Problems with furnace breaker

[Retiredrvbud]

On a recent trip in our motor home which is a 99 winnebago chieftain we encountered a problem with our furnace. What was happening was every 10 minutes or so the breaker would pop and the furnace would shut off. After a couple of minutes we would reset the breaker and it would run again for another 10 minutes or so and pop again. Sometimes it would run a lot longer before the breaker would pop.
What could the cause of this be?

[Rook]

What "breaker" are you referring to? Furnace fan motors are usually powered fron your 12VDC power system and are powered from your house batteries/Inverter system. Rook

[David Kanoy]

Retiredrvbud,

I had similar issue, turned out to be defective (weak) 12 volt pop-out style fuse (breaker)
Replaced fuse/breaker, all good for years now.

Hope yours is that simple.

David

[George Schweikle]

Circuit breakers trip two ways; magnetically, and thermally. A magnetic trip is almost instantaneous and is caused by a very high load like a short circuit. A thermal trip is from a smaller overload that heats and bends a bimetal strip inside the breaker that eventually activates the trip mechanism. There are hold-in, trip-out curves required for breakers that mean that a breaker must hold for a certain time, depending on the overload, yet must also trip within a time. The smaller the overload, the longer time for the breaker to trip and vice-versa. It sounds like your breaker was just doing what it was designed to do since the bimetal was cooling during the time the breaker you waited to reset it. Was there another fairly large load on the same circuit?.

Having said everything above, it is not unknown for a breaker to loose calibration and not act like is is supposed to do. This can be nuisance tripping, or failure to trip when it is supposed to do. If you are comfortable doing this, find another breaker (of the same rating) in your panel and exchange this with the furnace breaker and see if it still trips.

Quote:

Originally Posted by Retiredrvbud On a recent trip in our motor home which is a 99 winnebago chieftain we encountered a problem with our furnace. What was happening was every 10 minutes or so the breaker would pop and the furnace would shut off. After a couple of minutes we would reset the breaker and it would run again for another 10 minutes or so and pop again. Sometimes it would run a lot longer before the breaker would pop. What could the cause of this be?

[Retiredrvbud]

Thanks for the feedback. I will try changing the breaker and see if it works. Certainly worth trying

[Retiredrvbud]

Rook. The furnace in my motorhome has a separate pop out fuse/breaker so I assume it is wired in to the electrical system as a whole. The popping out has been happening when we are running the furnace while hooked up to 50 amp service

[Chief]

Agree with George above. Easiest troubleshooting fix is to exchange breakers. If it continues to pop the breaker then the fan motor is probably drawing a little too much current and will require service. Maybe too much dirt/dust/lint in the fan or the motor itself may be getting old and weak.

[Retiredrvbud]

Just had motor home serviced in Albany Georgia for a problem with the generator. While there mentioned the problem with the furnace popping circuit breaker after running for a while. They did a detailed check and finally found the wire connnector to the circuit breaker was blackened which they think indicates a loose connection. They cut the bad end off and installed a new connector and now the furnace runs without popping the breaker. A minor fix for a major pain of a problem with the furnace. I guess we can never be sure what is causing an issue.
Thanks to everyone who offered opinions last November. I wanted to share the outcome as it might help someone else in the future.