Possible bad check valve on hot water tank

[Raise]

Hey guys, you all have been extremely helpful in the past. I have become pretty handy with fixing whatever goes wrong with our camper, but i needed to ask you guys about this. I know plumbing pretty well, and a bad check valve is the only possible culprit that makes sense to me. I was dewinterizing our 32’ Crossroads Reserve TT yesterday, and all was going fine until this happened. Let me start by saying the hot water tank is bypassed and has been all winter. I had flushed the antifreeze with fresh water from the fresh water tank. The next step was to refill the tank and add bleach to sanitize the plumbing system. I flushed the bleach with no problem as well. Then I filled the tank again for one more rinse/flush to make sure all bleach was gone. Well, this time when i kicked on the water pump, it kept running. In my mind, im thinking where could this water be going?? Then i heard the hot water tank filling. I checked the valves again and it is still in bypass mode, as the cold entry is closed and the bypass is open. There is a brass check valve on the hot water exit from the tank. I removed the hose and tried to loosen it but it is TIGHT!!! I put a breaker bar and 1” socket and still couldnt make it budge. I was afraid to put any more force on it because brass and aluminum are soft metals and i didnt wana break anything. My first question is this: am i correct in identifying the check valve as the culprit? Second question: is there a way to unstick it while it is still installed? I know check valves normally have a ball and spring, but i dont know the exact internal makeup of this one. Third question: any advice on helping this check valve to break loose without cracking the valve or tank?

[Wrapped]

If your water heater is still bypassed no water can enter the check valve. When your done flushing you freshwater tank close the water heater bypass and open the water heater tank valves, fill water heater tank and turn on the water heater. If the check valve is bad hot water will migrate back into the cold water system and you will get warm water from your cold water system, if you get cold water the check valve is good.

[Raise]

Originally Posted by Wrapped

If your water heater is still bypassed no water can enter the check valve. When your done flushing you freshwater tank close the water heater bypass and open the water heater tank valves, fill water heater tank and turn on the water heater. If the check valve is bad hot water will migrate back into the cold water system and you will get warm water from your cold water system, if you get cold water the check valve is good.

It certainly can. On the vertical line where the bypass valve is, it tees off at the top and water can pump over to the hot water exit on the tank, and if the check valve is bad, it will pump water right into the tank. Please see picture below. This is the configuration as it sits now, and when i turn my water pump on, the hot water tank starts filling. I can hear it, and just to confirm, i went outside and pulled the drain plug and with the bedroom window open, i can hear it draining out.

[Raise]

Well guys, I confirmed the check valve was bad by removing the hot water line and plugging it. I ran the water pump and the tank did not fill at all. So this made me want to try to remove the check valve again. To avoid the risk of cracking the fitting or tank, I was planning on leaving the check valve alone, and plumbing a new check valve inline just past the elbow. But i only had a few inches of Pex line to work with, so without removing the tank, it was very tight quarters to work in to cut, crimp, etc. Anyway, i got my heat gun and warmed up the check valve/bung area for a few minutes and tried the breaker bar again. It broke loose without damaging anything. I now have a new check valve on order. Thanks as always for the help guys

[Old-Biscuit]

YES as you found out,,,that hot out check valve was bad
Now it could have been stuck open from crud,,,,,,,or even the o-ring had becomes dislodged

They are just a plastic plunger/spring/o-ring assembly held in place by a small plastic clip on end of plunger

Sometimes if you tighten slightly then they will break free when trying to remove

[Raise]

Originally Posted by Old-Biscuit

YES as you found out,,,that hot out check valve was bad
Now it could have been stuck open from crud,,,,,,,or even the o-ring had becomes dislodged

They are just a plastic plunger/spring/o-ring assembly held in place by a small plastic clip on end of plunger

Sometimes if you tighten slightly then they will break free when trying to remove

Yup, I actually did crank to the right at first, then to the left, but no movement. So i added some more heat and i finally heard the crack

[Raise]

Originally Posted by Old-Biscuit

YES as you found out,,,that hot out check valve was bad
Now it could have been stuck open from crud,,,,,,,or even the o-ring had becomes dislodged

They are just a plastic plunger/spring/o-ring assembly held in place by a small plastic clip on end of plunger

Sometimes if you tighten slightly then they will break free when trying to remove

I just ordered a replacement for now. But i think after the season is over i may just put a 90 elbow on the outlet and install an inline check valve just downstream from the elbow. That way if it fails again, i can just loosen clamps and replace instead of risking another seizure in the tank

[MFL]

Hey Raise, good to hear you got the old one out! Those are known to fail, and not an easy out, as you know. I saw your post earlier, but had a mission of my own going on, so just returned home.

Good luck, happy camping to you and family!

[Old-Biscuit]

Originally Posted by Raise

I just ordered a replacement for now. But i think after the season is over i may just put a 90 elbow on the outlet and install an inline check valve just downstream from the elbow. That way if it fails again, i can just loosen clamps and replace instead of risking another seizure in the tank

Install a shutoff valve instead of another check valve.

[MFL]

Lots of good advice from Old-Biscuit, including installing a shut off valve vrs CV.

[Raise]

Originally Posted by MFL

Hey Raise, good to hear you got the old one out! Those are known to fail, and not an easy out, as you know. I saw your post earlier, but had a mission of my own going on, so just returned home.

Good luck, happy camping to you and family!

Thanks a lot buddy, same to you

[Raise]

Originally Posted by Old-Biscuit

Install a shutoff valve instead of another check valve.

Ok, but then while camping, wouldnt you have to keep opening it and closing it the whole trip?

[Old-Biscuit]

Originally Posted by Raise

Ok, but then while camping, wouldnt you have to keep opening it and closing it the whole trip?

No need/reason to do that.
My 5th wheel had 3 valve setup---NO check valves
*check valves are installed by RV MFG (not water heater mfg) ---less labor involved, quicker & check valves installed prior to installing WH Tank

Normal operation
Open the cold inlet valve
Close the Bypass valve
Open the hot outlet valve

Bypass Operation
Close the cold inlet valve
Open the Bypass valve
Close the hot outlet valve


This shows one in Bypass Mode

[Wrapped]

Old biscuits picture is what a water heater bypass is supposed to look like, your missing a shut off valve on the hot water exit,that's why I said no water should be getting to your check valve. The purpose of the bypass setup is so when you winterize you don't waste 6 or 10 gallons of antifreeze filling the water heater tank. The check valve let's cold water enter the tank but doesn't let the hot water migrate back into the cold water system. Glad you got your problem fixed.