furnace fuse blowing

just a follow up for all the people that helped and if interested...

Most places wanted $100-120 just to hook it up to power and bench test it, then diagnostics, plus repairs/parts.

I wasn't willing to pay that on a unit that was over 20 years old and constantly giving me problems so I bought a new one for $460 on Amazon, installed it and all is good, it runs and cycles as it should. I'm happy, and warm...for now. :)

thanks again everyone!

I think it was near the end of last winter it stated blowing the fuses. Around the time I stated this thread.

no problem... when did it start blowing fuses (ie. history of events)? "bench test" will at least indicate if the "unit" versus external wiring is an issue... maybe.

budwich wrote:
I guess you "own the problem"... :-)
disconnect the power wires going to the furnace, plug in a new fuse, does it blow? No? then its not the wiring going to the unit. Yes, then its the wiring going to the unit. Since you are the one that has been "playing" in the unit, it is likely that "playing" may have introduced the problem, such as miswiring, shorted connection / chafed wiring. Further, disconnect all wiring going to the control board except the power leads (ie. 12v and ground), does the fuse blow? If not, then your issue is with the "stuff" coming into the board. If yes, then your problem is with the board.

One other thing, you refer to "the unit" but exactly what are you "playing with"... the control board, the motor, the thermostat? what wiring are you actually disconnecting / connecting?

I don't mean to be difficult here.

The unit as I refer to it is the furnace assembly, all I have done to it has been pull it out of the camper by disconnect the wiring and gas line. I have taken it to the dealer for repairs in the past, 2 years ago was the latest, a blower motor was replaced. That is spinning freely.

I have the furnace at home and wanted to put power to it with an inline fuse as a bench test.
good idea checking to see if the fuse blows with unit wires disconnected.

thanks,
Jim

I guess you "own the problem"... :-)
disconnect the power wires going to the furnace, plug in a new fuse, does it blow? No? then its not the wiring going to the unit. Yes, then its the wiring going to the unit. Since you are the one that has been "playing" in the unit, it is likely that "playing" may have introduced the problem, such as miswiring, shorted connection / chafed wiring. Further, disconnect all wiring going to the control board except the power leads (ie. 12v and ground), does the fuse blow? If not, then your issue is with the "stuff" coming into the board. If yes, then your problem is with the board.

One other thing, you refer to "the unit" but exactly what are you "playing with"... the control board, the motor, the thermostat? what wiring are you actually disconnecting / connecting?

budwich wrote:
that's why you need to do the checks that have been suggested to determine what the h.ll the problem is. IF you don't want to do that, replaced the unit, and see if that works. That's a "strategy" but probably not one most people would follow. Replacing the unit won't solve issues with wiring going to the unit... but I assume you will have someone do the work so it will become their problem (if it doesn't work), so you can go across that "bridge" if necessary.

No, I will replace the unit myself as I have pulled it out many times to have it in for repairs, I was just thinking if I do a bench test that it would blow the inline fuse telling me the issue is in the unit itself which I would replace. If it ran fine during the bench test I would assume the problem is in the wiring leading to the unit in the camper and not buy a new furnace.

I know I could check individual switches etc to pinpoint the issue but not interested in replacing parts on the furnace.

thanks.

Jim

time2roll wrote:

jimmypsp700 wrote:
So you think the fuse blowing problem can only be caused by the unit then?

Get a clamp-on ammeter and see what amps are going into the furnace unit.

thanks.
not familiar with that but will look into it.

Jim

jimmypsp700 wrote:
So you think the fuse blowing problem can only be caused by the unit then?

Get a clamp-on ammeter and see what amps are going into the furnace unit.

that's why you need to do the checks that have been suggested to determine what the h.ll the problem is. IF you don't want to do that, replaced the unit, and see if that works. That's a "strategy" but probably not one most people would follow. Replacing the unit won't solve issues with wiring going to the unit... but I assume you will have someone do the work so it will become their problem (if it doesn't work), so you can go across that "bridge" if necessary.

So you think the fuse blowing problem can only be caused by the unit then?