A few months back my hot water heater bypass valve blew apart. Luckily I was in the RV when it happened so I caught it. Otherwise my entire water tank would have ended up on the floor in the RV. The body of the valve blew apart. This is under normal 12v pump pressure. So I ordered a replacement Flair-It valve off Amazon. This exact one: https://www.amazon.com/gp/aw/d/B002UCAE2U?psc=1&ref=ppx_pop_mob_b_asin_titleIt had 2 settings. Flow through or divert. It didn’t let the hot water fill up on the flow through setting and I guess diverted fine. So then I ordered this one. It has 3 settings. Pass through, divert and combine. https://www.amazon.com/gp/aw/d/B00IRUNEIA?psc=1&ref=ppx_pop_mob_b_asin_titleOne setting turns off my hot water entirely. The other 2 settings make it so I can feel some warm water coming through, but as the pressure of the line drops waiting for the pump pressure switch to engage, it goes cold. I’m at my wits end here. I can’t see why these simple replacement valves aren’t working. Any ideas? I’ve wasted $30 or so on this now. Getting so frustrated that it doesn’t work, but I’m just thinking of taking out the bypass entirely.

You only need the first valve to set up the winter bypass system. There's a check valve at the hot water outlet that prevents water from back feeding into the heater tank when the bypass is active. I don't know what you were trying to accomplish with the second valve.

You do not want Combine as an option on that valve.First, turn off the water heater and your water pump or city supply.Then remove the plug or anode rod and drain the water from the tank.Set the valve where you think no water should be going into the tank. Turn on the water and go see if water is coming out of the water heater. If no water coming from the tank turn on a hot water spigot inside. If you get water out of it, the valve is where you need it for winterizing. Mark it and turn off the water.Now you have two options left for operating position. Pick one of those 2. Turn the water back on. Are you getting water out of the tank drain? If no, go to position 3. Are you getting water from the tank drain now? If you only get water in one of the two positions, that is your normal operating setting.If you get water from the tank drain in both of the positions, you will have to fill the water heater, heat it back up and see which one gives you hot water and which on might give you warm water.

schlep1967 wrote:You do not want Combine as an option on that valve.First, turn off the water heater and your water pump or city supply.Then remove the plug or anode rod and drain the water from the tank.Set the valve where you think no water should be going into the tank. Turn on the water and go see if water is coming out of the water heater. If no water coming from the tank turn on a hot water spigot inside. If you get water out of it, the valve is where you need it for winterizing. Mark it and turn off the water.Now you have two options left for operating position. Pick one of those 2. Turn the water back on. Are you getting water out of the tank drain? If no, go to position 3. Are you getting water from the tank drain now? If you only get water in one of the two positions, that is your normal operating setting.If you get water from the tank drain in both of the positions, you will have to fill the water heater, heat it back up and see which one gives you hot water and which on might give you warm water.OK. This is pretty good advice. Thank you. Just stepping back and doing it a little more logically. I figured I could just throw in a valve, especially the two a one that I had got initially, and it would just work as it always has.I guess there is some testing I should be doing instead. Good point.And yes. That combine option is just superfluous. I just wanted to get some other fitting that may work. Since the two way fitting did not work. Which didn’t make any sense to me.

You could do what you were trying to do with two of the first valve. Two 1/4 turn 3 way valves is a common simple arrangement for a water heater bypass. Provides a secure bypass in the event of a leaking check valve due to mineral deposits or other crud.

OK, now it’s getting really tricky. It had nothing to do with that valve. I am passing straight through that valve now. Straight through from the freshwater system to the hot water heater without bypass. All I did was take the valve off and confirm what setting causes it to just go straight through to the hot water heater. Just to be careful, I replaced the valve again in case I got a defective one. So it is definitely not allowing anything to go through the bypass and everything is going to the hot water heater yet I still have a lot of problems.There is only a trickle of water making it out of the hot water heater.There’s nothing else involved here except the check valve on the hot water heater. Is that what’s wrong? Is that what blew up my bypass valve originally? Because it blew up when I turned the hot water heater on.This is how much water I’m getting out at full open tap. On the hot water side. Just a trickle. And it’s kind of warm. But it gets kind of cold here and there also.If it’s the check valve I’m going to be a little upset because this hot water heater is like a year old. It was working great. And now all of a sudden it’s not.

Plumbing Confusion | Good Sam Community

dougrainer
Nomad
Jun 08, 2022
Thanks, this helps.
1.The top(hot output) is the check valve. The bottom is not a check valve
2. If you did NOT have the check valve on the Hot, in your system, when in bypass mode, the cold water would go UP that center pipe and then flow into the Water Heater from the top. As it is designed, when in bypass, it shuts water OFF to the cold input at bottom, then goes UP that center connecting pipe and when stopped by the check valve will then run cold thru the hot water pipes. So, NO water goes into the Heater tank.
3. I WOULD suggest replacing the Brass check valve. They get mineral deposits and sometimes the "valve" itself gets cockeyed and restricts normal flow.
4. Replace the check valve and I think your problem is solved. Doug
Bobbo
Explorer II
Jun 09, 2022
When I de-winterized my Airstream this spring, I was getting little water from the hot water tap. I took a wooden rod and gently tapped on the backflow check valve at the top of my water heater, and the hot water stream increased significantly. I think either that valve had stuck, or some detritus had partially clogged it up. When I tapped it it either unstuck, or the detritus flushed on out.
schlep1967
Nomad
Jun 09, 2022
As said above, with the pump on, open the pressure release valve. You should get a lot of water coming out. Leave it open for a few seconds to ensure the flow continues. If you do not have good flow there, I would assume part of the broken valve may be in the section between the new valve and the tank blocking water flow. Easy to check by unscrewing fittings and looking. After draining the tank of course.

If you have good flow out the pressure release valve I would unscrew the plumbing from the hot out and check out the check valve.

As for the mixing of hot/cold water, you may have another issue going on. Check your shower to make sure the valves are closed (valves may be open with the button on the shower head turned off). Both the inside shower and the outside "shower". If these valves are left open it allows the mixing of hot and cold.
AdvancedQs
Explorer
Jun 11, 2022
Thanks, Doug and everyone.

I have normal flow out they release on the hot water heater outside the RV.

So yeah. It’s the check valve doing something weird. The new one will arrive tomorrow and I’ll update the thread with some results once I get that in.
AdvancedQs
Explorer
Jun 19, 2022
THREAD RESOLUTION:

It was the check valve on the hot water heater. Now all of the water is coming out at a normal rate, and there is no more weird mixing of hot and cold.

How exactly the check valve did that is still a mystery to me. But I did come out in pieces when I took it off.

Forum Discussion

Plumbing Confusion

About Technical Issues

Related Content

Towing tire confusion

Plumbing Management

Lithium Confusion

Puzzling Plumbing Problem

domicile confused