OT: How do I recirculate hot water to a faucet.

5thwheel · Mar 13, 2010

Our master bath and kitchen are located about thirty feet from the water heater. It takes most of a minute to get hot water to either. I have heard that there is some kind of pump that can keep hot water in demand that does not require plumbing in a return line. Any one know any thing about it?

Wheaties · Mar 13, 2010

Hotels solve this problem with a circulation pump that sends the hot water through a circuit with the hot water taps off that. Naturally, it has a return line.

Homeowners might do this, not with a pump, but with an 'instant hot water' heater beneath the sink in question. They are electric and come on when there is demand.

I hope that helps,

Matt

3t3d · Mar 13, 2010

Yes, there is a pump that takes the hot water line, and pumps it into the cold water line until the water tmep is up to spec.
No extra lines involved. Instant hot water.
Seems wasteful to me.

mark thomas · Mar 13, 2010

It's just a hot water loop, and keeps the water in the hot water circulating so it's always hot. If the pipes are well insulated, the waste is not great. If you let your water run for a while waiting for the hot, you are wasting water, so the hot water recirculation can reduce water waste (may or may not be significant depending where you live.) You cannot create a loop, without plumbing a "return" obviously.

Just google 'hot water recirculation'. There's plenty info on the web.

3t3d · Mar 13, 2010

Mark, the OP asked for a system that did Not involve a return line.
Otherwise you are correct. Don't some systems use a thermosiphon, connecting back to the bottom of the water heater, and thus do not need a pump?

LexD · Mar 13, 2010

This is what I use at home, I have remotes at each location to turn it on.

Water Saver Pump - Mr Solar - Renewable Energy Systems

CalG · Mar 13, 2010

A small under counter electric tank heater or an on demand tankless unit can be a pretty nice thing. When the domestic hot water does make the trip, the electric unit shuts off on the thermostat. No return lines needed as it is not a recirc. system.

5thwheel · Mar 13, 2010

luthor said:
This is what I use at home, I have remotes at each location to turn it on.

Water Saver Pump - Mr Solar - Renewable Energy Systems

Luthor, thanks. This is what I was looking for. I just found the Chili Pepper myself from supplier just north of me. I will have to get two as the kitchen is one direction from the heater and the master bath another direction. I feel I am running nearly a gal. of cold water each time I want to wash my hands. Between my wife and myself I would guess we are wasting at a minimum of 20 gal a day. We get hit pretty hard in water charges each month. I have thought of collecting the wasted water in a bucket for watering plants or flushing but that is a real bother.

Wheaties · Mar 13, 2010

Well I just learned something. I suppose technically, it does have a return, but that return is the cold water line. Interesting. How much do these units cost?

Matt

WSnyder · Mar 13, 2010

Here is the one I use.

https://www.wattspremier.com/products.php?product=Instant-Hot-Water-Recirculating-System

awake · Mar 13, 2010

I looked at installing a recirculating pump when I replaced my hot water heater recently. The only one I could find for under $200 was a unit that attached to the hot water heater directly, with a small valve to be plumbed in at the farthest sink. The thing that made me decide not to install it was that it would continually push warm water back down the cold water line during the times set on a timer, but it would do nothing during other times. My schedule is variable enough that I'd have to reset the timer every day, or set it for a huge range of the day, to get the benefit. Then, when it was running, it seemed that I would wind up with the reverse problem -- having to run the cold water for a while to run the warm water out of the pipe. (I can't stand brushing my teeth in warm water! Yuck!) So much for any savings ...

What I really wanted was an under-sink unit that would run only when hot water was asked for (or a button pushed) -- turn the hot water on for a second and back off (or push the button), wait 30 seconds, and then you have the hot water. IIRC I did find something like that on-line, but it cost a good bit more than I wanted to pay.

jimboggs · Mar 13, 2010

3t3d said:
Mark, the OP asked for a system that did Not involve a return line.
Otherwise you are correct. Don't some systems use a thermosiphon, connecting back to the bottom of the water heater, and thus do not need a pump?

Bingo!! 3/8" soft copper line back to the drain inlet of the tank at the bottom in conjunction with a flow check valve and usually the water circulates by itself. I've run these 60-70' and they work fine. Must qualify this with the fact that these have been basement type situations however. Not so sure that they would work as well with out some elevation change to help the process out. Even a very, very small pump will do the trick. Can be constant circ. or temp. controlled or put on a timer to run only certain periods of the day. Thirty feet should not have that long a lag time (supply lines should be a minimum of 1/2", it often gets "cheated" down to 3/8", especially when someone is trying to save time/money as 3/8" soft is easy to run and lots cheaper than hard piping 1/2", this usually doesn't fly where codes are enforced though*). Most faucets have restrictors installed limiting flow rate to 1.5 gallons a minute or less. Showers 2.5 gallons.

I've yet to hear any good things about any other kind of temperature maintenance device besides the good old-fashioned hot water re-circ line.

Jim

*Referring to copper installs, but is applicable to plastic and other types as well. If you have galvanized, you are SOL. Bite the bullet and rip it out and replace it.

wrenchhead531 · Mar 13, 2010

5thwheel said:
Luthor, thanks. I have thought of collecting the wasted water in a bucket for watering plants or flushing but that is a real bother.

This is exactly why we as Americans cannot compete." TO MUCH OF A BOTHER". We are soft as a country ...not you or me but as a conglomerate we are soft, as a collective we have dumbed down the manufacturing and earning potential of America.
Dave

JimB · Mar 13, 2010

RedyTemp

I bought and installed the RedyTemp 4000N. I put in a push button to start it when I walk in the bathroom. Works well, takes a few minutes. Made in California, when you call to ask questions you talk to an American.

Click here: Hot Water Circulator Recommended by Green Professionals for Efficiency

JimB

stolzdm · Mar 13, 2010

water recirculation

Not 100 percent sure of my math, assuming 3/4 inch line, it takes over 500 feet of pipe to hold a gallon of water. LIke I said not totally sure of the math, but now that I have said this, enough others will check it for us.

Re did my calculations, that was 500 inches or a little over 43 feet.

bob11x · Mar 13, 2010

I recall seeing someone hook up a pump with a motion detector/timer. Then it would only circulate when a presence was detected- saving on heating.

3t3d · Mar 13, 2010

Over 500 Inches of 3/4" line to hold a gallon. About 43.5 feet.

WizardOfBoz · Mar 13, 2010

5thwheel said:
Our master bath and kitchen are located about thirty feet from the water heater. It takes most of a minute to get hot water to either. I have heard that there is some kind of pump that can keep hot water in demand that does not require plumbing in a return line. Any one know any thing about it?

IT seems to me that you either run a return line with a pump (if your heater is in your basement and your user is on the first or second floor, you might be able to use a thermosiphon setup, but again this requires a return.)

Relocating your HW heater would be one approach.

The demand-style HW heater would work without a return. You could have it set up to keep constant output water temp. This way, when the hot water from your tank got to the faucet, the demand heater would taper off. If you've a teenager or a pre-teen girl, this would mean that you'd still have hot water, because when the tank got cold the demand heater would up it's heat output!

One last method would be to reduce the size of your hw pipe. This would give you more drop, but less volume of cold water to purge.

Me, I use the water dispensed while I wait for it to warm to brush my teeth, and I wait the 60 seconds.

Jim

5thwheel · Mar 15, 2010

wrenchhead531 said:
This is exactly why we as Americans cannot compete." TO MUCH OF A BOTHER". We are soft as a country ...not you or me but as a conglomerate we are soft, as a collective we have dumbed down the manufacturing and earning potential of America.
Dave

Dave,

When WWII broke out we moved from Los Angeles to the dessert. After the war ended we moved up to the woods of Oregon and then into a ramble shack log cabin. All those years we did not have hot running water. In fact the log cabin did not have any running water or indoor bath all the years I was in high school. We carried drinking water from town and wash water from rain barrel or from the creek. I was lucky to have shower three times a week at school after PE. I'm 78 now and have gotten used to the convenience of hot running water and am not ready to go back.

OT: How do I recirculate hot water to a faucet.

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