Water heater mystery?

[Cavie]

Originally Posted by Spower

Is the black part in the picture the check valve??

Yes it is.

[Camper_bob]

Originally Posted by Spower

Is the black part in the picture the check valve??

That's definitely where the check valve belongs, and it looks like there should be one on the cold AND hot side?

But a quick Google search revealed no replacement WH check valves made of plastic. They're all made of brass...

Edit: A little closer look reveals several types and styles of plastic check valves. I didn't see anything quite like what you have. But perhaps that's why it failed on the hot side? Perhaps the plastic didn't hold up to the heat?

[Cavie]

Originally Posted by kevysinc

I would think the check valve should be on the cold water inlet to the tank

It usually is but with remote valves it's anybody's guess. probably on both lines.

[JimD]

See post 23 for a picture of the brass check valve I ordered for my unit from Amazon.

[Spower]

Ok another update.....I pulled the check valve (plastic part) it looks fine but I am going to pick up a brass one tomorrow and put it in.

Maybe the plastic one just isn't seating well? I don't know, guess we'll see when I put in a brass one tomorrow.

[JimD]

Hopefully the plastic one was just expanding and binding when hot and not allowing water through it like it should. It should allow full flow in one direction whether it is hot or cold.

You can do your happy dance when you finally find out that this low dollar part was the thorn in your side and you finally have solved the problem.

[10yearsbehind]

My opinion, there should not be a check valve at all, without an expansion tank downstream of the check valve. When water gets hot it expands and increases pressure. The water needs a place to go. It goes back to the supply side (cold side) but it does not heat the entire cold supply because incoming pressure is pushing against it. When a check valve is installed an expansion tank must be installed for the water to go. Otherwise, the relief valve will drip, typically.

I realize many models likely have a check valve but I don’t see a reason for it. Just like a home, no check on the water heater. Sometimes a closed loop is created such as a backflow prevention device on the water service or a booster pump on the water service (which requires a check valve so you don’t boost the entire town, a well has a check valve already and an expansion tank). Again, this requires an expansion tank on the cold side downstream of the check.

So I suggest to eliminate the check valve.

[10yearsbehind]

Come to think of it, the water pump and city supply have a check valve anyway, so I guess it doesn’t matter. But remove the check on the water heater and be done

[norty1]

I re-sealed mine and used pipe thread sealant instead of the teflon tape and I believe it helps it stay tight with all the vibration and heat changes.

[Spower]

Originally Posted by 10yearsbehind

Come to think of it, the water pump and city supply have a check valve anyway, so I guess it doesn’t matter. But remove the check on the water heater and be done

I have seen comments about just getting rid of it but some have said you need it for the bypass when winterizing

[10yearsbehind]

Originally Posted by Spower

I have seen comments about just getting rid of it but some have said you need it for the bypass when winterizing

That makes perfect sense. With no check the water heater would fill with antifreeze. I winterize with compressed air so that would not be an issue for me...

[Cavie]

Originally Posted by 10yearsbehind

Come to think of it, the water pump and city supply have a check valve anyway, so I guess it doesn’t matter. But remove the check on the water heater and be done

By pass systems with just one by pass valve valve requires a check valve in the cold water supply. that's what I have had in two trailers.

[10yearsbehind]

So the purpose of the bypass valve is so the wh does not fill with antifreeze while winterizing. The check valve on the hot side after the tank prevents antifreeze from entering the tank via back feed from the cold side.

A single handle faucet, or shower diverter, mixes hot and cold water. This allows both lines to be open at once and they are both connected via the cartridge. So if there is no check on the exit of the wh tank it is possible to backfeed the cold supply through the cartridge and fill the tank (while winterizing).

The bypass allows the antifreeze to fill both hot and cold supplies without filling the tank. The check valve on the exit pipe won’t allow to fill from backfeed.

Essentially, every camper is a closed loop due to the check on the water pump and city water supply. So I am surprised every relief valve is not dripping.

I was wrong, that wh check valve is needed if using antifreeze to winterize

[10yearsbehind]

Oh yeah, because of the bypass valve it would automatically fill the wh tank with antifreeze without a check valve (while winterizing). The bypass makes the entire water supply system one pipe loop.

I’ll be quiet now...

[Spower]

Originally Posted by 10yearsbehind

I’ll be quiet now...

Hahaha! I love all the out loud thinking and all the help! That's how I learn!

Thank you!

[RetiredOne]

Originally Posted by 10yearsbehind

Oh yeah, because of the bypass valve it would automatically fill the wh tank with antifreeze without a check valve (while winterizing). The bypass makes the entire water supply system one pipe loop.

...

I have the same model water heater as the OP, but instead of the main control panel like them, I have the standard bypass valves right behind the heater. I also don't have any check valves that I can see on the heater.

Spower, have you tried to follow the hot water line when it leaves the heater, to see where it goes, what connections are down stream, and if any other shut off valves might be hidden further downstream?

[Spower]

Originally Posted by RetiredOne

Spower, have you tried to follow the hot water line when it leaves the heater, to see where it goes, what connections are down stream, and if any other shut off valves might be hidden further downstream?

Yes I have...no shut off valves

[norty1]

If you have a utility panel location, all the valves are in that location. Different rigs have many different ways of doing the same thing.

[Spower]

YES!!!! Replaced the puney plastic check valve that seemed ok, with a new brass check valve. Fired up the water heater.....so far so good, I have full pressure!!!
Yahooooo!!!!

[Pop#1]

In my new camper it proved to be a crimp in the hot water line.