Furnace Blows a Fuse 2x a week

[DHSDawg]

About every 3 days our furnace blows a fuse. There isn't anything else listed on that circuit. It's a 15 Amp fuse. We have to turn the thermostat off, replace the fuse and turn the thermostat back on. Nothing in the manual mentions this. Anyone else have this problem in a 2016 Sanibel?

[King Ranch 53]

Originally Posted by DHSDawg

About every 3 days our furnace blows a fuse. There isn't anything else listed on that circuit. It's a 15 Amp fuse. We have to turn the thermostat off, replace the fuse and turn the thermostat back on. Nothing in the manual mentions this. Anyone else have this problem in a 2016 Sanibel?

Look for anything obvious, like a loose wire on the blower motor or, if you can navigate a multimeter, look for shorts or grounds in the wiring. I have not had this problem with any of my rigs, but I am a heating contractor and will be glad to discuss this with you.

Good Luck!

[DHSDawg]

Thanks for the info.

[King Ranch 53]

You bet! Let me know if you need any help.

Good Luck!

[Skyliner]

If nothing is obvious with wiring such as a loose connection, exposed insulation that causes wire to short with vibration of blower motor, check the blower motor out. A bad motor and/or motor bearing may cause electrical load to momentarily exceed the fuse rating. Check to see it spins freely, if possible clean any link/dirt off of it, relube it, and try again.

If everything checks out, then I would do the following:

Install a 20 amp hour fuse. The additional 5 amp hour rating won't put your rig at risk of fire if a short occurs. Don't expect Chinese made fuses to actually perform as they should meaning a 15 amp fuse made in China may actually blow at a lower current flow.

If you are not comfortable with a 20 amp fuse, get a resettable 15 amp fuse. You can get one that is auto-reset or a manual reset one. These typically are slower acting and actually blow at the rated current.

[DHSDawg]

Thanks for the info. We'll check out the things all of you have mentioned.

[jtesta1]

First thing you need to do is check your voltage .furnaces are very sensitive to correct voltage.

[ben31]

Really, get some good US-made fuses. I'd start there. While you are replacing the fuse, be sure to look at the contacts, into which the fuse sits. If those are corroded at all, you might be getting some arcing in there (which will kill the fuse). Clean those up. THEN start troubleshooting elsewhere. Check the easy or most likely items first, and then move on to the harder items.

[5picker]

Originally Posted by Skyliner

If nothing is obvious with wiring such as a loose connection, exposed insulation that causes wire to short with vibration of blower motor, check the blower motor out. A bad motor and/or motor bearing may cause electrical load to momentarily exceed the fuse rating. Check to see it spins freely, if possible clean any link/dirt off of it, relube it, and try again.

If everything checks out, then I would do the following:

Install a 20 amp hour fuse. The additional 5 amp hour rating won't put your rig at risk of fire if a short occurs. Don't expect Chinese made fuses to actually perform as they should meaning a 15 amp fuse made in China may actually blow at a lower current flow.

If you are not comfortable with a 20 amp fuse, get a resettable 15 amp fuse. You can get one that is auto-reset or a manual reset one. These typically are slower acting and actually blow at the rated current.

This is excellent advice on all accounts.
Thanks to Skyliner for providing.

[DHSDawg]

I've gotten more practical advice today from fellow RVers than any website or manual. Thank you all for your help.

[5picker]

Originally Posted by DHSDawg

I've gotten more practical advice today from fellow RVers than any website or manual. Thank you all for your help.

I am absolutely convinced manual writers have never camped a day in their lives.

Mine appears to have been written as a third grade class assignment.

[DHSDawg]

😃.

[Jonol]

Does the fuse blow when the furnace just start?
If so, check the blower motor.
Does the furnace smell funny when it stop?

[DHSDawg]

Unfortunately the fuse blows in the middle of the night. We go to bed with the thermostat set to 65° and wake up freezing in the middle of the night. We turn the thermostat off, replace the fuse then turn it back on and it lasts another 2-3 days without a problem. We haven't ever noticed an odor.

[DHSDawg]

Originally Posted by jtesta1

First thing you need to do is check your voltage .furnaces are very sensitive to correct voltage.

Will do. Thanks.

[DHSDawg]

Originally Posted by ben31

Really, get some good US-made fuses. I'd start there. While you are replacing the fuse, be sure to look at the contacts, into which the fuse sits. If those are corroded at all, you might be getting some arcing in there (which will kill the fuse). Clean those up. THEN start troubleshooting elsewhere. Check the easy or most likely items first, and then move on to the harder items.

Thanks so much. We'll definitely check it out.

[TimVWulp]

Hi is the trailer plugged into a 110 volt power supply? The furnace is a power hog and will drain a battery down very fast if it is not being recharged by trailer battery charger. As the battery voltage drops the amps to run the furnace or any device on the battery power will increase. This is one of ohms laws. This may be a possible cause for the fuse blowing. The other possibility may be a + 12 wire that has rubbed and or cut through the wire insulation causing a short or path to ground. This may be an intermittent problem which may make it hard to find.

Be careful with up sizing the fuse from 15 to 20 amps! If the wire is smaller than 12 Gage wire it is not rated for 20 amp max. if it 14 Gage it is good for 15 amps max.

Is this a new trailer do you have a warranty? IF it is and you can't fix schedule an appointment date to have it repaired you control the time for the repair. The dealer will ask you to just drop it off and they will repair it. If you do it this way you may not see the trailer back for a while.

Hope this helps Tim

[DHSDawg]

It is a new fifth wheel under warranty. Our truck is in the shop right now so it will be a week or so until we can get it to the dealer. Last weekend we noticed fluid around the bottom of 3 of the jacks, so that's on the list too. Thanks for your help.