Gravity recirc loop strange problem

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Benze

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A ball valve is NOT a precise method, since you do NOT know when it is "1/8 open" and even then it would be more than the 1/8" hole. The hole is a "fall back method" which I never used. I just mentioned it as an alternative way to maintain flow. The small hole will create more than enough "resistance" so that the water has an easier path going the "right way" to the faucet, thus backflow would be negligible at best, or worst.

Thanks for the explanation. I added a picture to my above post indicating how I am set up around the HW tank. I had to replumb my pex a little to put the valve in at 45dev, but at least now I can put it level if really needed. Ideally, I would rather avoid drilling a hole in the flap and trying to find a way around that. Unfortunately, I found out that they don't have 22.5 elbows in 3/4CU, and the only way to accomplish that would be to use some flex copper and bend it to fit. Problem is that they only sold flex 3/4 in 60' lengths, which is enormously too long for me.

I'll try putting it "level" and rotate the whole the Tee at the bottom of the tank counter-clockwise slightly to give it a slight pitch and let you know how it works.

Tx,

Eric
 

Benze

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I'll try putting it "level" and rotate the whole the Tee at the bottom of the tank counter-clockwise slightly to give it a slight pitch and let you know how it works.

Ok - replumbed - again. This time put the check valve horizontal and rotated it a little (see picture). I put in a 2' level at the vertical to show the slope. The check valve allows water to flow from right to left (the arrow is on the back side with the tail on the right and the head on the left).

I ran some unscientific tests, but thought results should be the same. If I turn on the hot water faucet and close the valve on the return feed, a cup of hot water measures 130. If I open the return valve, the temp drops to about 120. So I think that indicates that I am still getting a little cold water seepage backflow. If I rotate the checkvalve assembly Tee clockwise so that the valve is actually past the vertical and pointing downwards (ie: no way for the flap not to be closed), I am still seeing the same results (ie: water temp 120ish). If I shut the return valve, temp jumps back to 130.

So does that imply that
a) I've got a bad check valve (although looks fine visually)
b) My overall install is incorrect (I have the return line connected to a tee under the faucet and run directly back to the tank)
c) This is expected behaviour

???

Am so confused.... Something I thought would be fairly straightforward seems to be getting more and more out of hand.

Any thoughts? Thanks so much!

Eric
 

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Arfeller

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quote; think I'll move it back up to the top now that you have reminded me :

Do not do that, unless you intend to add a pump to the system. Just connect your existing piping, with a tee and drain valve directly to the water heater's pipe.

Yeah, i did not say that correctly. I meant I'll add it back to the top of my list.... not the tank. This is what I meant...
 

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Benze

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Yeah, i did not say that correctly. I meant I'll add it back to the top of my list.... not the tank. This is what I meant...

Do you have a valve on your return line that you can shut and see what kind of temp differential you get with or without it at the faucet?

Thanks,
Eric
 

Arfeller

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I don't have a valve on the return line. I'm not sure how much the loop reduces the overall temperature but I do know the water is plenty hot. I have hot water at all the fixtures when I wake up in the morning.

The only thing i have noticed is that if i have the kitchen hot water on and the bathtub hot water on, the last faucet on the loop (bathroom vanity) will be slightly cooler. Basically if you have the hot water on 100% with no cold you can just barely keep your hand in the water. However, if the other faucets are not running then the water is too hot to hold your hand in. This has not caused any problems but was an observation.
 

Benze

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The only thing i have noticed is that if i have the kitchen hot water on and the bathtub hot water on, the last faucet on the loop (bathroom vanity) will be slightly cooler. Basically if you have the hot water on 100% with no cold you can just barely keep your hand in the water. However, if the other faucets are not running then the water is too hot to hold your hand in. This has not caused any problems but was an observation.

Thanks for the info. I'm not 100% clear on your statement though; please let me know if I understood you right. If you have just the bathroom hot (nothing else in the house) running, it is hotter than if you are running the bthrm and kitchen and bathtub. Essentially, 2 different hot water temps from the same faucet depending on number of other faucets turned on.

Is that accurate?

Tx,

ERic
 

Arfeller

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Yep, and the vanity is the last faucet on the circuit, so closest to the tie in shown in the picture. I'm guessing the high demand from all the other fixtures reduce the line pressure and allow for more back flow through the small ~1/8" hole in my check valve to the bathroom faucet.
 

Jon229

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Last time I researched this subject this thread wasn't here. It's been helpful to me.
I'm finally ready to install this type of system and have a question.

In all the discussions I've read the check valve is installed near the tank. I'd like to know if it would be more/less effective if it is installed near the distant fixture where the loop begins or if it does not matter where it is installed in the line as long as it is on the return side.

Thanks, Jon
 

hj

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Just remove the mechanism from the valve, screw a tee onto the nipple from the heater, screw the check valve into the end of the tee, then screw a hose faucet into the side of the tee.
 

Jon229

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Just remove the mechanism from the valve, screw a tee onto the nipple from the heater, screw the check valve into the end of the tee, then screw a hose faucet into the side of the tee.

So check valve closest to WH drain. Thanks, HJ.
Rgds, Jon
 
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