How to Get Hot Water with a Recirculating Pump | Ask This Old House

[@Mike-01234]

I went with the cheap watts $99 blue pump and the passthrough device. I connected the pump power to a GE Smart plug configured it with a motion sensor. The sensor detects movement in the kitchen area turns the pump on for 30 minutes. It will ignore further movement for 30 minutes. This way I don't need a timer having this thing run all the time when it's not needed.

[@eleentskater1234]

Its nice to see Eric Foreman and his dad Red are getting along better these days!

[@hfidek8286]

i guess red finally kept is foot for himself.

[@nnov_tech_chan7891]

Love it. You got straight to the point and explain the thing in 4 minutes.

[@oldcodger]

We had the same problem in our small house, and our plumber ran a long copper line out to the farthest point, and pitched it slightly down to return to the hot water heater. It works by convection, and we get hot water very quickly, and don't need a pump and the electricity to run it. Works great.

[@waterheaterservices]

Valuable tip!

[@rupe53]

We did this years ago when energy was cheap. You do realize the convection system keeps the water warm at the sink 24 hours a day, right? That's why we stopped doing it.

[@williamroberts4913]

I did a gravity line to my farthest sink (slightly pitched return 1/4" copper tubing back to a check valve then going into the drain valve (extended with a brass nipple and a tee for new line) back in 1975 when I built my house. Old plumber friend suggested and it has worked great!!! Not sure if this constant recirculating flow helped extend the life of my Gas Hot Water Tank but my first tank lasted 27 years before I needed to replace it. Then I hooked up this return line into the drain valve on the new tank. This new tank is 17 years old and still working great and I have constant hot water (with no electric pump motor). Granted I did this while building the house so it was easy then. Many thanks to my dear friend Hank the Plumber.

[@purpleblueunicorn]

@@rupe53 But doesn't all that heat loss be offset by less heating of the house, unless you run the line through the attic or somewhere you don't need the heat? In theory it should be neutral energy-wise during winter when you most want to always have hot water.

[@rupe53]

@@purpleblueunicorn ... I see where you are going with the "zero net loss" idea. The reality is most people don't notice if the basement ceiling or various storage cabinets are warmer. After all, pipes run through areas that are seldom used so you are heating unused space. It's considered a loss. Even if fairly well insulated, there's some loss. Also consider that half the year it's summer so heating is not necessary elsewhere. To reduce that loss further, many systems are on a timer, so they don't run when people are sleeping or working. The newest solution is "point of use" heaters rather than a central water heater for the whole house.

[@PatrickKQ4HBD]

4:10 "...so you wanna do it right." THAT'S WHAT I'M HERE TO FIND OUT!

[@ChristianWillis]

I'm surprised this isn't mentioned in more places, but these hot water recirculators also work great for keeping your cold water pipes warm during the winter in colder climates, and helps prevent them from freezing. I'll happily pay a couple extra bucks for the electricity and the time it saves me having to go around dripping the faucets in my house when it's below zero outside.

[@purpleblueunicorn]

And the electricity should not be lost since it saves your it's heat you will not have to heat your house, does it?

[@KevinJDildonik]

No no no. You got a cheap "comfort" type which sends hot water up the hot pipe, then down the cold pipe, so you don't have to installed a 3rd return pipe. You can pay a little more to run the 3rd line, get hot water, and still get cold water. All types save some energy because you're not running a ton of water before the pipe heats up. But they still ultimately cost money all things being equal. For instance, if your home was built with the water heater on the opposite side of the house from the master bath, you might be able to save a ton of money over all of the above if you can relocate it more centrally next time it needs replacing.

[@garyindiana8037]

As most people know warm water freezes faster than cold

[@Boaters_hub]

Thats a great point that i have never thought of!

[@Boaters_hub]

@@garyindiana8037but water flow is less likely to freeze. Hense a river in sub zero weather usually does not freeze

[@worldview730]

3:25, say good buy to any storage item for this sink cabinet, but hello to consistent hot water. I believe in compromise! 😁😁

[@terryvlunsford1610]

In some smaller short runs where water lines are all on the same floor I've seen recirculation lines run without the use of a pump. Of course if it has any distance to travel or multi levels to reach I would assume a pump would always be necessary.

[@DustInTheWindAZ]

I have installed a recirculating pump like the one shown @2:34 of the video. It recirculates hot water, and I have the timer set to run at 15 minutes before and after each hour for 5 minutes to "prime" the hot water. The problem is that somewhere it is forcing hot water into the cold water supply. I have the "check valve" installed under the sink in the master bath (the fathest point from the heater). I verified this valve is working correctly by turning off the cold water at the service valve, and then opening the cold water valve on the sink. The water runs until it gets hot, and it shuts off. But somewhere, hot water is "crossing over" into the cold water line. My research indicates that it could be the valves in the washing machine, but I have tested them and ruled that out. The next culprit could be the single-handled faucets in the house, of which there are three: two in the showers and another at the kitchen sink. The shower valve in the "common" bathroom was recently replaced, so I'm ruling that one out. Yet sometimes (I think when the pump is running), I'll get hot water from the cold faucet at the kitchen sink or the master bath. How do I go about diagnosing this problem? Signed "Hot in Phoenix".

[@brentfromsomewhere]

Unless you have a dedicated return line, all these pumps work by recirculating the water from the hot supply line back through the cold supply line (that's what the T with the check valve at the farthest point is for). Therefore, if the pump has been running, all the water in your cold supply line is going to be warm until all the warm water is purged from it. Instead of waiting for hot water, now you're waiting for cold water.

[@ryanduhaime9086]

What if now your putting hot water into your cold feed of your mixing valve feeding hot with hot. That does not work. And at least where I’m from mixing valves are required.

[@purpleblueunicorn]

@@brentfromsomewhere Does that mean that you'll be drinking water that has gone through the hot water tank? Is this healthy?

[@danielmarra1555]

To be effective, the pump should be installed at the furthest fixture. This way it can sense the hot water circulating and shut it off before the whole return line gets filled with hot water.

[@stephen2220]

Very informative video! Should I install a heat trap when replacing the Anode Rod? The reason I'm asking is because I'm going to install a Watts Recirculating Pump which attaches to the top of the Anode Rod and I don't know if the Heat Trap should be used with this setup. BTW> I'm using the same Water Heater shown in your video. Thank you!

[@Rambleon444]

Here is a tip I did. It took minutes for the water to warm up in our back master-bath so I made a line off the hot water line in the bathroom to outside to water the plants. All I needed has a T-fitting some Pipe hooked up to an electric sprinkler valve that I have on a timer. So I just push a timer button it opens the valve for a minute and waters my plants, shuts off and I have hot water. No expensive pumps, hot water in the cold lines, and it cost less than fifty bucks. I found a programmable digital timmer switch at HD that works great but it is no longer there. So you might have to use one of those twist minute timer switches. You could also just run an on-off valve to the outside and open it up by hand for a min and then close it.

[@kustomchevy27]

Here a cheap alternative also I would see my dad do .get a bucket in the shower let it run till hot and at the end you can dump the water outside to plants or trees.

[@gregolas597]

@@kustomchevy27 Huh, not a bad idea. I rarely use my bathtub in my master anyway, can just dump into that to preheat my shower and scoop water out of there to water plants or whatever. Genius.

[@mikes-wv3em]

i used to plug my shower until the end and save the "grey water" all day for flushing or mopping the floor. then i realized my water bill is only $25/mo and im wasting my time and effort for pennies.

[@oldarkie3880]

This would not work in a climate that has winter where you would have a frozen line and/or an ice rink outside.

[@sadiedodle3998]

Just beware your utility bill may increase substantially. When the water is recirculated it will reheat.

[@WOODYSOOPY]

Please don't judge me but according to my understanding if you use the cool water line supply for return that means you are not going to have cold water now?

[@bobmonday925]

You would install a check valve to stop that

[@jeffyeager1997]

You install a check valve but great question

[@jblaze0382nj]

EXCELLENT DESCRIPTION

[@fortunatedad7695]

This is for the pump set up that doesn't use a recirculation line but that valve that is installed under the sink at the farthest fixture. So this circulates the hot side through the cold back to the hot water tank, then when the water flowing through the hot side is at a certain temperature, the valve under the sink closes to stop hot water from filling the cold side. Now my question is, when the valve under the sink closes and the pump is still going, won't the pressured water be dead heading and cause strain on the valve under the sink? Not to mention increasing pressure of the hot water side?

[@worldview730]

Doesn't the pump shut off if your not using any water?

[@fortunatedad7695]

@@worldview730 no. It's recirculating as long as the timer is on.

[@danielmarra1555]

Pump shuts off based on the temperature of the return line. The timer is on standby for the time programmed.

[@glennmartin8606]

Does it make your cold water out warm water?

[@jessewillett192]

Two Questions: 1) What is the make / model of the final recirculation pump? 2) Is there a recirculation pump on the market that has a wireless remote to activate the pump from another bathroom? Thanks

[@sammoj9836]

I am installing a hot water recirculating pump to my hot water heater, what type of electrical outlet do I need to operate the pump? 15 or 20 ams?

[@josephstruk7974]

Do you need to add a check valve on the cold water line on the comfort system?

[@Chris_dolmeth]

Only for a dedicated recirc line not these ones showed here

[@johndye5928]

Under sink pump is a Taco Model # 006-CT-USK. Amazon price $380

[@donh4806]

I have a water softener system, does it work with this pump . thanks

[@fredbecker607]

It should. The softener is before the water heater.

[@JoeS97756]

Just made an offer on a house with a recirc pump and each of the bathrooms has a wall switch with momentary push I think it's called, doesn't click on or off. The inspector said he thinks it turns on the recirc pump. Is it starting a timer or something? and when you press that button is the water hot right away?

[@josephmcclure6186]

Thank you.very siplified.

[@tonymanero5544]

Pumping cold water from the hit supply, into the cold water line . . . I 4/4inch main has a check valve, wouldn’t forcing cold water into the pipes with a check valve rupture the pipes, or does the water drain back into the hot water heater.

[@Sc00ter]

What is that pump under the sink actually called? I'm having trouble finding something similar. Also, if it pumps it into the cold water line, where does it go exactly, isn't that a closed system?

[@richarddixon1600]

The animation part of this video shows the recirculation pump mounted on the return line just before line entry back into the bottom of the hot water tank (where the tank drain faucet also is located). But, since a water pump pumps water, not air, locating it on the supply side (i.e., before any faucets/outlets) means water will always be available for the circulator to pump. So, if as in the animation the circulator pump is located at the far end of the recirculation system (i.e., after all outlets and right before returning to the hot water heater) wouldn't there be a risk of introducing air into the line when opening a faucet, at least when the pump is running at the same time? If so, air pockets in the line can't be good for the pump, as it is a water pump, not an air pump.

[@squanchy474]

Based on the context of the video, I'm guessing they use check values to prevent air from being introduced after construction...

[@ranp237]

What pump model is the system with activation button under the sink?

[@Innovate2renovate]

Where can I find the system that is at 3:20 with the button to turn the pump on?

[@oldarkie3880]

WHY DID THEY NOT TELL US THE BRANDS USED IN THEIR EXAMPLE? I HAVE AN ON DEMAND CHILI PEPPER PUMP THAT JUST FAILED AFTER 9 YEARS. CHILI PEPPER IS OUT OF BUSINESS AND i AM LOOKING FOR A REPLACEMNT,

[@123chirag]

Can I add more than one check valves for one pump?

[@tonyd3029]

Nice video, Thank you. on parallel hook up with two water heaters how important is to for all the piping be the same length? is there a max amount that the pipe length can varied in size? My out going hot side piping is about 13" longer than the other one in length?

[@ericwheeler2745]

I am having issues with wait times in upstairs bathroom and also the kitchen, of course they are at exact opposite ends of the line. Can I use two bypass valves, or do I need 2 separate pump systems?

[@billbaber6653]

I can wait

[@stevelambaccuratebakerelman]

So i have a 75 gallon power vent water heater and customer says if they take two showers at once and one shower will loose hot water. There is a recirc tee cut into the cold feed of the water heater it does not have a pump. If i install a circulator do you think this will take care of this problem? This is a brand new house plumbed by others.

[@nathannagy1499]

My question is can you add more than one sensor bypass valve? My kitchen which is the obvious problem is as far away from the water heater as it can possibly be in the house, but I also have two bathrooms on the second floor that are almost equally as far if not further away from the tank. Do I just need one under the kitchen sink, or can I put one in one of the bathrooms upstairs to have hot water ready up there as well?

[@chuckblackstock2353]

we have 2 but could easily add more

[@tonymedina405]

What is a brand and model of the unit you have under the sink ??? I would like to buy the unit with the wireless remote thanks

[@WigglesNation]

did any body figure out what make/ model this was? \

[@64savoy]

Rheem 1/25 HP Hot Water Recirculating Pump with Under Sink Kit

[@juliorosenberg9968]

@@64savoy do you need a second line for this under sink pump to work?

[@Rogerabushh]

No it pushes the water into the cold line until the hot water arrives at the sink.

[@DBR00]

Can a circulating pump burn out if I turn off the hot water from the hot water heater and leave the pump plugged in? I think I blew out my pump because I no longer get instant hot water.

[@danielclark8747]

Where do i find the pump u installed with the doorbell button i have to replace a taco system the pump dosent work it has door bell button and remote

[@mildredwebster2822]

Can this keep mobilehome pipes from freezing. Does heat tape and insulation still needed on pipes also

[@mak4374]

We are in Arizona, so we mostly use our water heater as cold water reservoir, so...yeah. I suppose for a small house like ours, we only need this in the winter for our kitchen, which is the furthest point from the water heater. But I think I will get a small 2 gallon electric water heater, and keep the temperature 5 degrees lower than the main water heater, so when hot water flows through it, it shut off.

[@twu42618]

I bought a new house in Palm Coast on December 2022 had same problem, why not install 2 smaller hot water heaters, when they built the house, so don’t have to waste water.

[@JeffEikenberry]

So on the under the sink option, if me entire system is running st 60 psi for example, the increased pressure created by the recirculating pump inder the sink will cause my hot watee heater to refill the existing cold water line versus from the 60 psi line coming in from the city?

[@phototristan]

This is what hotels use so all rooms have hot water with little to no wait.

[@justinsmith8478]

Do I only need one return line from the furthest faucet? Not one from every faucet?

[@anthonythorp7291]

He said only furthest faucet bc that puts hot water NEAR all faucets. But that really depends on how your house is plumbed. Your furthest maybe be an upstairs bathroom yet that hot water only got as close as 1/4 the way from heater to kitchen sink.

[@josepeixoto3384]

My neighbour did that and his gas bill doubled, he called the plumber back in a few months to eliminate it; over 1000 dollars spent to save 10 to 15 dollars a year in water.

[@aintright3889]

Convenience isn't free lol 😂

[@stevenzembriski6761]

@@aintright3889hard to believe i think he is burning gold

[@cycledude240019]

IF this happened, something was very wrong in the way the system was installed. Unless there was a constant amount of cold water being introduced to the loop there would be no reason for the water heater to run to such extremes. A proper recirculating system is reheating previously heated water. Watch the video again and listen to how it's supposed to work and the safeguards required

[@conflubmw1505]

My pipes are under the slab. Turn off the hot at the remote sink for minute, and I have to draw hot water from the tank AGAIN. Whole house recirculation at my house? Wasteful.

[@thomasreedy4751]

Why would he call a plumber to remove a device that you can just unplug????

[@BUSYBAYMENKRISRUMBOLT]

love to see something on geo-thermal how it heats and cools your home, great show guys

[@lindablazier3891]

We have geothermal and we LOVE it!

[@johnhargenrader8972]

What is the self contained pump at 2:03 in the Video

[@TheCodesterr]

Would I need to install the adapter at all faucets in my bathroom, or would one supply hot water to all faucets in the same bathroom?

[@James-bv4nu]

Just the one furthest from the water heater.

[@Foxbat9000]

Hello, great video! Could you tell me the brand of the second-from-left pump on your table, the all-in-on unit with a check valve inside? I am considering a loop system.

[@nwhitlock4380]

Grundfos

[@garykarczewski6678]

What about existing Tankless Heaters without the built in pump?

[@worldview730]

Is there a smaller manifold recirculator that can be used as a space saver?

[@gpabui5256]

should the ACT recirculate pump be installed at the furthest sink (from water heater) in my home?. Thank you

[@James-bv4nu]

yes

[@nortonnewmann3711]

Why not use a temp controlled solenoid valve at the bypass? There would be a delay until the water reached a set temperature, but no wasted water. I'm thinking like in an RV...

[@suprbst]

That's basically what that last one is. It uses a temperature controlled bypass valve, not an electric solenoid. It doesn't waste any water, and the pump uses a very small amount of energy, but your water heater will cycle more frequently to heat the cooled water that is returned. www.amazon.com/dp/B000E78XHG/ref=cm_sw_r_cp_apa_fabc_FTbXFbX09XS2B

[@GG-xs8vt]

I had one installed around 2005...The cold side came out warm. Now I had to wait for the cold water.

[@whatsfordinner7971]

My house has the same problem too. Cold water is warm. There must be something wrong.

[@andystitt3887]

The thermostat on the pump must be broken?

[@kevinjorgensen9211]

check your check valve...

[@rjbishop12]

@@whatsfordinner7971 No, nothing is wrong. If you don't have a dedicated return line and use the cold supply to the sink as the return, then of course your cold water will run warm/hot until you run it for awhile.

[@XtianApi]

That's the bridge style, where you don't run another line all the way through the house. If you want that to not happen at all, run a line all the way with pex and do it that way. No more warm water

[@donstreiff1525]

can 2 recirculation valves (not the pump) under sinks--Ii just had a tankless put in be put in? one in master bathroom under sink and 1 under sink in kitchen?

[@anthonythorp7291]

Without a valve blocking one line, the pump would supply both with hot water at the same time therefore a waste.

[@romano6282]

What if you have a check valve buried behind the wall on cold water line somewhere in the house?

[@anthonythorp7291]

Then you can't use cold line return. I would think BUT DON'T KNOW multiple family builds would have multiple check valves. So that is something to check first.

[@alamalam554]

Where I can purchase and price?

[@americanhindi]

Where do you find plumbers and contractors like these guys? Everyone I meet are just waiting to rip us off as quickly and lazily possible.

[@mikes-wv3em]

(LAUGHS IN GOETTEL)

[@tommason4702]

People, if you want warm water coming out fast at the faucet, simply make the loop without installing the pump. Pump is not necessary at all. Once the full loop is made in the warm water line, warm water will circulate through the warm water pipe by convection effect where hot water expands in the heater and forces the water to move through the loop to colder region and back into the heater and continue the cycle. I had a water pump installed but failed and I took it out and bypassed it and I still get nice hot water very quickly better than ever before with no headache to deal with failing pump or timer. Pump and timer are expensive and difficult to maintain and absolutely not needed in most residential use. If you do not believe me, try first before you take the trouble of installing one.

[@flat-earther]

Interesting, does it work like a passive solar water heater

[@paulwindisch1423]

You are correct, however, there is no shutting off that type of setup and you are heating water 24/7. The pump has a timer so you can program it to only run during peak use. And truthfully, the Watts/Grundfos pump is not that expensive.

[@truebengalsfan]

Works this be almost as good as tankless water heater

[@johnbenson3174]

Can this work on a house that is plumbed using a mono block system, or just a series plumbing

[@chrisw5436]

Some information is missing in this video, not all re-circulation systems will work with tankless heaters. Watts will not work because for tankless a higher flow rate and a return line is needed.

[@whowawoo]

Am I missing something? How do I get cold water if hot water is running thru my cold water pipe? If I open the cold water pipe, don’t I have to wait until the hot water empties into the sink? Before I get fresh water?

[@JohnODonovan1]

How do i do it right?

[@farrakhjavaid786]

Sir i want to ask that we have a pump near water heater. I think that pump will suck water and if we turn on tap the pressure will be less in that tap because pump will suck water for recirculation

[@anthonythorp7291]

No, if at the heater it is not in the sinks supply line therefore pressure/amount unaffected. And you don't run the recirculating pump while using water therefore again pressure/amount unaffected.

[@jjf609]

Does it wear out the pipes faster?

[@Gixxr11]

No, it wears out water heater possibly. More gas/energy use. But, you'll have hot water.

[@robertmckee8453]

Why is a check valve needed with a recirculation line? The person talking implied it was to stop hot water going to the cold water line (as though this was not allowed).. I would be nervous about doing option two where hot water pumps into the cold water line, because I thought “hot” water was not fit to drink (so wouldn’t we not want it in the cold side at all?).

[@ElectricGears]

Hot water in any modern plumbing system is perfectly safe to drink. In some old systems they used an unsealed, unpressurized tank in the attic (as part of the steam or hot water radiator and boiler heating system). kzbin.info/www/bejne/fpermIirlJ1-naM Recirculators would not work in that system.

[@yolandacastillo2500]

Can you install the pump at the bottom of the heater instead of the top?

[@yzhang8629]

Yolanda Castillo the pump must connect to your water line. In the video, water lines are on the top of the water heater, so the pump goes to the top. I assume the pump will go to the bottom only if the water lines are at the bottom

[@jwhite4]

@@yzhang8629 It should be able to be connected to the drain at the bottom of the tank. The hot water will always leave via the hot water outlet. Doesn't really matter if the cooler water replacing it comes in via the cold water inlet, or the drain line.

[@marthamccraw9463]

How to hook up circulation line to new faucet

[@katmeyster]

Our farthest fixture is less than 50 feet away from the hot water tank and it takes a minimum of 10 minutes to get any hot water, and it never gets as hot as the rest of the house. And we're on well water in a dry climate -- so not wasting water is very important. I hope this might work, but it seems something else could be the problem. Our house is less than 20 years old.

[@bobbryant3698]

katmeyster You might have a stuck mixer valve. If you have two individual faucets for hot and cold then thats not thr problem but if you only have one that mixes the two then it could be.That will cause the problem you mentioned. It will never let the hot water get in to the max.

[@yzhang8629]

Bob Bryant it may be simply caused by the distance. Hot water always wants to give heat to the cold surrounding environment, so longer distance = more heat loss = lower temperature at the faucet

[@chriswithrow3107]

@@yzhang8629 10 minutes though? No something is seriously wrong.

[@worldview730]

@@chriswithrow3107 Yes, too long for everytime

[@KevinJDildonik]

If anyone has a problem like this. This is NOT normal. Even a pretty large house, built very poorly, should take 2mins max to heat up in the dead of winter. And even that is a nightmare scenario! Americans are just used to really, really bad cut-rate plumbing jobs. A lot of guys are using 100-year-old knowledge in a world where energy saving technology advances monthly. You have some kind of thermal loss happening. Like maybe your lines are bolted to big metal beams, so the beam is acting like a heat sink. Or the pipe is running a long circuit, like it got routed the wrong way to get around an obstruction. My house has 2 stories and a basement, in an area that gets to -20F, and my water heater was installed on the other end of the house so the pipes travel a long distance in the basement before coming up through improperly insulated walls. And the water STILL takes less than a minute to warm up. I cut it by a solid 30s just installing $5 worth of foam pipe wrap. And no that doesn't "cause rust" unless some leak is getting into the foam. The pipes usually rust when they get condensation from sudden temperature changes, and it helps when they're exposed to both air and water. The whole purpose of the insulation is to prevent those shocks. And keep the air and water off the pipe.

[@PJFinster]

Will these systems work on a house fed by a water well?

[@kevinjorgensen9211]

yes. no problem. have had one for 20 years on my well water system.

[@Diehard65]

So now by using the existing cold water pipe to receive some of the water that has gone through the water heater and picked up various materials from the water heater(magnesium for one), how long do I run the cold water before I can drink it or use it to brush my teeth. For example, it is recommended that hot water not be used in cooking, etc. for a reason. In fact there were some that felt that this shouldn't be allowed as it constitutes a "cross-connection".

[@yzhang8629]

Diehard hotter water dissolves more stuff, like lead and other contamination in the pipe, I think that’s why one should not use hot water for drinking/cooking.

[@bolgerisdashizz]

Brilliantly explained. I have subscribed

[@roypayne4811]

And it's important that your hot water and recirc hot water piping is insulated, right? Cause otherwise your heating the ground below your slab or crawlspaces.

[@davenone7312]

Thats the problem most existing homes have no access to insulate those pipes so alot of wasted energy just to keep the supply and return lines full of hot water.

[@yzhang8629]

When you flush all that cold water down the drain, and when you are enjoying your hot water, hot water in the pipe is always heating the slab or crawspace. With the same temperature setting on my water heater, my shower hot water is colder in winter/when ground temperature is low.

[@MikePusley]

Is there anyway to make this work without a return line. Impossible to install in my home without major expense

[@mikebaca6312]

Mike Pusley Look at the last part of the video. He tells you exactly how to do this without a return line.

[@anthonythorp7291]

Yes, they said back feed the cold water line. Just make sure water can make it back to tank. No check valves in path.

[@daetfedavisagain7304]

will that work for electric tankless hot water heaters?

[@naomi-g]

yes

[@5thGenNativeTexan]

The one thing I continue to not quite understand is how hot water will be immediately available at all my faucets/showers, etc by putting the one check valve on the sink at the furthermost run from the water heater. It would seem that there would still be some branches/legs of pipe to the other faucets/showers that still would have some cool water in them, and that really only the sink with the check valve is the "immediately available" sink. I have a two-story house, 4 bathrooms, kitchen, etc, spread out over 4600 sq ft. Will I really get hot water immediately at every faucet/shower in the house?

[@matthewfry133]

"Immediately"? No. But the distance from the other faucets that branch off between the farthest faucet and the water heater to the loop where you install the check valve will be much shorter than the distance back to the water heater. Usually that's a very short run so your wait will be very short.

[@ElectricGears]

@@matthewfry133 Additionally, the branches to a sink would typically be 3/8" (the smallest diameter pipe) instead of 1/2" or 5/8" so the volume of cold water sitting the pipe that you need to waste out of the faucet is significantly reduced.

[@paulwindisch1423]

You can install more than one of the thermostatic valves. I have three branches total, so I installed three valves. One in the master bath, one in the guest bath (opposite direction of the master) and one in a bathroom upstairs (the other upstairs bath shares the same branch, so both of them are served by that valve). All of them work with just the one pump installed on the water heater. The kitchen sink is in between the water heater and the master bath, so it also is nearly instant warm water, as in by the time you count “2 Mississippi”.

[@5thGenNativeTexan]

@paulwindisch1423 thanks very much!

[@TimS57064]

My concern then would be how much electricity does the recirculating pump use? We have this problem in our house and I have been thinking about installing one of these for quite some time, yet have thought that, yeah now our electrical bill will increase, but by how much? There are only 2 of us in the house and use between 4 and 5000 gallons monthly. I believe this will save us money on water usage , yet then the electrical bill will increase. We do have a gas water heater though too so the gas bill will increase too because of the cold water being put back into the water heater. So this seems to be a win lose situation right? Thanks

[@NESEP76]

Here are some rough calculations for you. This pump consumes 25 Watts when running. If you ran it 24 hours a day it would consume 600 Watt-hours. I pay 7 cents per kilowatt hours. So I could run this pump for about 4 cents a day. I doubt you will see that in your bill. As for the cold water in the hot water tank, if you only run the recirc pump when you need the hot water at the sink, then you will not be increasing the amount of cold water going into your tank at all since the water you used to dump down the drain now goes to the tank instead of cold water from your source. The trick is knowing how to set up the timer. My preference would be to use a on demand switch for some sort. Also remember that every BTU you lose because of hot water heats your home. This would benefit your furnace during late fall to early spring.

[@TimS57064]

Thanks @@NESEP76 ,I had forgotten all about this.

[@NESEP76]

@@TimS57064. You are welcome. I'm looking for solutions to this as well. I've found that it helps to be armed with facts to filter out the noise of certain comments. Good luck.

[@beckganiyev5537]

Can recirculating pump be installed on manifold system?

[@jaredpelski8049]

Looks like a Bridge valve would be needed on each fixture that has hot and cold. Only problem is you then have softened water being pushed in the cold lines.

[@peterryan7827]

Just a curiosity question ,most of the older property here have the hot water fed froma loft tank which makes it low pressure,where as the cold water mains comes in at high pressure are these pumps desigen for both,and what happen when they mix , like the set up under that vanity unit ,.The return pumped system we have here in larger homes and hotels etc,but all on the same pressure,

[@jwhite4]

The cold water line feeds the hot water heater (and then maybe a storage tank). Unless there's some custom plumbing (pressure reducer), the hot water pressure should be the same as the cold water pressure.

[@edfx]

I have 100 feet 3/4" hot water line. I plan to use 16mm al-pex (between 3/8" and 1/2") as circulation return line. Change my mind.

[@grizzlysrm]

We are building a new home that is suppose to have a 50 gallon water heater. What is going to be more energy efficient for us? To replace the hot water heater with an on demand system (insta hot) or a recert pump?

[@rski1036]

Get a heat pump type hot water heater. As long as it's installed in your garage or where air not too cold it will take heat from the air and put it into the water. The bonus is it leaves the garage a lot less hot.

[@sceamson]

storing hot water is past day technology. On Demand tankless water heaters (like Renna, Rheem, Navien) can do your job in a best efficient way.

[@jwhite4]

@@sceamson If it's a tankless HWH to replace a heat pump or conventional HWH, that won't solve this problem - standby heat loss in the pipes. That still needs to be flushed to get to hot water. I'm not sure if the "Insta Hot" is like one of those sink-mounted hot water heaters, where it's actually a separate heater at the point of use. I'm not sure I've seen them that would drive a shower.

[@allover5622]

If I understand the mechanics properly, this means at times we will be drinking water that has run through the hot water heater? Is this now safe to do?

[@rpsmith]

No, it's not safe to drink or cook with! Drain you hot water heater and look at what comes out. If that doesn't convince you, remove the drain valve and look inside your water heater. The only safe way to do this is with a separate return line to return the water to the drain valve on the bottom of the water heater. Never use an existing cold water line as a return line!

[@chuckblackstock2353]

@@rpsmith Ir is the same water. and safe to drink. the residue in the water heater is usually calcium chloride which is in the water anyway.

[@rpsmith]

@@chuckblackstock2353 -- Watch this and see if you still feel the same way: kzbin.info/www/bejne/oXLdfKepa7yjZ7M

[@alchance662]

Using existing cold water line return, that bypass junction is a bi-metal valve that keeps hot water from entering cold side, AND, stops water flow back as long as it is Hot water. My Q - what happens to pump when Hot water cannot flow past the bi-metal valve? Does it burn out?

[@yzhang8629]

Al Chance possibly, if the pump has poor/no self-protection. However, the water pressure in hot and cold line should be pretty similar, since the water comes from the same main shut-off valve, so I assume the pump doesn’t need to work too hard to add a little pressure at one side over the other side

[@chuckblackstock2353]

@@yzhang8629 the pump is only 25 watts and there is no resistance.so no extra load on the pump. i am Electrical eng and I wish I had done this sooner

[@ocrun6765]

Seems like the trade off for constant hot water is that the cold water side will become warm since it's being used to recirculate below temp threshold hot water from the hot side.

[@ElectricGears]

Their illustration is unclear for the whole-house recirculator system because it does not show the cold water line. There are actually three line going to the sink: Cold, Hot, and Return. The pump moves hot water from the tank through the Hot line and when the sink is not in use, it goes back to the tank via the Return line. Nothing moves in the cold line until you open the cold tap. For the under-sink system, the pump has a temperature sensor and shuts off as soon it senses hot water. This means that once hot water reaches the sink it will not continue to pump it back into the cold line.

[@greglake2522]

I agree with the pump using electricity but if your on a well, your well pump is running waiting for hot water to get to the faucet wasting electricity and water without the convenience of hot water. If your on a metered city water now your paying for the water your wasting, electricity might be cheaper plus the convenience of hot water.

[@rupe53]

Greg Lake … I think you misunderstand the concept. The pump does NOT use any water, nor does it flush it down the drain. A properly installed system will recirculate the water within the pipes and return the water via the cold water pipe, then shut off when hot water reaches the sensor. Basically this takes the place of you standing there running water down the drain while waiting 30 seconds for it to get hot, but all that cold water goes back into the cold side (for consumption elsewhere) so not wasted.

[@davidturlington1958]

what can I do since we have a tankless hot water heater?

[@palillo2006]

David Turlington you can install a point of use water heater. Basically they are tiny tankless water heaters that install under the sink.

[@JSH1515]

Should use spring check valves not swing gate check valves

[@Sarfrozkhan]

i have a query, a system like in India we usually have an overhead tank and from there the water is supplied to the whole house. now, how can we get the hot water to each faucet ??

[@josephmcclure6186]

Run a whole loop to each fixture from the attic down.

[@TheWilferch]

Can this idea be used to avoid pipe freezing ???

[@mikebaca6312]

Wil Ferch Yes just make sure pump is on during very cold temperatures

[@jwhite4]

@@mikebaca6312 I would say only if the cooler hot water is pushed into the cold water line (vs having a dedicated return line). I'd think that's more likely to freeze.

[@1weirddoe571]

How does the pump not burn out when the valve is closed and the pump is still trying to push hot water against a closed valve?

[@paulwindisch1423]

It’s just a circulation pump, not a positive displacement pump. It does not produce much pressure. It only draws 25 watts. It will not burn out.

[@1weirddoe571]

@@paulwindisch1423, but it has to produce enough pressure to push against the cold pressure, right? By how many psi does it have to be greater than the cold pressure?

[@paulwindisch1423]

@@1weirddoe571 if you were to measure it, it’s probably only about 1-2 psi.

[@ricoludovici2825]

@@1weirddoe571 The water is not turned on. It simply chases the water already in the pipes around in a circle. The hot water that is not hot is reinjected into the cold side.

[@johncoen1468]

Can anyone tell me why secondary return has to be plumbed with copper and not plastic??would like to know why

[@wholeNwon]

So you're pumping water that was in your water heater, which is not recommended for either drinking or cooking, back into the municipal water supply? Yes, I realize that the importance is relative to the volume, the size of the house and proximity of neighbors. What if there is a check valve in the cold water system and no expansion tank at the water heater (hopefully a rare mistake)? Guess that's where the TPR valve would hopefully save you.

[@James-bv4nu]

If you're concerned, then install a dedicated recirc line back to the water heater from the farthest point.

[@wholeNwon]

@@James-bv4nu I think an expansion tank would then also be required.

[@charleskeuhn7383]

I would like to see this updated to show a system in a smart home. I have Alexa and a few smart devices such as lights/outlets and a few other things. An integral timer is therefore a wasted expense. I would only have this pump run a few minutes an hour during my highest period of demand. Installing an electrical outlet under my sink with a smart outlet ($5-10) is not a bad DIY project and under $30 total. Then I could just run it when I say "Alexa, get the water hot." Yes it would be nice to save the water while keeping it to a minimum increase in pump and water heater energy but I am interested in convenience as well. Here are some of my questions: I am unclear on why a check-valve is needed (on the undercabinet option). Also, anyone had issues with the recirculation system not working because of a heat trap on the water heater? (I have seen that mentioned elsewhere). Finally, I would like to hear from people who have these systems about how much of a problem the cold water lines filed with warm water is for them.

[@rupe53]

One thing nobody mentioned is wiring the pump to the bathroom light so it only runs when someone goes in there. Could also be done with a motion sensor, which would give the system a signal to start when someone goes into the bathroom during the day when lights are not needed. Either way the system only runs on demand, which would be helpful in a house where people keep an odd schedule and a timer just doesn't work well without having excess run time. BTW, anyone catch the extension cord being stored on top of the fire extinguisher? That's a fire code problem!

[@stevem6711]

I wouldn't do it that way. You can find a remote switch that the pump will plug into with multiple remote controls. Put a control in each bathroom and activate when needed. Much easier than what you're suggesting. Find this device on Amazon.

[@notavailable.000]

smart

[@HotNoob]

that's a great idea. i might do that.

[@tripjet999]

@0:52 - Hmm, we have a COLD-water heater.

[@anthonythorp7291]

Well, you wouldn't heat hot water I guess.

[@ryanduhaime9086]

If you have a dedicated return line this works great yet a lot of fuel gets burned . If you don’t have a dedicated return line and at the tee at the fixture that’s ok unless you have a mixing valve that will scald you if you are showering and the cold water feed to the mixing valve becomes hot mixing now with hot to get 140 and scalding to homeowner. From a tech

[@Solerf1]

I have 60 psi at the cold line. Do you think a normal recirculating pump will be enough to push the cold water in the hot line against that pressure?

[@rjbishop12]

@@Solerf1 But your hot supply is at the same 60psi pressure. The pump is simply recirculating water that is all at the same pressure.

[@paulwindisch1423]

That’s not how it works though. The valve that connects hot to cold under the sink closes at 98 degrees, so one will not be scalded.

[@MightyMorphinMatt]

This seems like a lot of extra work and cost when you could install an instant hot water heater at the faucet. What are the benefits of this setup?

[@dfinma]

+Matt Foley You would need an instant water heater at each sink and shower (and dishwasher and washing machine). That might be okay for a [very] small cottage but once you get into a more typical size house a recirculation system is a better choice.

[@MightyMorphinMatt]

+Doug F Thanks that makes sense.

[@sceamson]

Electricity bill cost more than the gas.

[@NoPlanC]

@@sceamson Not true! Electric pumps typically start at only 1/40th of a Horsepower, plus can be set on a timer or a demand system so they don't run 24/7.

[@natyong]

@@NoPlanC Instant hot water heaters at sink most often use high draw electricity. Yes pumps are a low draw but this comment thread is about tankless installs at each point of use.

[@gunnersecuador7515]

Sounds great, the only problem I see, I have never been in a house with a 115 VAC outlet under the sink..... So now you need an electrician added to the plumber, added to the costs of the pump etc. Starting to sound less attractive at this point.

[@michaelandrews934]

Nah, there is a nearby junction box you can wire to a socket. This is really the most simple electrical task every homeowner should know how to do, and it will build your confidence in understanding the electrical system in you house.

[@ginnawitters-evans5156]

Just FYI but usually there is an outlet under sink that's what garage disposal and dishwasher are plugged into.

[@fiftythreeer4696]

Does anybody know the name of the very last pump?. The one that was under the sink.

[@PaulGoess316]

+iiloverr I am pretty sure the brand name is Taco.

[@Nicefswagg]

Looks like a Grundfos Circulator Pump.

[@PaulGoess316]

The one on the table is Grundfos, under the sink in the cabinet is a Taco.

[@juliorosenberg9968]

Are there single pipe recirculating pumps?

[@anthonythorp7291]

No, water has to go somewhere.

[@64savoy]

I would like to know the make and model of the 2nd unit they showed and mentioned. But can not depend on the check valves to be trustworthy. Mine always seems to need an internal cleaning.

[@independent900]

Did you ever figure out what the 2nd unit is? It wasn't very useful for them to show you specific product and then not bother to tell you what is it is. Very frustrating.