Water heater

[oldtrojan66]

Hey, Kids! How's tricks?

Old fart here, again, with a stupid question (I know, the only stupid question is the one that doesn't get asked).
I have an 07 JAYCO 36RLTS with an Atwood duel fuel water heater. The problem is for the first three seconds, the water is hot, then, pretty much right away it goes to luke warm. If I were back in the day, working on a customers domestic 52 gal upright water electric water heater, I would diagnose the cold water inlet pipe that directs the water to the bottom of the tank had come off. Rust or some other reason being the culprit.

I don't know how the Atwood is configured inside, but is this a possibility in the RV type heater? Is there a fix, or do I replace?

Thanks for the help, in advance. Y'all have never let me down, yet?

[oldtrojan66]

Okey dokey!I will check when I get back to rig. Thanks, all. Happy Trails!

[Old-Biscuit]

old guy wrote:
could be the valve in the back is broken and not in the proper position

Exactly.......

Just because BYPASS Valve handle turns does NOT mean the internals actually change position

With water heated place hand on HOT outlet line close to WH.

Then have someone turn on HOT at a faucet.
HOT outlet should be hot but if it changes temperature then bypass valve is problem (should be able to feel flow thru bypass line also)


Otherwise...........outside shower is allowing mixing of hot/cold
BUT I really suspect WH BYPASS

[Hondavalk]

oldtrojan66 wrote:


The shower has two separate knobs for cold and hot. The problem shows up when only opening the hot faucet. Both outside shower knobs are closed. In fact, I have lost the key for the door, outside!

While your outside shower has separate knobs the shower head probably has a shut off valve on it. If your water valves are open and the shower head valve is closed you will get the bleed through. I would also guess the door key is a standard CH751.

[RJsfishin]

Starting w/ a cold heater, how long does the heater burn till it shuts off ?
If a "stat" is opening after burning only a few minutes, you will have hot water for only a few seconds.

[Dutch_12078]

oldtrojan66 wrote:
Yep, just did a little more checking. Found a diagram of the major parts. Looks like inlet and outlet are on opposite sides and not at all likely to come off. The faucets are all turned off and the by-pass valve is in the correct position. I will try with propane heating and see if that makes any difference. If what I suspect is true, the heat source won't matter.

Try turning the by-pass valve the other way. It wouldn't be the first time a diagram didn't quite reflect reality.

[old_guy]

could be the valve in the back is broken and not in the proper position

[oldtrojan66]

Well, Old Biscuit, normally I'd agree with anything you say, but in this case, I must respectively differ. I checked the by-pass valve. There is a diagram right above it, indicating the handle position for "winterise" and "normal". Can't be but one of two ways.

The shower has two separate knobs for cold and hot. The problem shows up when only opening the hot faucet. Both outside shower knobs are closed. In fact, I have lost the key for the door, outside!

What we gonna do, in a few minutes when the DW steps in the shower and gets three seconds of hot water? And the propane switch is on, but not electric? Or even worse, it's normal on propane and acts up only with electric?

Ok, here's the report from the Mrs., same problem with propane as heat source!

Someone else care to ring in? Old Biscuit, any other thought? I agree with you, by the way. I just can't figure out how it's happening. The diagram I saw was on an Atwood site. I don't really know how I'm gonna check the integrity of the cold water inlet.

[Old-Biscuit]

HOT water going luke warm is due to cold being mixed with the hot.
Only 2 ways for that to happen


Water heater BYPASS Valve NOT CLOSED (LEAKING THRU)..........otherwise it will flow into HOT line overcoming the check valve in hot out on WH tank

OR

SHOWER (outside one or inside one) only turned off with lever/button on handle vs hot/cold knobs closed.
Cold water will overcome hot inside shower faucet


And NO.....heat source will NOT make a difference.
Your 2007 Vintage uses the SAME set of t-stats for propane and electric....so same temp on either heat source
140*F/T-stat OPENS
180*F/ECO OPENS if t-stat fails (ECO---Energy Cut OFF/High Temp T-stat)

[oldtrojan66]

Yep, just did a little more checking. Found a diagram of the major parts. Looks like inlet and outlet are on opposite sides and not at all likely to come off. The faucets are all turned off and the by-pass valve is in the correct position. I will try with propane heating and see if that makes any difference. If what I suspect is true, the heat source won't matter.

[DutchmenSport]

The first and most obvious in an RV: If you have an outside shower, make sure both faucets are turned off. If it's off just at the sprayer, the hot and cold are mixing and coming out ... anything but hot. The same is true for your inside shower, sinks, and anywhere else where hot and cold comes together. Turn all knobs off.