Installing a Recirculation Pump for instant hot water and saving water 

Very good, clear, easy to understand and easy follow instructions. Thanks !!

A lot of this working efficiently for comfort surely depends on the differential in temperature between on/off on the pump thermo stat. If it's only a matter of 1-2 degrees the pump will be constantly pulsing the cold line with warm-hot water during the time frame the pump is set to run, which causes an issue if you have the cold open too. I guess you could hope to rely on the cold neutralizing the entirety of hot pulses. I'd be interested to know how well it works in actual application?

Great video, thanks!

helpful video. One suggestion I learned from a plumber. Leave it always ON, plug into a smart plug (available almost anywhere for under $15), and control it with your phone instead. You can use your phone to program it to turn on/off whenever you want, from anywhere. Way easier than using the 1970's dial.

Nice video! With this setup do you get much hot water when you turn on the cold water faucet? Do these units have a thermostat or just a timer. Thanks!

Do you have any suggestions for a recirculating pump and timer for a "solar" hot water heating system? I would like to recirculate water through a homemade solar collector, tied into my water heater, and back thru my water heater at about 10 intervals during the hottest part of day for 5 minutes each interval. I need a pump recommendation and a timer that can be set at shorter intervals. Under regular use, the water comes from the hw tank, not the collector outside. I'm in TX heat is free.

I do not do that, I am a Professional. Code requires a separate shut off for each fixture. Do what you will, but you may regret it.

Really nice video. Simple and to the point, even mentioning how the seal is made as well as what to do if the stem leaks. I am a plumber and appreciate people who spread the knowledge.

I would make the power outlet tied to the light so the pump only gets power when the light is on. I always turn the light on when I use the bathroom.

Yea, if I had endless time and resources our site could double or more the content and then viewers then we could sell this valuable service to the public for a win win trade. Till then we dream of going viral... Do you get e mails thanking you ?

So if I understand how this works, you save water by not having to wait for the hot water to heat up. But aren't you losing water by waiting for the water to cool in the cold side? We also are heating up the cold side piping which is typically not insulated so energy will have to be made up by the hot water heater as it recirculates through it? Especially in the colder months of the year.

All I can say is I'm extremely happy with my Hot Water Lobster. I had a pump system in my last house. The pump system filled the entire cold water pipes with boiling hot water for the entire time the pump was running...it was impossible to get water cool enough to shower in...and the pump only lasted 2-years before failing. Oh well, to each his own.

My Laing LHB08100092 re-circulation pump stopped working after about 3 years. I hear the motor running but no hot or warm water as it used to work. What could be the problem?

Installed a circulation pump at my house today because of this video. Ready for instant hot water this winter :) Thank you for the great video.

Well, in theory this thing will save money (and water). In Canada this pump costs some $1800. There is a lot of water to waste to make up for that kind of money, I hope you understand what I mean.

Has anyone done a payback analysis on the water savings vs the cost of the pump, and including the extra cost of heating the water? Obviously there will be more heat lost from the circulating hot water. Be sure to insulate the pipes. How much water will be lost when you have to let the cold water run to get a cold drink? This might make sense for a public washroom where you don't care about getting cold water. Especially with low-flow faucets that take forever to get hot water from a distant heater. In this case, it might make more sense to install a small point-of-use heater.

Commenting from the UK but I do have this problem - however, our cold water comes straight from the main line outside in the street - I don't have a cold water tank. Would this still work?

This was a weird RU-vid recommendation. 10,000 gal of wasted water is highly questionable. That's over 800 gallons/mo. There are some months we don't even use that much water, let alone waste that much down the sink waiting for it to get warm...

Water and gas, which one is cheaper? You may end up to pay more on gas than water! My best guess is if you have the return water from the circulation, you will definitely have the gas stove reheat your tank or your tankless. Water in my area is still much cheaper than gas!

This is just a recipe for legionella, most idiotic thing I have ever seen. PS flex connectors very amateur, regards from the UK

We moved into this house (built in 2010) that has a tankless water heater. I looked under one of the bathrooms sinks and found this extra house that is connected (on the side) to the water hose going to each faucet and then the extra hoses join together in a small box in the center, under the faucet. Any idea what it could be and is it unique to tankless?

Hi Everybody. Does this recirculation pump work in secondary return pipe hot water system? We have recently build a welfare facility building (Building size approx 60m x 30m) with a secondary return pipe. I wonder if this kind of pump works with this kind of system, if it works what's the proper name of this kind of pump and where can I buy it? I am from UK.

Interesting...I found a similar hot water recirculation valve that is much esier to install. Thermal convection circulates the water-so no pump is required. I installed it several months ago in less than 15-miutes and it has been working great! If you are interested it is called the "Hot Water Lobster". Billy-D

I’m want to install this pump in my kitchen but I have a boiler suppling my domestic hot water. Will this pump work the same way

you got instant hot water, but no more cold water, because the hot water circulates back thru the coldmwater line.

When the pump turns off due to temperature being met and stops the flow of water, how much does the temperature have to drop before it turns on again to bring more hot water along? When it does turn on again, isn't it going to pump moderately hot or at least very warm water down the cold line? What if after that you want cold water? Won't the cold line then be full of mildly hot water?

If i understand you i need to install pump in my hot water recirculation line? My goes into the bottom of tanks drain valve have a tee installed.

Where we can buy this pump, name of manufacturer and model number of pump????

This should never be used will make you sick, any hot loop should be dedicated, ask me why.

i don't have a water tank just a boiler, if I put this under the sink will it also give instant hot water in the shower? or will I have to put one also in the bathroom?

Wouldn’t you want to install this on a second floor fixture? Farthest away?

My husband and I just installed this exact product today and I hopeful but skeptical. We completed the install in about an hour (we were being goofy or it would have been faster). I thought it was going to take an hour or more for the system to kick in and start working but we had hot water to the bathroom sink right away. We used to never get hot water to the sinks in the bathrooms, it took too long to wait for it to heat up and the showers took 5+ minutes to get tepid hot water in the winter but it was heating up in 30 seconds. So far I love this and wish we had known about it for the last 12 years that we have lived in this house. I'll update my post if anything changes but so far I love it and it doesn't hum any more than a refrigerator, something I can certainly live with! Looking forward to hot showers and lower water bills!

This pump can give hot water to all faucets in the house or just this one?

Your not trying to circulate water thru house, your trying to collect solar heat right? The pumps are same but the consequence is making thermal expansion in your hot water system. It is complex and can have hazards. Look at a typical Solar Water Heating layout and copy that if you are inclined, but I have learned limits in DIY and design of Solar Water heating is on the other side of my willingness. Having said that, "Home Made" Solar designs do exist online. Be careful steam burns.

What is the name of the pump !! I am in Spain were can I buy in Europe

T&P valves are not for operation, that is like using air bags for brakes. A Thermal exp. tank is a good addition to any home where pressure at street is over 80 psi, or a check valve is used in the system.

Claude, thanks! Greg

Thermal siphon will only work if pipe is pitched, most places are not pitched, so you got lucky. The new code has prohibited 24 hr. circulation because the heat loss is prohibitive, literally.

I think the Hot Water Lobster has issues and it is not fair to suggest people buy it just because it offers a guarantee. I guarantee that gravity is a given as is thermal expansion, not because my of my opinions, but physics. The lobster must need either or both to succeed in circulating and if so some people will go to a lot of un needed effort and grief and postage or other expense just to try your product. I caution consumers "Are you feeling lucky" Greg Chick.

Will this type of install also work for a tankless water heater?

This Lobster could be a monster for a house that needs a pump and this Lobster is bought and does not work. In order for it to work there must either be pitched pipes in house, or thermal expansion pushing the water around to loop it. I suggest if thermal expansion is pushing water there is trouble head with a flood from thermal expansion pressures trapped in piping system. A pump does not create such pressure, a pump just circulates creating harmless pressure in doing so.

I suspect the Pump install was poorly done. Normally the circulators last 15 yrs or more. Also the controls that work the pump are the reason the pump over pumped. I suspect the controls killed the pump and caused the water to be hot on cold side. As a question as to the shower that had cold water that was made hot, is that valve a Moen or a Mixit brand ?

but then you have no cold water do you? Seems to me that if you circulate back through the cold you will have hot in that line as well so you have to run that one to get cold to cool down your hot?

Dear Greg, I just watched your video and found it interesting--thanks! This same unit is installed on our water heater and has been for 5 years... But I think the water heater is going out and will only heat to hot if all the way on "very hot". Unlike it was so very hot even on vacation mode when new! So, I really need to have that looked into. I am by no means savvy in these kinds of thing by far. However, since this pump is installed shouldn't it somehow heat the water even if the actual water heater is going? Or does it just hold it and or recirculated it. Or, am I missing how this device works all together. Only when water is very hot from heater it still comes out hot within 2 seconds and once again probably the water heater and can't circulate what is not there. I may have answered my own question, but thought I would ask the expert. Many thanks....

i could see if u were running another line back to the water tank but including the cold water line makes no frickin sense,

This makes more pressure for hot and cold water?

Thank you for this video! Your instructions are very clear! Would you consider posting a video showing how to install the pump under a kitchen sink that has a garbage disposal? Also, would you explain further WHY the pump works? Thanks again!

"Simple Physics" are simple, but not always safe. Hot water expansion has been such an issue for "ever" in the 30's buildings were blown up fron expansion. Watts Brass Mfgr. designed a pressure relief device to protect buildings from this. A movie was made back 70 yrs. ago on this as well as today myth busters did a video on the issue. I do not suggest the Lobster creates this pressure, I suggest the Lobster uses this pressure and that if this pressure exists that in it's self is worrisome.

Yes I get a lot of e-mail and comment's thanking me it's really up lifting and make it all worth wild very humbling. And at the same time I'm just like every one ells. I find a lot of great videos on here that help me. Like work on cars, electrical, Learning computer software program how to. It's endless. Any way you have a great day.

Do you really need one when you live in Arizona?

Pumps are sized according to need, not is another person uses that pump. I use the Metlund Demand pump system when I can, go to the site ACT, metlund demand . The Got hot water.com is one address they have the full line of pump systems there. A common pump is only part of the system.... the same pump can have a timer, aqua stat, or both and can have unions or not and can be 1/2" or 3/4" and can also be for screwing on the pump or soldering on the pump, all have different model #..

I recommend ACT Demand circa. pump in general. If you want a circa. pump on a tankless water heater, the Mfgr. recommendation takes priority over my recommendations for warranty reasons, if they specify. The layout of piping might require a high head pump, or the pipe size might require a pump designed to move volume, not pressure..... Plumbing design is different than opinions, it needs to be based on protocol set by physics.

will the circulation pump at the furthest point help other ,closer (to the hot water tank ) hot water draw ?

Pumps are different in the features they offer, some have unions, some have aqua stats built in, some have built in check valves, some timers, some pig tails, some have higher head capacity (pressure). some are 1/2" others are 3/4", flanged to connect to pipe, or pipe thread, some have ball valves built into the unions that are with either threaded, or compression. $150 gets you a pump only, $500 gets you the whole she-bang. Cast iron or bronze, or Stainless steel!.

Does this work for a tankless water heater? I am wrestling with that right now. The heater makes the master bath hot enough, eventually...but the rest of the house is REALLY hard to heat. Ideas?

Possibly an on demand pump set at desired pressure activated by flow switch. The Flo Tech company makes them. Just put it on the way to faucet below the sink. They are the size of a liter bottle.

Yes, the thermostat valves can go anywhere, and several, not a problem. The Laing makes a unique pump and a timer is a good feature as is an aquastat. The timer can be just one of those plug into the wall for a lamp sort of thing or built on the pump. One issue with multiple floors is air in the line. Purging out all air is needed.

Once you get the hot water to the bathroom, the hot water for all fixtures there and on the way there will have closer hot water.

I use temperature sensors, one at the tank on the bottom where the coolest water sits and the pump pulls from (drain port). The other sensor at top of panel where it is hottest. the two sensor wires go to a Delta T controller that is a simple box that says "wow it's 10 degrees hotter at the panel, circulate the pump." using a relay inside the controller that the pump is pluged in to turns on the pump any time heat is there greater than tank bottom... Timers are not very smart..

Why you always mention !!made in usa!!

It depends on how the piping is layed out. The full length is circulated, but branches are not. there are pumping systems that do that, but more is needed to be known

I am well aware of PTRV and well aware of what happens when they fail I am formally and field educated for decades.

This is one of many circ systems,please let us know if you have anything to ask or say about your needs, your layout or experiences.

Your question is too open, in what application and from what pressure to what pressure and with or with out an electrical outlet in and how much space available and what price range?

Don't waste water, get Circulated Life is too short to wait for water, there is an App for that!

A switch is a great way to go. Yes, this is a package product from ACT Metlund circulator see my 2 videos and link to that product video from them. I think a switch method is best if you use a pump designed to work fast. Once again the Metlund. Greg

Continued, Some have floating impellers and no seal on motor shaft while others have a cartridge for a motor and the pump is separate. Laing is a fine local to san Diego pump. Grundfos is a world wide pump having far more options. The De-mand Metlund unit has it all, get one. Or tell me your application and details and I can help you decide... like I said, Metlund.

Due to using the closed loop system within the hot/cold water plumbings, it is very important that the water heater is clean because you will be drinking from it. This hot water will be circulated within your potable water system as well. All the sediments, corrosion, calcium deposits, rotten egg smell (if any) will be part of your drinking water. I would flush the water heater at least twice a year and change the anode rod every year if you have a recirculating pump.

This was a clear and informative video. Thank you. Had 2 plumbers cemo out and try to get to buy a thankless water heater. My water heater works and gets hot water everywhere. However hot water to the kitchen and guest bathroom sink takes forever. Neither one mention this option. Smh. $300 for this pump or $4000-$6000 new water heater.

Grundfos Pumps sells the valves at Ferguson supply houses, search comfort systems, they come with the pump.

most everyone needs this. done correctly it saves water and power as well as time!..

Hi, I’m worried about the pressure on my cold water line and the pressure of water being forced backwards- any risk to my lines busting? Thanks

Is it better with on demand button?

Metlund Dmand pump system is totally equipped to do all of this correctly and to code.

I put one of these in my house 20 years ago and its still working fine.

Can this pump be used on a system that has a tankless heater

I believe the Hot Water lobster offers a Money Back Guarantee. However, my house plumbing is not pitched. If fact my hot water heater is in the attic and the Hot Water Lobster is on the main floor. From what i understand, it's the thermal convection (the heated water molecules that expand to create a higher pressure on the hot water side of the plumbing system) that circulates the water through the system. I wish all products could be as simple and work so well...just my thoughts.

I certainly hope you are not a licensed plumbing contractor and do work like this. The pump system is fine. The install job. Definitely a handyman grade job. Plus, set your timer to come on at 6:00am turn off at 6:15. The hot water will get to your furthest fixture in less than 15 minutes . Then you will be using the hot water. No need to run the pump anymore at the time period. Next time. Try mounting the pump on the wall first. Then run your lines. You can lay them out much neater. Not all twisted up & taking up the lady of the house cabinet space.

Hard to believe I'm the first commenter...I'm new to all this re-cir pump stuff but after buying and refurb/remodeling my mobile home and final resting place I decided to try this system for my kitchen sink...which is way on the other end of my place. So I found one of these units on Ebay and installed it. For me the install was a piece of cake, but I'm very mechanically inclined. I only needed one medium crescent wrench... Done! Beware...the two main fittings in and out of the pump use a "ONE" way valve. Once installed I had questions so I contacted the tech service hot line provided with the literature. I was amazed at how quite this unit is...as the tech guy said... these pumps are quiet and some are very quiet. My other concern was that the motor/cartridge housing get fairly hot. The Tech guy confirmed that yes it does...when the pump is operating. After 24hrs this has been confirmed. OKAY...now here's the rub. Instant "HOT" water? Not gonna happen. Hot water within a minute is acceptable. Now for the rub...The way this works is that it keeps the hot water circulating thru your water system...hot side to cold side constantly, or should I say warm side when not in use. The pump thermo sensor controls this. BUT...on the flip side...if you want "COLD" water it take as much or more time for that to happen...hence the rub or trade off. So for me...instead of waiting "Literally" 2 minutes for warm to hot water...I get "warm" water pretty much at the hit, and the hot within a minute...which is much better than my original system. So... okay...it does a pretty good job. Now the final test will just be time & reliability. I did a LOT of research and shopping around...and some of these pumps are ridiculously expensive! This original post was from an Eastman Nevercold 70601 under sink unit video. I do a lot of business with Amazon and the Eastman water heater top mount unit on Amazon is under $300 bucks. But essentially the same unit under sink mount is over $500 bucks! I don't get that. If anything it should be the same or less and they would sell a ton of these under sink units. They are really easy to install. So there's my take...worth a couple hundred bucks...and I'm reasonably satisfied...and that's no easy task.

Very good instruction. Can you install two recirculating pumps? I've already got one installed on the water heater. I would like to know if I can install an additional one like the way you did below the sink.

How quiet does the pump runs? You should let the pump runs in this video

What am I missing or complicating? Unless you have additional return hose to main hot water system I dont understand how this would actually work.

It's simple physics that enables thermal convection to recirculate the hot water (higher presure hot water vs. lower presure cold water. Ahy way, I'm extremely happy with my Hot Water Lobster. I had a pump system in my last house that filled the entire cold water pipes with boiling hot water for the entire time the pump was running...it was impossible to get water cool enough to shower in...and the pump only lasted 2-years before failing. For this reason I would never recomend a pump system.

You did not explain how the pump works, why are you involving the cold water supply. Explaination please

Currently I have a basic duplex outlet installed under my kitchen sink but both outlets are occupied by the plugs for the dishwasher & disposal. Is it okay to install another duplex piggybacked off of the existing one?

great video,I'm trying to save water bring that its become expensive to use.I have" no water tank so what type of pump would be best for this type of situation

this is cheap and virtually useless alternative to correct installation of a "hot water secondary circulation " pump , as other posters have already stated , heating the cold water side of your system is just as wasteful , you need to dump hot water down the drain when wanting cold water plus there are serious issues to consider re' contamination of the cold water drinking supply. the only to achieve instant hot water at the taps is to run a large bore pipe ( 28mm or minimum 22mm from the top of the cylinder in a continuous loop around the property and back into the bottom of the cylinder , attach a bronze DHW pump to that pipe and you now have a safe and efficient way to achieve instant hot water from a tank fed system.

Hi loved the video - I am not handy. I live in San Diego too. Are issue is we have a Tankless water heater on the opposite end of the house that always makes it cold during winter waiting for the warm up. Last year we had a slab leak and our pipes are in the attic. So the cold is even worse. Does this video work similar with a rinnei tankless? The odd part during the repipe our plummer brought it up but with our limited knowledge we did not want to spend more money. Is it something your plumbing company can do?

Is there a way to have a recirculation pump close to the source (tankless water heater) that is initiated manually (wireless remote), but at the fixture furthest from the source, an unpowered bypass valve? There are no recirculation loops in this house either. I have seen something on Amazon.com, for a bypass valve by Grundflous, but nothing else. We do not want the recirculation pump at the furthest fixture because it is a pedestal sink. Great video.

how noisy is the pump? maybe that's a good reason to put it outside?

Thermal expansion, yeah probably. A T & P valve should be in order near the top of the piping system in the "collector" and a needle valve up there to release trapped air and back venting draining.... Mr. Greg, what kind of timer can I use for the shorter 2 or 3 minute on/off intervals? Any suggestion of brand name for me to search? Need something that will last for more than just a few months...

I would prefer to have a switch to control when the pump starts and stops. Is there one like that? Or just set to run continously and wire through a switch?

If I understand the mechanics correctly, without a dedicated return line, when the water recirculates back through the cold line, we are then drinking water that has been run through the hot water tank? I have always understood that due the use of decaying aluminum anode rods, water from the hot water tank should not be used for drinking or cooking. Is this safe?

Hi Greg. I installed the Liang pump upstairs under my sink. I run the pump before taking a shower to save water. Problem. The water seems to be lukewarm during the shower whether the pump is on or off. I assume it is cylcled off since above 100 degrees it shuts off anyway. The shower is after the sink and I assume the cold somehow is leaking into the line through the valve. As a test I shut off both hot and cold to the pump/sink isolating the pump. Water is very hot but now I'm wasting water. Any tips, differnt kind of valve?

Thanks for reply, The pressure of the water comes out of the wall under the sink (warm&cold) is too low (approximately 1 bar). I want to increase/boost it to 3 bar. It has to start when i open the faucet and stop when close the faucet. The price musn't exceed $130,- And must be small as possible. I haven't more place than what you have in the video and live in Turkey. So the wall outlet is 220 V AC. Thank you for your help.

Furthest is in bathroom, will this help when I turn on shower, if its connected under sink or should I cut a hole in wall to get to shower and fenagle it that way?? Am thinking, looks easy is a lot of moola and gas and hours of doing it..like so many of my 30 minute jobbers lasting hours or days...

So if I have one bathroom on a loop and the sink is before the shower, but obviously I want to install the bypass under the sink b/c it is accessible. The only negative is that there will be instant hot water at the sink (when the pump is on) and a couple second delay at the shower b/c it is a few feet down the line? Is this correct?

Instead of the goal to have immediate hot water.....can you rig the system to prevent water line freezing of the home's lines?

At 9:02 of the video, you mention that it will thermostatically run when it needs to keep the pipe warm, and turn off when it is warm enough. Is the user able to set that temperature? Are all these recirculating pumps thermostatically controlled? The Grundfos UP models have a thermostatic valve for under the sink, so will that pump then keep trying to run until the valve opens up again? Your video is helpful because I have wanted to install the pump under the sink, so thank you.

Hot water pipes under slab with no insulation conserve water but waste a stunning amount energy as water cools in the subsoil underneath your slab. My hot water heater would hold hot water for 2-3 days if not used but if I run the pump for 3-4 hours/day say 5-7pm then 9-11pm the hot water will be stone cold if hot water heater is not energized after the pump has run through its cycles. Best case is take a shower when pump has delivered hot water to the plumbing to be used, then de-energize the pump and hot water heater for max conservation.