We just returned from our maiden camping trip in our recently aquired Breakaway. As I stated in another post, it went flawlessly except for one problem. When I started my hot water heater for the first time, I got plenty of VERY HOT water. But, I also got a leaking water tank? It is located under the kitchen counter behind the sink. Funny thing, I noticed it leaking by opening a compartment underneath and water was dripping into it. I was hooked up to water at the site. At first I thought it might be a leak in one of the water lines, since I now had constant water pressure into the coach. I did have a water regulator on the incoming water line. Then I looked under the sink and saw the hot water heater and all the water around it. My wife's cousin, who we were with, suggested running the hot water until the tank emptied and then shutting it off. He said that the tank would not refill until the heater was started again? This seemed to help. I noticed that the tank was not just wet around the base, but also the "insulation paper" that surrounds the heater was quite wet. Any thoughts or comments? It looks as if this would be a difficult item to change in the coach, as there is no easy way to R&R the hot water heater.

Bruce, Check your pop off valve on your water heater. for some strange reason there seems to be a lot of those just going bad with no warning. ( Thanks Gunner) I had that problem last year. it worked fine one day and the next time we used it VERY HOT water started comming out the overflow. Gunner nailed it right away.
Yours might be something different but i would start there.

Ditto ironsides. Been there, done that.

If it's your typical Atwood or Suburban heater, it could very well be the pop-off valve, as has already been pointed out.....but it may not be a defective valve - just a waterlogged tank.....

Because a changing water temp also changes water volume (hotter = more volume, the valve could be "bumping open" to handle the need for this increased volume. Water heaters are designed to have a small air pocket within the pressure chamber to absorb this expansion....Without air to compress, the water needs to escape, so it appears to leak.

Here's the drill:

1. Water heater OFF
2. Incoming water supply OFF
3. Closest coach hot water faucet - OPEN
4. PULL pressure relief valve handle OPEN

-Allow all water to drain-

5. Allow pressure relief valve to CLOSE
6. CLOSE hot water faucet in coach
7. Incoming water supply ON to reill tank.

This may or may not be the problem, but for a couple minutes work and zero cost, it's worth a try.

A reminder: If the heater (heating element) is electric FILL THE TANK BEFORE TURNING IT ON or sufer the droopy element result, which means no more electric heating action.

It could also be caused by a faulty thermostat.

I usually turn the propane off before the thermostat kicks in, but on my last trip, one time I didn't. The popoff valve opened - it opens not only for overpressure, but over temp as well.

Another clue is that the overtemp breaker for the electric element also was tripping.

Thanks to all for their help. I am going to check out the pop off valve as soon as I can figure out where it is (I am not the most mechanically inclined and my tank is buried under the counter behind my sink). I will also use Lee's suggestion and try that method to insure the tank has an air pocket. I will follow up shortly with my findings.
Thanks again!

The popoff valve should be located outside; open the door to the HW heater compartment, and it should be at the upper left.

Rusty,
Thanks for the info. on the location of the pop off valve. Now that I found it, it is not the problem unless it is leaking before it actually gets to the valve itself. So, now I must do some exploring to try to make sure it is not "waterlogged" as a possibility and check the water lines. If it is not one of those, a replacement will be in order. Funny thing, they riveted the control panel where the pop off valve is. I would think that is where you would have the best access to the water heater itself, unless the heater is too big to fit thru that opening. The only other way to get to it in our coach is to remove it from under/behind the sink......
Bruce

The popoff valve is threaded directly into the tank; if the valve isn't weeping but there's still a leak there, the collar may be cracked, but that's unlikely; there may be insufficient sealant also, which is an easy fix.

The shelf and fascia over the HW tank remove easily. The supply/discharge fittings are a bit dicey to reach, but removal (from the inside as you surmised) isn't too bad. However, before doing that, I'd turn on the burner to the tank and see if the popoff valve starts discharging before the burner shuts off. That nails it to the thermostat, which is about $21, including the OT piece. Very simple to replace.