My kitchen sink faucet and cold water heater:D couldn't be further apart without one of them being outside, so I am thinking about installing a recirculator pump system with a return line back to the cold water heater, to keep the hot water at the kitchen faucet when needed. I've read a lot about all the different types available and I don't like the idea of running the heated water back into the cold supply, so I want to do the return.

Because of the distance that would be needed to run the return line, I was thinking about using the copper tubing that is all one piece (50') and coiled in a box... much less sweating to do, but it would be much easier to use the 1/4" than the 1/2" tubing.

Would the 1/4" tubing be too restrictive for the system?

Seems like all it would really do is increase the amount of time it would take the pump to get the hot water to the faucet, but who cares? That would all happen when everything else is idle.

Some inputs on this would really be appreciated.

Thanks... Randy

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Originally Posted by icandoit

My kitchen sink faucet and cold water heater:D couldn't be further apart without one of them being outside, so I am thinking about installing a recirculator pump system with a return line back to the cold water heater, to keep the hot water at the kitchen faucet when needed. I've read a lot about all the different types available and I don't like the idea of running the heated water back into the cold supply, so I want to do the return.

Because of the distance that would be needed to run the return line, I was thinking about using the copper tubing that is all one piece (50') and coiled in a box...much less sweating to do, but it would be much easier to use the 1/4" than the 1/2" tubing.

Would the 1/4" tubing be too restrictive for the system?

Seems like all it would really do is increase the amount of time it would take the pump to get the hot water to the faucet, but who cares? That would all happen when everything else is idle.

Some inputs on this would really be appreciated.

Thanks...Randy

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Hey Randy, Welcome back.
You're a busy little bee, plumbing wise, aren't you?
It works like this. You tee off from the hot water supply in your sink and run the return line back to a circulating pump located in one of two places. The cold water supply on the heater or you tee into the drain at the base of the heater. There are no other options. Returning the cool water from the sink and then putting it into the hot water supply for the rest of the systen just cools down the temperature in the rest of the system and makes no sense.
You ask, "Would the 1/4" tubing be too restrictive for the system?
Seems like all it would really do is increase the amount of time it would take the pump to get the hot water to the faucet, but who cares?"

But isn't that what you're trying to get away from? The long wait for hot water to the sink? What you're overlooking here is volume. So you make a draw in your sink and you get hot water from the 1/4" recirculating line but bear in mind you also have a 1/2" branch filled with cool water supplying the faucet as well. If you run out of volume in the 1/4" line then the 1/2" branch takes over with cool water. When this happens you will have a draw of hot water that turns cool when the volume runs out. Also the pump is set up for a 1/2" line. To choke it down to half that size will build up back pressure on the pump making it work harder and wear out faster. Hope this answers your questions. Tom

Going to half as big of tubing will reduce flow or increase the back pressure by a factor of 16. However, the back pressure of the 1/2'' might be almost nil, so 16 times as much might not make much difference. At the worst, I would think that after standing with no use for a time, the hot water delivered in the kitchen might not be quite as hot. That would not be a problem for uses such as washing hands where you will be mixing in cold anyway. Even if you run the dishwasher without using any hot water before hand, the initial fill being not fully hot water will still be much better than room temperature water you have now.

I understand your problem. My hot water heater is in the front corner of the garage, with most of our hot water usage being in the back, middle of the house. I get sick of waiting for the hot or washing with cold. The tankless hot water heaters advertise instant hot water, but that would only be so if you could relocate the heater close to where you use the water. Likely I will end up adding a small electric waster heater near the downstairs powder room. That should be more economical than the recalculating system. It wouldn't work very well for supplying the kitchen. I hope you have looked at the operating costs of the system. Of course you are already wasting the hot water you run down the sink while you wait for it to get hot. Slowing the return, should reduce the cost of operating the system somewhat.

I agree with returning the cooled water to the hot water system. I avoid drinking or using for cooking, water that has stood heated in the tank and pipes. I don't even give it to the dogs to drink.

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You're a busy little bee, plumbing wise, aren't you?

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Yup... I am remodeling our entire basement, and so, have most of the walls and some of the ceiling ripped out. I figure this would be the time to do any and all upgrades I want while I have access.

My house is pretty much just a long box, with the main living area upstairs, and the garage underneath the front half. The other half is basement that was finished by previous owners, years ago. The kitchen plumbing is directly above one of the garage doors, so access to the plumbing there is easy. The water heater is a straight shot to the aft of the house, so running the return line will require going through the half of the lower section I am currently remodeling.

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But isn't that what you're trying to get away from? The long wait for hot water to the sink?

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I've decided that if I do this I will most likely run the 1/2" return. If for no other reason it would just bother me too much not to do it correctly. But for arguments sake, and I hope you won't mind me making this argument, I agree that having the smaller return line would take longer for the heated water to arrive at the pump, but it's not like I would be standing there waiting for it. It would already be there because that's what the pumps job is for...to have the heated water ready at the faucet when you turn it on. The delay in the time that it would take the heated water to arrive at the pump would happen when the faucet is off and not being used, so what difference would it make, other than the extra work load that it would place on the pump. I agree with you on that point, which is another reason why I've decided not to do it.

But, the user, standing at the faucet, would not notice anything different, other than the water would be immediately hot when they turned on the faucet, because the pump had already pumped the heated water to that point. Yep, it took the pump twice as long to get it there using the 1/4" return line, but nobody noticed that because it happened while they weren't looking, so to speak.

Ok, I know a bit about volume and preessures from my occupation and training, but I'm not a plumber, so maybe I'm all wrong here, but this is just my take on it from what I know. I don't know what kind of pressures these pumps work at so maybe the back pressure that the 1/4" line would create would cause other complications rendering the system inoperative. Theoretically, it seems it should work. But I don't believe I'll waste the money to find out. :D

Cheers... Randy