Water heater will not remain ON.

[peggwn]

On our last trip, when we fired up the water Heater (Atwood 6-gal gas/elec. combo) all seemed well for about 10 minutes and then the pressure release valve popped and began spewing hot water. I had been meaning to replace it because when filling the WH tank after its last cleaning I had opened it to release air so I could be sure of a full WH tank, but then I had to actually push it back in (closed); it did not "snap" back into place. I surmised that the valve had finally failed. We used the CG showers for a couple of days. So, yesterday I replaced the pressure relief valve. While I was at it I also replaced the ECO and thermostat just in case they might have also contributed to the problem.

Well, I now have a new problem. I turned on the propane heating and it fired right up and ran for about 4-5 minutes, and then it shut down. I waited a while and tried again. Same result after a few minutes. I turned off the propane side. Next I decided to try the electric heating side. It came on (and drew appropriate amps) and after a few minutes, same result - it shut off. I get no hot water at any faucet.

I know the inside and outside shower valves are closed. One other possibility is the back flow preventer (check valve) on the back of the WH tank. I truly hope that isn't the problem because there is no access panel and I can only see it with an extension, flex-head hand-mirror; and I don't think I can get far enough inside the bay to use a wrench.

Well, there's what I know. I hope it's something simple and "dumb" on my part. I would never tell the DW that last comment. Thanks, guys and gals.

[LarrytheBear]

The first place I would check is the new thermostat that you installed. New parts are always suspect...

That's all I've got...

[Old-Biscuit]

When you state........

"I get no hot water at any faucet"

Do you mean......NO water flows out OR do you mean water flows but is NOT hot?


2000 vintage.......
Electric has its own set of t-stats. On backside of water heater in area where electric element is installed. They are 120V AC type....normal t-stat and an ECO (Energy Cut Off---High temp t-stat)
Propane has its own set of t-stats. In outside compartment Brown wire to t-stat, Red wire to ECO. 12V DC type.

If no flow..then YES check valve in HOT out (top fitting) is clogged and will have to be removed/replaced

If you get flow....but is warm then check if bypass valve got cracked open by mistake

Bypass closed....get flow but not hot
Then POP the NEW T&P Relief Valve and see if water is HOT

Only a few items STOP main flame (or energizing of element)
Water has reached normal t-stat temp setting (140*F)
Normal t-stat has failed and water overheats.....ECO opens shutting down heating/locks out---Fault light ON (180*F)

Propane only.....
Flame proving fails.
Circuit board doesn't get/keep Flame Lite signal...drops DC to gas valve shutting down heating/lock out---Fault light

So water flows and not hot
OR
NO water flows

??????????????

[peggwn]

Old-Biscuit, the water runs but is not hot.

[Old-Biscuit]

Originally Posted by peggwn

Old-Biscuit, the water runs but is not hot.

Have you POPPED open the T&P Relief Valve and checked IF water in WH TANK is HOT???


Propane uses one set of t-stats
Electric uses another set of t-stats

Each system is completely separate of each other.


Possible but doubtful that BOTH system t-stats are shutting down early

If water that comes out of T&P is cold/luke warm then bypass propane t-stat (outside compartment....brown wires) and fire off propane.

If propane stays ON for 15 minutes then propane t-stat is suspect.
But that doesn't account for electric shutting down early????


One step at time..is water in WH TANK HOT??

[peggwn]

To Old-Biscuit - I now have a flame that does not cut off until the water is hot. I replaced an extension wire to the T-Stat from the in-line circuit breaker (that elbow shaped wire enclosed in clear vinyl tube). I then check for continuity and it was now good. I also check the ECO for continuity; it wag good. Once the heater turned off I opened the T&P relief valve and the water is hot. I struggled but was able to squeeze into the bay far enough to put my hand on the hot water outlet at the back of the heater; it was cool to the touch.

So now my fear is that the back-flow prevention valve at the hot water outlet on the tank is blocked. I've watched several how-to videos and the process itself seems simple enough. However, they all show trailers or coaches that have have inside the coach access under a sink or through a removable panel. For our coach, there is no access panel so it's the access to that valve that will be a problem. If you or anyone knows of an easier way to get at that valve besides removing the entire heater I'd be very mush appreciative. Thanks.