15 amp appliance fuse

[NCRV]

I have a new E Pro 19fbs, the second time using it I had the appliance fuse blow. After blowing about 4 fuses I found that if I switched the hot water heater from electric to gas the fuse would not blow. Does this sound logical? Is there a connection with the hot water heater on this circuit?

[CHICKDOE]

i'm not totally sure but something doesn't sound right.

fuses are typically used for 12 volt dc circuits. water heaters use 120 volt ac circuits, plus a small load of 12 volt dc to run the control board when on gas. i'm assuming your appliance circuit is 120 volt ac and it is protected by a circuit breaker, not a fuse. it is possible that the electric side of the water heater is wired into the appliance circuit but the water heater itself can be around 12 amps. that would leave nothing for the other appliances.

[Flybob]

The only thing different on the 12V side between gas and electric is the solenoid on the gas line. Check the solenoid to insure nothing is shorted.

[NCRV]

The hot water heater worked fine on gas. When the fuse would blow the refrigerator and co2/gas monitor would not work. I took it back to the dealership, I hope they can figure it out.

[Chuck_S]

"Appliance fuse?" Is this unique to this camper?

Fuse or circuit breaker? Water heater on electric runs thru a circuit breaker.

Pretty sure mine is 15a breaker and there is noting else on that circuit. (Different trailer than yours of course.)

-- Chuck

[NCRV]

Yes Sir, it is a 15 amp DC fuse

[Flybob]

Did you by any chance run it on 120VAC without water in it?

[NCRV]

No

[CHICKDOE]

A 15 amp dc (12 volt) fuse (180 watts) is not going to the rlectric side of the water heater. It might be labeled as ‘appliance’ but only to provide power to the control boards. It is not operating the appliances.

If your water heater is like most the 12 volt control board is not even used when you operate it via the 120 volt ac side. So when you say you turn off the electric side of the water heater and then the fuse does not. Low that seems incorrect.

What switch are you using to turn off the electric side of the water heater? The one o the water heater itself or the one inside the RV? I’m just wondering if you are actually turning the gas side of the water heater off. This might indicate a short in the 12 volt wiring going to the water heater or in the control board.

[NCRV]

I turned electric off on the control panel inside, when the fuse blows the refrigerator and co/gas monitor don’t work. When I switched the hot water heater to gas the fuse stopped blowing

[NCRV]

Could the switch on the control panel be a problem?

[CHICKDOE]

This one is beyond me. I’m not familiar with your unit so anything I say is only a guess. I am still having a problem understanding how a switch for the electric side of a water heater is affecting a 12 volt dc fuse.. The electric side should be 120 volt ac and shouldn’t have any effect on 12 volt dc fuses.

We are talking about a traditional water heater aren’t we? Not one of those on demand or instant heat water heaters.

[NCRV]

I’m puzzled also. Yes it’s a standard suburban 6 gallon gas electric water heater. I was wondering if 12v and 120v come together on the water heater control board?

[Chuck_S]

Since it's back at the dealer -- who will fix it -- please let us know what the problem was. No point in anyone guessing anything more for now.

-- Chuck

[Scrapper]

Originally Posted by NCRV

I’m puzzled also. Yes it’s a standard suburban 6 gallon gas electric water heater. I was wondering if 12v and 120v come together on the water heater control board?

The only place the 12VDC and the 120VAC come together is the two ECO/Hi-Limit Tstat resets on the face of the HW. Other than that the two are separate.

[NCRV]

Thanks for the info and pictures

[Bama Rambler]

I know that it's at the dealer and I'm sure they'll get it fixed, but the only thing that I can think of that would cause the issue you're seeing is if there's a short between the 120 volt wiring and the 12 volt wiring. I also believe that's the case because once you turn off the 120 volt power the fuse doesn't blow.

[Scrapper]

Originally Posted by Bama Rambler

I know that it's at the dealer and I'm sure they'll get it fixed, but the only thing that I can think of that would cause the issue you're seeing is if there's a short between the 120 volt wiring and the 12 volt wiring. I also believe that's the case because once you turn off the 120 volt power the fuse doesn't blow.

And the most likely place for this to happen is at the ECO/Hi-Limit resets, hence the included picture in post #15.

[Alde]

Same thing just happened to our neighbor. On the back side of the heater is a 12 to 120 relay switch. The coil was shorted from the factory. Mobil mechanic replaced the mini relay. All is well. Same thing was happening you described. Mechanic had to remove heater to access where relay was and reinstall

[5picker]

Originally Posted by Alde

Same thing just happened to our neighbor. On the back side of the heater is a 12 to 120 relay switch. The coil was shorted from the factory. Mobil mechanic replaced the mini relay. All is well. Same thing was happening you described. Mechanic had to remove heater to access where relay was and reinstall

^^This may just be the issue.

There's been lots of speculation but I've not seen the OP say what model water heater they have. If it is the SW6DEL, then the the switch the OP is speaking of INSIDE does operate a 12v coil to turn on the 120v element.

If they have a SW6DE then the switch inside is for LP only and would have nothing to do with the 120v side.

The 12v and the 120v reset switches under the rubber cover are in close proximity to each other but not connected in any way via circuitry.