How to Install a Hot Water Recirculation Pump (Part 2: Sensor Valve) 

Very good point.. everyone in freezing zones knows to leave their water faucets open just a few drips in order to keep the pipes from freezing... but this system might warm all the lines w/o constant monitoring.

Exact idea I had.

Did this work out for you? I was considering the pump for this same application. But I’m curious if the sensor valve will stop the water from dumping to the cold line after it reaches a certain temperature.

Thanks

If your building a new house you have all those options.. yes smaller return lines directly to the tank keeps your cold faucet cold. Don't forget your external holiday outlets, under cabinet lighting, exhaust fans in every restroom, 220v in the garage + extra lighting and tons of outlets.. the list goes on and on.. but it's the small stuff like these that make a huge difference later. Extra gas lines and electrical to the backyard.. maybe even a sewage line.. cap them off for now... but you'll be glad you laid those some day.

The recirculating function means that the hot water leaving your tank passes by the hot water faucet and is pushed back along the cold line when not in demand. The hot water recirculates to the heater. Now if you installed the pump on the wrong side of your water heater................

Make sure the valve is installed with the "correct" side facing you. If you did it the other way around, you then inadvertantly piped it up backwards. Something to check. Otherwise.....these things are known to fail or even be bad as received on occasion. Might be a bad unit. Seems only one company makes them... Grundfos/Watts.

Yes, being in a series then install on the second as this one will draw the water through the first heater as well

Totally false, at least with this product. You can't hear it at all unless you're 1 foot away.

Yeah, my water heater doesn't get enough credit for the tireless work it does, either. I should really treat it to a spa day or something.

Isn't that just how it's supposed to work? Some of the hot water is sent via the cold water line to the water heater and back through the hot line. Naturally, the cold water line will be lukewarm for a little while until it equalizes to room temperature or is purged with fresh cold water. If you don't want to have to deal with that, you'll have to plumb a dedicated return line back to the water heater.

Kay, I'm just stopping by and want to help out. I got the same situation and I installed it under the sink and it would work beautifully. My shower has hot water immediately after the pump stop. It is because the pump push the water back to the tank so that there is only water (hot but cool down) in the section of the shower will be wasted instead of the whole pipe system if there is no pump. Hope it helps

Yes just do the furthest sink. The shower will draw.

It is my understanding that the hot water recirculates through the pipes. When you attach the sensor to the furthest point (sink) anything in between the source and that point will benefit. The in between points are still far closer to the hot water than before.

True....unlike the old fashioned homes that have major "Trunk" lines to and from the water heater tank ( and have branch-tees from these "trunks")......they now seem to plumb individual branch lines to each use-point, often with PEX. Regardelss.....even with a STAR pattern like you describe, it will make it more difficult for ALL the water to mix. In such cases, after you install the first valve at the furthest-away sink....you may find the need to add another valve at some other part of the house. Maybe even more than 2. Trial and eror.

Randy Cruz why ?

The sensor valve has a gel tab so to speak inside, once the temp goes below a certain temp it will open up and allow the now cooled water into the cold water side, this is where your pump comes in, pumps that water through and feeds the hot water back up to that fixture... now the sensor valve detects hot water will close off and the fixture operates as it normally does

@@footlongburrito Nava: If we install the sensor valve on the cold water tap, we do not need a recirculation pump. When you open the cold tap, the cold water in the hot water pipe is purged and when the hot water arrives, the valve closes and the cold water tap is fed by the cold water pipe.

@@ajarivas72 congratulations you repeated what I already said

@@footlongburrito Hi Brandon I am a victim of the secular marxist public school system

@@footlongburrito : My scheme does not involve a recirculation pump

Unfortunately I don't know of a way to fix them, but the best price is on amazon: amzn.to/2kX4nLb

@@besthotwaterrecirculators1928 : If we install the sensor valve on the cold water tap, we do not need a recirculation pump. When you open the cold tap, the cold water in the hot water pipe is purged and when the hot water arrives, the valve closes and the cold water tap is fed by the cold water pipe.

@@ajarivas72 So you're wasting a bunch of cold water down the drain just to get your hot water line up to temperature? Isn't that exactly what you bought your recirculating system to avoid? Might as well not have that valve at all and just turn on the hot tap directly and waste the same amount of water.

yep.... don't need to drain the tank

I thought opening the faucet valve after closing the water tank inlet valve only relieved pressure. Wouldn't there still be a lot of water in the hot water pipes ready to pour out as soon as you disconnect the outlet pipe at the top of the tank? It's against code to install a valve on the hot water side of the tank to prevent such back spill. When does water flow uphill without any pressure applied?

he didn't empty the tank, he just relieved the pressure.

@@moonrich3492It flows uphill when heated.

I'm looking to install the same thing and just recently had a conversation with my plumber about it. The way understand it, is that you don't really hot water on the cold lines. A sensor valve detects the hot water pipe is no longer hot, and then it starts the pump. At that point, the cold water lines get a somewhat lukewarm water. Even with a timer schedule, it's guaranteed that the hot water line is actually cold in the morning. So when the pump starts at 7:00 AM it will actually pump cold water from the hot water line into the cold water line. You should schedule it to run when there are large gaps of times between the times you need hot water; morning and after getting home from work.

@@MrSchmuck If we install the sensor valve on the cold water tap, we do not need a recirculation pump. When you open the cold tap, the cold water in the hot water pipe is purged and when the hot water arrives, the valve closes and the cold water tap is fed by the cold water pipe. Once the valve shuts off, the hot water is just centimeters below the hot water tap.

@@ajarivas72What is the difference in doing this and just opening the hot water valve? Why would it draw hot water through a restriction rather than cold water.

@@davidstevens1911 no difference.

That was my question, too. Wouldn't it be prudent to install a check valve on the cold water intake at the water heater? Or maybe the tankless already incorporates that?

It is a closed loop system. The pressure on the inlet of the HW tank is going to be relieved by the water being drawn from the outlet of the tank. The water pressure at the outlet of the pump is going to be city water pressure plus pump pressure. The pressure at the inlet of the pump is going to be city water pressure minus pump suction pressure. IWater does not compress. Most modern hot water tanks have built in check valves (probably not the right name) or they are added. Their purpose is to keep the hot water in the tank. Without them the hot water in the tank rises to the top and continues up the cold water line where it cools and falls back into the tank. If water could be pushed back into the city water system you can be sure the plumbing code would require a backflow preventer.

use two .

UHENIO ALVAREZ k

Yes, connect the two hot water output sides into one using a "T" and install the watts 500800 at the very end of the new combined hot water feed. use shutoff ball valves before each hot water connection to isolate each tank for future service, you may have existing valves you can use those.

You must have a lot of space under your sink to spare for that bulky item?

@@worldview730I do.

Hook it to either one, preferably the one that's slightly farther away from the water tank. It won't make much difference.

@@moonrich3492 If we install the sensor valve on the cold water tap, we do not need a recirculation pump. When you open the cold tap, the cold water in the hot water pipe is purged and when the hot water arrives, the valve closes and the cold water tap is fed by the cold water pipe. Once the valve shuts off, the hot water is just centimeters below the hot water tap.

I think it won't change your bill since the heat from the pipes will offset heating your house.

Michael Gerhart I think you don’t use thread tape because the is a sealing washer involved (like a garden hose). The threads do not do the sealing, the washer does.

Right, he just needed to tighten it a little more. It's best not to overtighten.

No need on compression fittings.

No, there is no hot water in the line when you use a tankless water heater. There is no hot water in the line anyway but if you use this pump there will be. Do not use for a tankless water heater.

Rinnai has models that have internal circ pumps. Wifi controller too.

@@jeffstanley4593 Jeff If we install the sensor valve on the cold water tap, we do not need a recirculation pump. When you open the cold tap, the cold water in the hot water pipe is purged and when the hot water arrives, the valve closes and the cold water tap is fed by the cold water pipe. Once the valve shuts off, the hot water is just centimeters below the hot water tap.