Check valve for gravity hot water re-circulation

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bhoth

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Ok I just removed the heat trap on both the hot and cold side in the second WH and the hot side on the first WH. It was a super easy job just grabbed it with a pair of needle nose pliers and it pulled right out.

Crossing my fingers this does the trick and I am done messing with this!:)
 

bhoth

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Well with the 3 heat traps removed as mentioned above, the hot water loop works better than ever until we turn on the shower. For some reason it still gets cold water added to the hot when the shower is on.

Now what?
 

Widgit Maker

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Widgit Maker

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Bend the piping so that the input side of the check valve is lower than the output side. Indications are that the flow of water up the re circulation line (when faucet is opened) is not enough to close the check valve. Let gravity help it close.
 

bhoth

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No.


You said the PVC check valve worked. Suggest you examine how it is made and how it works and compare it to how the the CPVC valve works.
The difference is the pvc check valve was a rubber hinged pvc flapper valve. The cpvc is a ball valve. I could start by setting the valve straight horizontal. To do that I would have to add another 90 degree ( so from behind the furnace I would come straight out then a 90 degree turn straight down to the water heater)
 

Reach4

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I would try moving the recirc line to the second heater rather than the first. My hope is that the recirculation flow would increase, so the water in the recirc line would be warmer.

The horizontal check valve seems to have some merit, or even maybe it should have a slight reverse tilt if that is what it takes to keep it open at low flow conditions, I would think.
 

bhoth

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I would try moving the recirc line to the second heater rather than the first. My hope is that the recirculation flow would increase, so the water in the recirc line would be warmer.

The horizontal check valve seems to have some merit, or even maybe it should have a slight reverse tilt if that is what it takes to keep it open at low flow conditions, I would think.
The flow on the loop itself is actually very good since I removed the 3 heat traps.
I have now modified the check valve with a 90 degree connection so the check valve is level. It was leaning downhill before. See pic below:
26643943550_5d872cab4a_o.jpg

That sounds like a vertical check valve. Does the ball float?
No it does not float, the ball is actually not a ball, think of it more as a cup, the flow side is rounded but the back side is cup shaped to grab water and push itself closed.
 
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Widgit Maker

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Well, is it working? If so great, if not keep raising the out put side until it does . Being made of plastic and light weight the gravity flow will probably push the cup open even if the inlet side is tilted down as much as 45 degrees.
 

Reach4

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Where does the described cold water come from? If the water is circulating, the return line water should at least be warm. The bottom of the WH with a circulation current, while cooler than the top, should still be fairly hot, right?
 

bhoth

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Well, is it working? If so great, if not keep raising the out put side until it does . Being made of plastic and light weight the gravity flow will probably push the cup open even if the inlet side is tilted down as much as 45 degrees.
The tell tale is the next morning when my wife gets in the shower. So I will know tomorrow morning.
 

bhoth

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Where does the described cold water come from? If the water is circulating, the return line water should at least be warm. The bottom of the WH with a circulation current, while cooler than the top, should still be fairly hot, right?
I am assuming the bottom of the WH because if I shut off the loop, the shower instantly jumps hotter!
 

bhoth

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Ok my wife says it's the same. So now I am moving the return loop from the bottom of the first WH to the second WH. Should I put back in the heat trap on the hot side of the first WH and the cold side of the second WH?

Thank you,
 

Reach4

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Ok my wife says it's the same. So now I am moving the return loop from the bottom of the first WH to the second WH. Should I put back in the heat trap on the hot side of the first WH and the cold side of the second WH?
I think it won't matter.

Can you measure the temperature of the return water line? Maybe an IR thermometer could measure, or you could lay a probe along the pipe and wrap around the probe and pipe with a towel. A meat thermometer or candy thermometer (that is not also a deep fryer thermometer) should have a good range. Maybe if you measured the temperature before and after the pipe move, that could judge the effectiveness of the move. I think that higher return temperature would indicate more effective.

If the horizontal pipe with the check valve has enough slack, it seems to me that you could tune the angle to what works best.
 
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Hey, wait a minute.

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