Motorhome hot water heater help...

your outlet checkvalve is plugged up or stopped opening you need to replace it

Is this a check valve? This is what I have on the outgoing (top) of my hot water heater.

If you look at the images that my website mentions, you will see that the check valve seems to have about 1/2 inch of unthreaded smooth brass. Your fitting looks like an adapter only.

Perhaps you have inlet and outlet valves instead of a check valve. One way to check your system to see if it is hot water tank related is to put it on "winter" bypass. If that makes the hot water lines (without the hot from the tank) run properly, your problem is in the piping for the HWT without a doubt.

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StephJohn2010 wrote:
Is this a check valve? This is what I have on the outgoing (top) of my hot water heater.

No that is not a check valve.

But it is the source of your problem.
It is a 'mixing valve'. Combines cold water with VERY hot water to give you a constant temp hot water.

It is clogged up with sediment/scale

Sometimes you can clean them out......remove and soak in vinegar.

Otherwise.......replace. About $140 for an Atwood one.
Your water heater heats the water to about 160*F and the mixing valve is set for roughly 130*F output.

Old-Biscuit wrote:

StephJohn2010 wrote:
Is this a check valve? This is what I have on the outgoing (top) of my hot water heater.

No that is not a check valve.

But it is the source of your problem.
It is a 'mixing valve'. Combines cold water with VERY hot water to give you a constant temp hot water.

It is clogged up with sediment/scale

Sometimes you can clean them out......remove and soak in vinegar.

Otherwise.......replace. About $140 for an Atwood one.
Your water heater heats the water to about 160*F and the mixing valve is set for roughly 130*F output.

Thank You Old-Biscuit. I was searching and searching last night for a check valve that looked like mine and got nowhere. Now I know it is a mixing valve. Just called a local RV guy (only game in town apparently) and he wanted $220 for the part. I now know the part is $120 so that guy just lost my business. I don't mind them making a small percentage on the product, but near 100% markup is offensive. I'm going to try and do it myself. Thanks again :)

Had to replace mine earlier this summer. Bought the valve from Amazon, and it was a pretty quick swap-job with a pipe wrench. Might have been a bit challenging, though, if I hadn't had clearance to get to it. Don't recall exactly what I paid for it, but $120 or so seems about right. I agree that your RV guy's markup is more than a bit excessive...

So could you just plug the one line put in a check valve and use more cold water at the tap and save some time and money??

John Wayne wrote:
So could you just plug the one line put in a check valve and use more cold water at the tap and save some time and money??

One COULD do away with the mixing valve........

BUT you would need to install a check valve in hot out...better yet install a shut-off valve in hot outlet line.
AND change the t-stat.
The water heaters with mixing valves use a 160*F t-stat.
Normal t-stats are 140*F
Atwood does have an adjustable t-stat (110*-150*F)

The reason for the mixing valve......extended hot water.
Get an equivalent of 16 gallons out of a 10 gallon WH tank (or 9 out of a 6 gallon tank)