# Shower valve to return cold water?



## mjay (Feb 2, 2006)

I'd like to add a valve after mixer valve that will return water below a certain temperature to the tank. Thus avoiding wasting water and standing under a cold shower.
Many Thanks for any help advice.
Mike


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## Inner10 (Mar 12, 2009)

Put a re circulation pump on the line so you get instant hot water.


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## mjay (Feb 2, 2006)

Thanks
Was hoping for a simple valve, pump is overkill for my needs.


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## Golden view (Feb 16, 2012)

It won't work without a pump. The pressure on both sides of the valve will be equal so it won't flow.


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## KermieB (Jul 27, 2012)

mjay said:


> I'd like to add a valve after mixer valve that will return water below a certain temperature to the tank. Thus avoiding wasting water and standing under a cold shower.
> Many Thanks for any help advice.
> Mike


I have a question....


Why?


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## huggytree (Nov 3, 2013)

you dont need a pump....gravity will move the water if you have a seperate return line coming off the hot side of the shower piping...run it to the drain line at the bottom of the water heater....you can add a valve to the system to throttle it back(and save $$)...it will work so good you can most likely throttle it back 1/2 way.....ive even done this in the basement right under the shower when i couldnt open up the wall....even 8' of gravity was enough to make it work....the higher you can get the return line the better...try to pitch the pipe flat or pitched down/back to the water heater


another thing ive been using alot lately is the Grundfos comfort system...its an after the fact recirc system...it recirc's the hot through the cold water....the valve goes under any sink...it comes with a pump...it needs to push the hot...gravity wont work without a 3rd water pipe(return line)


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## Inner10 (Mar 12, 2009)

huggytree said:


> you dont need a pump....gravity will move the water if you have a seperate return line coming off the hot side of the shower piping...run it to the drain line at the bottom of the water heater....you can add a valve to the system to throttle it back(and save $$)...it will work so good you can most likely throttle it back 1/2 way.....ive even done this in the basement right under the shower when i couldnt open up the wall....even 8' of gravity was enough to make it work....the higher you can get the return line the better...try to pitch the pipe flat or pitched down/back to the water heater
> 
> another thing ive been using alot lately is the Grundfos comfort system...its an after the fact recirc system...it recirc's the hot through the cold water....the valve goes under any sink...it comes with a pump...it needs to push the hot...gravity wont work without a 3rd water pipe(return line)


How the hell does that work, wouldn't the pressure equalize almost immediately?


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## Dave in Pa (Oct 10, 2009)

I have a well for my water supply, and did it to not waste the pump! I put a return line, "AS" stated above, from the hot line, before the tub/shower valve, returning to the hot water tank. Put a check-valve in it, and remove the plastic crap on the bottom of the tank drain with a "t" to connect return line, with a shut of valve to regulate, with a new valve to drain the tank, and be happy forever! It might take a few to get it to work correct, but it will! My basement is cold in the winter, and to get it started to work, I had to flush the drain for a minute or two, then was fine!
Opps! how does it work? Help me out here if I am wrong, But I was told that HOT water is heavier than Cold??? I have not a clue nor good reason!! LOL It worked for me.


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## Inner10 (Mar 12, 2009)

Dave in Pa said:


> I have a well for my water supply, and did it to not waste the pump! I put a return line, "AS" stated above, from the hot line, before the tub/shower valve, returning to the hot water tank. Put a check-valve in it, and remove the plastic crap on the bottom of the tank drain with a "t" to connect return line, with a shut of valve to regulate, with a new valve to drain the tank, and be happy forever! It might take a few to get it to work correct, but it will! My basement is cold in the winter, and to get it started to work, I had to flush the drain for a minute or two, then was fine!
> Opps! how does it work? Help me out here if I am wrong, But I was told that HOT water is heavier than Cold??? I have not a clue nor good reason!! LOL It worked for me.


It's lighter, that's why in a hot water tank the hot water comes out the top. In a shower loop without a recirc pump I think you are just letting convection do the work.

But I'm still surprised it works worth a sh!t...unless you turn the valve, wait 20 minutes then have a shower.


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## TimelessQuality (Sep 23, 2007)

I have gravity recirculated hot in my home and it works well... Nearly instant hot water. 

An added bonus is the movement of water through the water heater extends the life.. I've got nearly 20 yrs on a standard 40 gallon gas unit.


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## Dave in Pa (Oct 10, 2009)

TimelessQuality, I have to agree with ya! Sure not knowing the years on mine, doing fine! Don't want to get the wamooie on it? And with the new boiler valve to drain it, NOT the plastic POS with a well, I need to do that!


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## superseal (Feb 4, 2009)

I wish somebody would explain the science behind this...it baffles me that it works so well, or apparently so anyway :blink:


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## pdmig (Nov 21, 2010)

I think it works like this.... Hot fluids rise. Hot air and hot water. If you have a hot water tank and a loop form the tank up to the shower and down to the tank, the water will naturally circulate though the pipe. The hot water in the tank rises to the top as the cold drops down the pipe to the bottom of the water tank.

The advantage is that there is instant hot water. It sounds like the circulation helps the hot water tank last longer. 

A disadvantage is that you are heating lots of extra water as it circulates through the pipes. This may be fine in the winter as the heat just goes into the house.


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## The Coastal Craftsman (Jun 29, 2009)

superseal said:


> i wish somebody would explain the science behind this...it baffles me that it works so well, or apparently so anyway :blink:


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## Tinstaafl (Jan 6, 2008)




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## Tinstaafl (Jan 6, 2008)

Curse you, Barri. :laughing:


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## The Coastal Craftsman (Jun 29, 2009)

What are the odds of that. There's so many sample pics if that on google lol


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