help: http://www.rvforum.net/miscfiles/Furnace_Trouble-2.pdf

 

[John From Detroit]

If the batteries go low then teh fan does not blow as hard as it does with full batteries.

If the fan does not blow hard enough the sail switch won't sail and thus won't switch and the heat will not come on.

That is the MOST COMMON failure. now there are other things as well such as a bad sail switch. bad ontrol bord and several other issues.

 

[Howard R]

What John says ... have been there and done that.  Years ago overnight at a truck stop woke up middle of night with furnace blowing cold air.  As soon as we fired up the RV to leave heat came back on. (probably had to recycle on-off switch).  Coach batteries got too low to give enough fan speed. 

I would check for that as a first step.

Howard

 

[billwild]

Perhaps a thermocouple needs replacing. A cheap fix.


Bill

 

[John From Detroit]

Thermocouples almost (I STRESS THE WORD ALMOST) Never fail. COnnections faill. the chip on the control board that senses the thermocouple fails but two pieces of metal. different  but  bonded. What's to fail?????

That said. since on many RV DSI devices the thermocouple is also half the "Spark Plug" they can fail.

 

[billwild]

Almost,,,,,I had one fail in our house. Replaced it and Bobs your Uncle, it was back to normal.


Bill

 

[Rene T]

Where did the OP go?

 

[DearMissMermaid]

Hope he didn't freeze to death!

 

[Ernie n Tara]

Therocouples don't usually fail, but it doesn't take much corrosion to disrupt a signal measured in milliVolts. Cleaning the connection(s) will usually fix them.

Ernie