Water heater help

[boshog]

In my two-year-old fiver (Montana 3790RD) I have a Suburban electric/propane water heater that is acting up. So my questions are, at this point, what to troubleshoot. I have not yet look at the water heater so this is going to be from the get-go.

The condition it is showing is, when I get to a campsite and after I make all my shore connections I turn on the water heater for electric heating. In an hour or so I have hot water, so far so good. In the morning, the water is luke-warm. The water heater initially heated the water but it does not keep the water hot over time on electric. I can switch on water heating by propane and the water heater cycles as one would expect.

The only thing I’ve check so far is to be sure I don’t have air pockets in the hot water flow. This issue is repeatable removing the possibilities of any resettable switches tripped. It has the marking of a faulty sensor that doesn't trigger the electric heating element once the water temperature cools below a threshold value.

Suggestions on what to look for? I really appreciate any help so thank you.

[boshog]

The weather cooperated and I have the RV's water system ready for use. I fired up the water heater on electric and right now, the water is nice and hot. I check the voltage at the heater element and right now it is off as expected.

In the morning I will check and see if the water is hot or luke-warm. I think I found the thermostat sensors. Are these them? If so, how do they work?

[Shot-N-Az]

I have experienced similar behavior and discovered that the exterior on/off switch was defective. I've replaced it twice now.

[Old-Biscuit]

Tom1949 wrote:

Old-Biscuit wrote:

Tom1949 wrote:
I know that this may sound oddball; but, it's helped others.

Check the outside shower head and make sure it is not in the "closed" position with the faucet left in the "on" position. It may be diverting enough hot water to effect your shower inside.

OP gets hot from electric 1st heat cycle then NO more heating and gets hot from propane with repeated heating cycles.

Issue is with electric side of WH.


Shower ----luke warm regardless of heating method

OP stated, "The condition it is showing is, when I get to a campsite and after I make all my shore connections I turn on the water heater for electric heating. In an hour or so I have hot water, so far so good. In the morning, the water is luke-warm."

My suggestion could still apply. I've seen it apply, in exactly that manner. The idea is there, if (s)he wants to try it; and, it certainly doesn't hurt me if (s)he doesn't want to try it.

Have a wonderful day...

You didn't finish OPs statement

The water heater initially heated the water but it does not keep the water hot over time on electric. I can switch on water heating by propane and the water heater cycles as one would expect.


Shower being turned off at handle has caused luke warm conditions. All the time not just with one heat source.
OP electric heating intermittent and OK using propane.

Shower idea is a good one to check..in situations where luke warm water is all the time.

Information/learning/discussions are GOOD things

Have a wonderful day too :B

[Tom1949]

Old-Biscuit wrote:

Tom1949 wrote:
I know that this may sound oddball; but, it's helped others.

Check the outside shower head and make sure it is not in the "closed" position with the faucet left in the "on" position. It may be diverting enough hot water to effect your shower inside.

OP gets hot from electric 1st heat cycle then NO more heating and gets hot from propane with repeated heating cycles.

Issue is with electric side of WH.


Shower ----luke warm regardless of heating method

OP stated, "The condition it is showing is, when I get to a campsite and after I make all my shore connections I turn on the water heater for electric heating. In an hour or so I have hot water, so far so good. In the morning, the water is luke-warm."

My suggestion could still apply. I've seen it apply, in exactly that manner. The idea is there, if (s)he wants to try it; and, it certainly doesn't hurt me if (s)he doesn't want to try it.

Have a wonderful day...

[dougrainer]

I would suspect the 120 tsat/ECO is NOT tight on the inner tank. Check the nut that secures it to the tank.
As to the DEL relay. ALL that relay does is the same thing the Atwood relay does. It just closes the current to the 120 side of the water heater. Since it is 12 volt activated, I doubt it would intermittently malfunction. Once closed, the Suburban operates on 120 like the other models. Doug

[Old-Biscuit]

Tom1949 wrote:
I know that this may sound oddball; but, it's helped others.

Check the outside shower head and make sure it is not in the "closed" position with the faucet left in the "on" position. It may be diverting enough hot water to effect your shower inside.

OP gets hot from electric 1st heat cycle then NO more heating and gets hot from propane with repeated heating cycles.

Issue is with electric side of WH.


Shower ----luke warm regardless of heating method

[Tom1949]

I know that this may sound oddball; but, it's helped others.

Check the outside shower head and make sure it is not in the "closed" position with the faucet left in the "on" position. It may be diverting enough hot water to effect your shower inside.

[Chris_Bryant]

Ah- never mind- I figured it out- do'hh.

[Old-Biscuit]

boshog wrote:
Wow, you know your stuff. Thanks. I'll be getting into this weekend if the weather holds (SE Michigan) and I'll post up what I find.

I know about Atwood Models....pre 2003 and post 2003
I know about Suburban standard models

The DEL Model....just learned about it last month thanks from an RV.NET member who posts on here as 'ktmrfs'
I had only come across the DEL model ('L' being the odd identifier) on a few occasions but never had to troubleshoot one

So when 'ktmrfs' brought it to my attention I had to investigate and learn about them.

Thanks 'ktmrfs'!!

[boshog]

Wow, you know your stuff. Thanks. I'll be getting into this weekend if the weather holds (SE Michigan) and I'll post up what I find.

[Old-Biscuit]

boshog wrote:
The model number of the water heater is SW12DEL.

You have the odd man out model for Suburban

Electric on/off switch on panel inside rv is a 12V DC switch that goes to a DC Relay that 'triggers' the 120V AC the OEM on/off switch in outside compartment then to the set of t-stats then to element.

So could be loose connections on:
DC Relay
Outside On/Off switch
Set of t-stats
Electric element

[boshog]

The model number of the water heater is SW12DEL.

[Chris_Bryant]

I would replace the electric thermostat.

[Old-Biscuit]

Electric element is under cover below/behind gas valve.
Check for loose wiring on terminals....black & white
Elements either work or don't work unless wiring/connections are loose


Suburban water heater has SEPARATE sets of t-stats for electric and propane.
Each set controls their own heating cycles

Electric uses a 120V AC set......normal/130*F (controlling t-stat) & high/170*F (backup/shuts down heating----needs to be manually reset)

Propane uses a 12V DC set......Same set up as electric

They are under the rubber cover above gas valve with 'Push to Reset'
So that the hi t-stat can be reset if it trips

Left side/electric
Right side/propane

If the electric hi t-stat was tripping YOU would have to manually reset it before electric would work again

Sounds more like normal has loose connections or not being held tight against tank wall
Open the 120V AC circuit breaker for WH electric element (or on/off switch OFF----but I don't trust them)
remove rubber cover and check wire terminal/spade connectors and if t-stat mounting is tight

Or buy new set and just replace it


NOW if you have a DEL model then electric uses a 12V DC relay to trigger electric element so that is another item to check on electric heating side.....ONLY ON DEL model

[jorge3000]

Could it be a weak/short in the circuit or possible weak heating element? Those would probably be my first 2 items to check.