Can't Turn Off the Water Heater

[bmzero]

In my new-to-me 2008 Allegro Bus 40QRP, I have a traditional gas/electric 10G water heater in the rear of the coach. The two (gas and electric) control switches are above the driver's seat.

When I first got the the coach home, I plugged it in, added about a half tank of fresh water, and bled the lines. Then, I went to turn on the electric element in the tank (while plugged in to 50A plug at home). The switch did not illuminate, so I assumed it was not working. The gas switch was already in the off position.

I assumed it was a fuse and went on to the next inspection task. Oddly enough, I checked the hot water a little while later and it was hot and the gas switch was still in the off position. The electric switch had remained in the on position, but still with no light.

At that point, I assumed the light on the electric switch was not working since it was clearly heating the water. At that point, I turned off the electric switch since there was no need for hot water.

Oddly enough, last night, I heard the gas kick on in the hot water heater. I went and checked and the both switches were still off. Then, I went outside and flipped the on/off switch (to off) on the hot water heater itself.

How is the hot water heater still heating when both switches are off. I have looked for another switch, but have not found one. Could there be two switches?

[dabrooks]

I don't believe there are any lights that light on your hot water heater to indicate it is on. The rocker switches need to be pushed so the "O" is pushed down. The red light comes on if there is a problem with the gas side.

[bmzero]

Originally Posted by dabrooks

I don't believe there are any lights that light on your hot water heater to indicate it is on. The rocker switches need to be pushed so the "O" is pushed down. The red light comes on if there is a problem with the gas side.

Thanks for the reply.

There is a DSI round LED light for the gas switch. It does not illuminate, which is a good thing. However, the gas switch does illuminate when it is turned on, but that seems to have no affect on whether the gas part of the water heater is actually on or not.

The AC switch is the same style switch, so I assumed it would illuminate in the on position. I'm not really concerned about the switch illuminating, but I am concerned about not being able to turn off the water heater from inside the coach.

[billdreamlv]

Originally Posted by bmzero

Thanks for the reply.

There is a DSI round LED light for the gas switch. It does not illuminate, which is a good thing. However, the gas switch does illuminate when it is turned on, but that seems to have no affect on whether the gas part of the water heater is actually on or not.

The AC switch is the same style switch, so I assumed it would illuminate in the on position. I'm not really concerned about the switch illuminating, but I am concerned about not being able to turn off the water heater from inside the coach.

I just so happened to have our motorhome in the driveway and I went out to check how ours worked. I turned on the gas and threw the gas switch. The Switch lit up and the DSI lit as well. The DSI light cycled on and off several times and then seemed to timeout but the light DSI light stayed on. I shut the gas switch off and tried again. It cycled again 3 times and then I heard the gas lite and start to burn. At that point the DSI light went off and stayed off. Then I turned the gas switch off and heard the gas stop burning. I then turned on the electrical switch on and it lit up. I assume it was heating with electric. I did replace the switch (these do go bad) when I purchased the MH because it was not lighting up on the electrical side. That is what I know. You could have a relay stuck and that is what is keeping the unit on. Doesn't seem right, though. I would think the switch is bad as my first suspect. I went to an RV store and picked one up that looked like the one I had. Give that a try.

[billdreamlv]

Let me add that when the DSI light was cycling, I did hear a distinctive click. If you don't hear it is probably stuck. This is the valve that shuts your gas off when your pilot light isn't lit. You might check your regulator. And smell for gas.

[bmzero]

I spent some more time diagnosing this issue today. It has been driving me nuts.

After verifying DC power was making it to the panel mounted rocker switch, I then followed it back to the AC element on the HWH (intentionally went directly to the element bypassing the solenoid). No juice at the elemet. Odd.

Then, I looked up the wiring diagram for the switch, just on a hunch. It turns out the switch was connected incorrectly.

The only thing that makes sense to me is that at some point, the previous owner must have realized the rocker switch was no longer lighting up when the switch was on, so they removed it to check it. When they put it back, they did not connect the wires properly.

After wiring the switch correctly, it still did not light up, but the electric element did come on. Success!

Ordered a new rocker switch. All is well.

[billdreamlv]

Originally Posted by bmzero

I spent some more time diagnosing this issue today. It has been driving me nuts.

After verifying DC power was making it to the panel mounted rocker switch, I then followed it back to the AC element on the HWH (intentionally went directly to the element bypassing the solenoid). No juice at the elemet. Odd.

Then, I looked up the wiring diagram for the switch, just on a hunch. It turns out the switch was connected incorrectly.

The only thing that makes sense to me is that at some point, the previous owner must have realized the rocker switch was no longer lighting up when the switch was on, so they removed it to check it. When they put it back, they did not connect the wires properly.

After wiring the switch correctly, it still did not light up, but the electric element did come on. Success!

Ordered a new rocker switch. All is well.

Thank you much for posting the resolution. So many times some of us spend hours posting information about what we know to help others in their quest for help, and then nothing.

Yes, as I remember the switch, there are 3 poles to the switch and two of them are jumpered inside the switch in order to pick up the 12v for the light in the switch. It could have been that when they hooked up the switch incorrectly, it jumpered the 12v to the hot side of the heater, keeping it on perpetually. Glad you fixed it.

[bmzero]

Originally Posted by billdreamlv

Thank you much for posting the resolution. So many times some of us spend hours posting information about what we know to help others in their quest for help, and then nothing.

Yes, as I remember the switch, there are 3 poles to the switch and two of them are jumpered inside the switch in order to pick up the 12v for the light in the switch. It could have been that when they hooked up the switch incorrectly, it jumpered the 12v to the hot side of the heater, keeping it on perpetually. Glad you fixed it.

It's all about the community here on the forums. I'm a big fan of sharing knowledge, useful or not.

As for the switch, it was actually the gas that stayed on, not electric. I still haven't figured that on out, as the gas turns on and off fine now. May have just been an not often used switch or contact somewhere in the loop. I know it was the gas, because I heard it kick on n the middle of the night. The HWH is right next to the master bed. I'm not too worried about it now, since I can't reproduce the problem.

The new switch should be here today and I can put this behind me. That was the only odd thing with this coach, over the whole vehicle. We absolutely love the 40QRP.