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

Dutch_12078
Explorer II
May 31, 2022
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.
schlep1967
Nomad
May 31, 2022
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.
AdvancedQs
Explorer
May 31, 2022
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.
BB_TX
Nomad
May 31, 2022
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.
AdvancedQs
Explorer
Jun 08, 2022
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.
AdvancedQs
Explorer
Jun 08, 2022
Also, the cold water is alternating between hot and cold!

I can feel the temperature change from cold to lukewarm cold to lukewarm. And this happens when the pump cycles. When you are using the cold water it is mostly cold and alternates to a little bit of warm.

When you are using the hot water, it is mostly warm, not the full heat you would normally feel, and cycles a little bit cold.

The bypass valve is working properly. It is set to just send water from the freshwater system through to the intake of the water heater. And that’s it.

The heck could cause the symptoms? Also, the flow rate is very low.
AdvancedQs
Explorer
Jun 08, 2022
My screen name is definitely accurate. Ha ha ha. Advanced question, no doubt
dougrainer
Nomad
Jun 08, 2022
1. The BEST way to determine water flow and pressure is to NOT have the Water Heater heat up the water. Then OPEN the outside Pop off Valve. See if you have pressure/volume as it should be. IF NOT, then the check valve on the cold water intake(if you have one) is clogged/bad. Replace it.
2. IF the Water when calling for HOT is pulsating/alternating between hot and cold, YOUR BYPASS IS NOT FUNCTIONING CORRECTLY. Unless in your pic that pex pipe between the Hot output and cold Input is still in place.
3. "Some" OEM's install 2 Check valves on Water Heaters. A COLD input check valve and a Hot output check valve. With your single valve system BOTH are required. I would replace BOTH and use Brass as already used.
4. Put the system back exactly as original with new check valves and the new valve you purchased and problem will be fixed. Doug
AdvancedQs
Explorer
Jun 08, 2022
OK, I can definitely safely say that number #2 is known.

That bypass valve is set and tested to be set only in a way that it passes straight through to the water heater right now.

Literally removed the valve from the system, tested it in all of its settings, tested it with compressed air to make sure that it only goes in the direction I want it to, and it was completely airtight for the bypass section of pex and completely open to the hot water heater side.
AdvancedQs
Explorer
Jun 08, 2022
I will check #1 when the tank cools down a little bit.

Because I just used a generic picture to show a hot water heater and bypass, I’m going to put in pictures of my real system right now.

Would appear that there is only one check valve. Just on the hot water side. It’s a straight pipe in on the cold water side. Is that my problem then?

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