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]

dougrainer wrote:

boshog wrote:

dougrainer wrote:
2 things I doubt you have checked. Doug
1. PULL the black OFF/ON switch below the gas valve. Make sure it is NOT corroded/burnt and the wire connections(spade terminals). This is a common problem and fits your problem.
2. The wire nuts where the 120 romex connects to the water heater. IF they were loose and burnt, you will have your type problem. This connection is where that relay is, you may have to pull the heater to check it. Make sure you have NO 120 power when pulling the black switch.

Oh boy. Well, I'm going to have to put on a miner's hat and figure out how to get access to the back of the on/off switch and find the AC connection point to the water heater. Wish me luck. If you don't hear from me in a few days, call search and rescue 🙂

The switch pops out from the outside. It has fingers that hold it in place. Doug

The switch checks out OK, the spade terminals are clean. Also pulled the thermostat and check for dirt/corrosion, none. Both thermostats holding hardware tight.

It is going to take me a while to figure out how to get behind the water heater and find the AC connection.

[dougrainer]

boshog wrote:

dougrainer wrote:
2 things I doubt you have checked. Doug
1. PULL the black OFF/ON switch below the gas valve. Make sure it is NOT corroded/burnt and the wire connections(spade terminals). This is a common problem and fits your problem.
2. The wire nuts where the 120 romex connects to the water heater. IF they were loose and burnt, you will have your type problem. This connection is where that relay is, you may have to pull the heater to check it. Make sure you have NO 120 power when pulling the black switch.

Oh boy. Well, I'm going to have to put on a miner's hat and figure out how to get access to the back of the on/off switch and find the AC connection point to the water heater. Wish me luck. If you don't hear from me in a few days, call search and rescue 🙂

The switch pops out from the outside. It has fingers that hold it in place. Doug

[boshog]

dougrainer wrote:
2 things I doubt you have checked. Doug
1. PULL the black OFF/ON switch below the gas valve. Make sure it is NOT corroded/burnt and the wire connections(spade terminals). This is a common problem and fits your problem.
2. The wire nuts where the 120 romex connects to the water heater. IF they were loose and burnt, you will have your type problem. This connection is where that relay is, you may have to pull the heater to check it. Make sure you have NO 120 power when pulling the black switch.

Oh boy. Well, I'm going to have to put on a miner's hat and figure out how to get access to the back of the on/off switch and find the AC connection point to the water heater. Wish me luck. If you don't hear from me in a few days, call search and rescue 🙂

[dougrainer]

2 things I doubt you have checked. Doug
1. PULL the black OFF/ON switch below the gas valve. Make sure it is NOT corroded/burnt and the wire connections(spade terminals). This is a common problem and fits your problem.
2. The wire nuts where the 120 romex connects to the water heater. IF they were loose and burnt, you will have your type problem. This connection is where that relay is, you may have to pull the heater to check it. Make sure you have NO 120 power when pulling the black switch.

[boshog]

dougrainer wrote:

boshog wrote:
Well, this is frustrating. Saturday morning, Out in the rain I go to sample the RV's hot water temperature. It's piping hot!

I'm going to assume you folks don't think I'm nuts. Now it is working but last camping season it was consistent, initial heating cycle only on electric.

Looking over all the information I've been provided there are two areas of possibilities, the thermostat which I assume turns on the heating element when the water temperature drops below a preset threshold value or the possibility of the on/off switch (I did cycle the switch). The relay shown in the schematic that feeds the on/off switch I can not locate.

Did you check the mount nuts for the tstat like I asked? Doug

The relay is mounted inside a metal box accessed usually by pulling the water heater. Unless they have inside access. Facing the water heater from the outside, the relay mount is to the LEFT top about 4 inches from the outside access door.

Yes, checked everything, fasteners and wire connections. Reconnected all wiring points which likely wasn't too smart since the issue is gone and I don't know why.

I'm going to put the inspection covers back on and see what happens. Right now I don't have an explanation why this happened. If anything happens I'll post back but for now, thanks everyone for your inputs.

[boshog]

DownTheAvenue wrote:
I am not trying to dilute your thread, but I wish you would consider the if you have an outside shower to check that. It is not about leaks. It is about turning the shower off at the shower head but leaving the valves open. This causes the hot water to mix with the cold and produce lukewarm water. It is possible for it not to do it all the time, as it did with me once. I know I anguished over the issue until I discovered the problem. You would be very wise to check that.

It is not the cause of my issue but thank you for your input.

[dougrainer]

boshog wrote:
Well, this is frustrating. Saturday morning, Out in the rain I go to sample the RV's hot water temperature. It's piping hot!

I'm going to assume you folks don't think I'm nuts. Now it is working but last camping season it was consistent, initial heating cycle only on electric.

Looking over all the information I've been provided there are two areas of possibilities, the thermostat which I assume turns on the heating element when the water temperature drops below a preset threshold value or the possibility of the on/off switch (I did cycle the switch). The relay shown in the schematic that feeds the on/off switch I can not locate.

Did you check the mount nuts for the tstat like I asked? Doug

The relay is mounted inside a metal box accessed usually by pulling the water heater. Unless they have inside access. Facing the water heater from the outside, the relay mount is to the LEFT top about 4 inches from the outside access door.

[DownTheAvenue]

I am not trying to dilute your thread, but I wish you would consider the if you have an outside shower to check that. It is not about leaks. It is about turning the shower off at the shower head but leaving the valves open. This causes the hot water to mix with the cold and produce lukewarm water. It is possible for it not to do it all the time, as it did with me once. I know I anguished over the issue until I discovered the problem. You would be very wise to check that.

[boshog]

j-d wrote:
^^^ I agree this thread is getting hard to follow. So at the risk of redundancy:

Have you verified that the 120 VAC supply to the water heater is solid? I went through a lot of trouble and a couple OP's here suggested the problem could be in a junction/splice box.

It is possible but very unlikely because the issue is (was) repeatable and has an exact behavior. On electric heating, it heats the water the first time but does cycle heat after the initial heating (electric only, propane works as expected).

Now that it is working I have to wonder what I disturbed when I pulled the inspection covers from the thermostats and the heating element.

I hate problems like this, if something is going to break, then break and stay broken so I can find you and replace you 🙂

I'm going to pull the A/C thermostat and see if there is any corrosion/dirt between the sensor and the tank that could be causing an issue.

[j-d]

^^^ I agree this thread is getting hard to follow. So at the risk of redundancy:

Have you verified that the 120 VAC supply to the water heater is solid? I went through a lot of trouble and a couple OP's here suggested the problem could be in a junction/splice box.

In our case, the water heater power connection box has a short lead of ROMEX cable to a junction box right behind the heater. In other words, less than a 3-foot run.

I opened that splice box up and found the the white neutral line had burned its connection out. I didn't replace the box, rather I gutted it and made the connections with wire nuts. The fix turned out to be very easy, but I'd wasted a lot of time checking Element, Thermostat, Two Switches, on and on.

If you have a connection feeding the water heater, that's gone intermittent, it could be causing your sometimes yes/sometimes no, heating issue on electric.

BTW - It's GOOD that Jayco installed the water heater with that short run and then a junction box. There is NO reaching the actual connections on the water heater unless the heater is removed or the cabinet is dismantled.

[boshog]

DownTheAvenue wrote:

Old-Biscuit wrote:

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

The OP only said that on propane, it cycles as expected. That does not necessarily mean that the water is constantly hot on propane but the burner cycles as water is drawn from the water heater. The outside shower is certainly something that should be checked. Always resolve and/or eliminate the simple things first.

Please stop polluting my thread with this, there are no water leaks or open faucets. If you read my OP that would be clear.

I'm really trying to troubleshoot an issue, not have a theoretical debate, I've narrowed it down to the items I've discussed. Thank you.

[DownTheAvenue]

Old-Biscuit wrote:

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

The OP only said that on propane, it cycles as expected. That does not necessarily mean that the water is constantly hot on propane but the burner cycles as water is drawn from the water heater. The outside shower is certainly something that should be checked. Always resolve and/or eliminate the simple things first.

[boshog]

Well, this is frustrating. Saturday morning, Out in the rain I go to sample the RV's hot water temperature. It's piping hot!

I'm going to assume you folks don't think I'm nuts. Now it is working but last camping season it was consistent, initial heating cycle only on electric.

Looking over all the information I've been provided there are two areas of possibilities, the thermostat which I assume turns on the heating element when the water temperature drops below a preset threshold value or the possibility of the on/off switch (I did cycle the switch). The relay shown in the schematic that feeds the on/off switch I can not locate.

[dougrainer]

The BLACK wires are the 120 tstat/eco. The red wires are the LP tstat/ECO. That center nut holds the tstats tight against the tank. With NO 120 power to the RV make sure both nuts are tight. IF they are not tight against the tank it will not sense the temp correctly. Doug