Why Does My Suburban Water Heater (Model # SW6DE) Blow Fuses?

[Dirt Duff]

My 2015 LE1 has a Suburban water heater model # SW6DE.  It blows the 15amp fuse as soon as I flip the rocker switch inside the trailer.   What is wrong?

I have changed the fuse but it blows each time.

The fuse blows on DC (not connected to electrical outlet) and on AC (when connected to electrical outlet.) 

Note that the SeaLevel tank monitor is on the same circuit but does not blow the fuse when I use it to monitor tank levels.   The rocker switch on the water heater itself is in the "off" position when the fuse blows.   I pushed the large rubber reset button in to reset the water heater.  (Note - I really don't know what the small rocker switch on the water heater and the large rubber "reset" button do.)

 

  

Edited October 7 by Dirt Duff

[topgun2]

Here's what "AI" has to say about the blown fuses:

 

"Your Suburban water heater is blowing fuses due to electrical problems like a faulty heating element, a short circuit in the wiring, or a failing thermostat. You should first check the wiring for loose or damaged connections and test the heating element and thermostat with a multimeter to identify the source of the electrical overload or short circuit."

Since you state that the on/off switch located on the water heater itself is always in the off position, it is likely that a bad heating element is not the problem.  Therefore, I'd look at the wiring and then the thermostat first.

Bill

p.s.  there are a number of videos on YouTube on how to test the water heater - like THIS ONE

Edited October 7 by topgun2

[jd1923]

2 hours ago, Dirt Duff said:

My 2015 LE1 has a Suburban water heater model # SW6DE.  It blows the 15amp fuse as soon as I flip the rocker switch inside the trailer.   What is wrong?

I have changed the fuse but it blows each time.

The fuse blows on DC (not connected to electrical outlet) and on AC (when connected to electrical outlet.) 

Note that the SeaLevel tank monitor is on the same circuit but does not blow the fuse when I use it to monitor tank levels.   The rocker switch on the water heater itself is in the "off" position when the fuse blows.   I pushed the large rubber reset button in to reset the water heater.  (Note - I really don't know what the small rocker switch on the water heater and the large rubber "reset" button do.)

Sorry for your troubles, but you have provided a lot of good info here!

The DC 15A fuse provides power to the LP side of the Suburban HWH, the Direct Spark Ignition, etc. If it is consistently blowing the fuse, you have a dead short in the path between the switch and the HWH. You could pull the switch from under the pantry to see if anything is wrong (use a thin putty knife around the edges), but more likely on your 10-year-old LE1 is the 12V+ line is corroded on the HWH side since it is out towards the elements. I'm not sure of the wiring, but check the wire shown bottom left in your picture, where it connects the the ignitor above.

Also, walk through troubleshooting in your suburban manual. I've attached below a PDF of the 2016 OTT Owner's Manual. First, search (Ctrl-F) for keyword 'Suburban.' When I got to the Suburban section of the manual, I clicked on the first page of the section and then searched for the word 'reset' to learn what the reset buttons are for. It appears the reset is used for re-lighting the HWH (see pic below), it resets to go through the self-ignite steps again to restart. I'm not 100% on this, haven't needed to use it.

The ON/OFF rocker switch, also bottom-left, is for 120VAC operation only. We leave ours ON always and when we want to run on shore power, and sometimes inverted power, we turn the 120VAC functionality ON/OFF by closing or tripping the HWH breaker in the 120V breaker panel. Much easier to flip and breaker inside, than to open the exterior door to the HWH. Chris has this all down now for our Oliver. When dry-camping, she asks me to turn on the gas, so she can start the HWH on LP and switch the fridge to LP. She also knows when on shore power to run both appliances on 120VAC.

Last thought... Your HWH has a dead short on the DC to LP side. You should still be able to run hot water on 120VAC, either on shore power and if you have a decent LiFePO4 upgrade it can be run on inverter (we do this often when SOC >90%). Just turn that "ON/OFF rocker switch" to ON.

2016-OTT-Owners-Manual.pdf

Edited October 7 by jd1923