3/4 Inch Hot Water Circulating Pump 3-Speed Circulation Water Pump for Solar Heater System(RS15-6 Red)

I use this as a hot water recirculating pump. It works great. Developed a click after a while but pump kept working long after.

Recirculating hot water system conversion is an upgrade that everyone should add to their house and this is a bargain way to do it. Instead of waiting for an eternity for a warm shower, supplying dishwasher or washing machine with minutes of cold water before the hot water arrives, this provides instant hot water. Just do it.

TLDR: The non-stainless version WILL rust; try different versions (and different "brands") of this pump if yours doesn't seem to pump enough water; ensure your pump comes with the pipe fitting adapters (that have o-rings) because the threads are NOT true NPT-fit threads and will leak; instructions are a joke so read enough reviews/do your own research to make sure you know how to install this (it's not complicated but the instructions make you question your own intelligence); no "on/off" switch so plan to use with a switched outlet or smart outlet for control.This review is for the unit I bought (RS15-6 Blue). I intended to use it with the Grundfos-made thermal bypass valve for creating a water recirculation circuit for my tankless water heater system. I saw several reviews that said this worked for people, but it was not always clear whether they had a tankless system or not. Tankless water heaters require a minimum amount of water flow to turn on (typically ~0.5gpm) and after plumbing this pump and the bypass valve, I discovered that I would only get about 0.3gpm through my water heater. I tried all the power settings on the pump, "bleeding" the air with the screw on the front and flushing the lines, nothing helped. "Bleeding" with the air screw did let out some spits of air/water but the way the o-ring seal is designed, there is no way to get it to seal again while the pump is running so beware of doing that and/or be prepared to get wet. I "knew" that the fittings were 3/4" MIP so I also bought all the associated hardware to plumb this into the existing copper hardline on the INLET to my heater (used SharkBite fittings + 3/4" coupling to a 3/4" nipple so that I could have something rigid to use for mounting with 3/4" pipe clamps). The installation was fine except that even with a more-than-typical amount of teflon tape, I was not able to get a leak-free connection between the coupling and the pump. I made the connections quite tight and I was worried I would over-tighten and crack something. I did make a simple plywood base to allow the flat sections of the pump to rest since my pipe situation would not support the pump on its own.Since the pump did turn on and wasn't overheating or making any weird noises (it was very quiet actually), I assumed that I was just out of luck since the Grundfos valve kit I purchased actually did explicitly state that it was not for use with tankless water heaters (though it said the reason was that it was not designed to be used with systems that had a water-return circuit). After a couple of days I uninstalled the pump again to see if I could figure out if there was something mechanically wrong, and that is when I saw the RUST in the pump. I was very disappointed to see that and also very upset that I potentially put my family at risk for having that in our drinking water system. I also read someone else's review about making their own parallel valve circuit with two Grundfos valves and additional hoses/fittings to allow twice the flow through the valves. So in a second round of attempting to get functioning water circulation, I bought all the pieces needed for making the parallel valve setup AND a stainless-steel version of this pump, but under a different name brand (BokyWok).Once I received the new parts, I first decided to just install the new pump and see if that would make any difference. I was surprised to find that there was actually an adapter in the kit that would connect to the pump with a 3/4" female O-RING fitting and then adapted to a true 3/4" NPT thread. I didn't end up using them, though, because I just tried to connect the SharkBite adapter hoses directly (the non-SharkBite end had a 3/4" female o-ring connector) and used some thick cardboard spacers to allow a standard 3/4" pipe clamp to secure the whole thing in place to my plywood base. After this simplified installation was done, I turned on the pump and the heater kicked on!! This was WITHOUT making any changes to the Grundfos thermal valve installation, and I was now seeing about 0.5-0.6gpm flow through the water heater.This has been installed for a couple of weeks and still working fine...returning the crappy pump I received and the now unnecessary additional thermal bypass valve components. Lots of small lessons here, but my biggest suggestion is to try at least a couple of pumps from multiple vendors if yours isn't working. I looked at many pumps and they all seem to be the exact same imported hardware with various branded stickers on them (including the "official" Grundfos ones).

Definitely a nice pump. Very quiet and seems to be plenty powerful to get the hot water circulated.As some others have mentioned, the threaded are 3/4 straight thread. All copper threaded pieces are typically tapered (NPT). The way I got around this was to use dielectric fittings with a 3/4 FIP to 3/4 sweat ends. This does two things for you. One, it gets you the straight threads to get a good seal with teflon tape. And two, it allows you to totally remove the pump without having to cut any pipe.I run the pump using a smart plug hooked to my google home. I set up a custom routine so I just have to say one word and it runs the routine of "Turn on hot water for 1 minute" where the smart plug is named "hot water".

I rated it for its quietness. But, as in all the reviews as stated, the threads are straight and not NPT. I did get them to stop leaking with 2 adapter fittings from Amazon. Brass fitting 2 pack with female 3/4" hose and male 3/4" NPT. I replaced their hard gasket with a softer hose gasket and cranked down on that fitting pretty good. Also teflon tape. I used this on my water heater in conjunction with a heavy duty programmable timer. since I'm retired, I set it for my most common times. I also liked the Smart switch idea. I would really just like to use a remote instead of an App.

I installed this recirculating pump in parallel with smart Valve on my Tankless water heater to get hot water instantly by recirculating all cold water in hot water line. It feels great to have hot water instantly when you turn the tap during winter mornings. I save around 5 gallons of water every time I need hot water and this very much required in every home in So Cal where we have drought all the time.I installed recirculating pump at the hot water outlet on tankless water connected to a smart plug and at the far end of the house I used this smart value (https://www.amazon.com/gp/product/B08Q364CCZ) to connect the hot water and cold water line. When I instruct my google home to turn on the pump it will turn on the recirculating pump which in turn will open the smart valve. There is a timer which turns off the pump after 3 mins, which will in turn shut the smart valve. Initially I placed a Grundfos 595926 Valve in place of the smart value but its working intermittently and not perfectly.This recirculating pump and smart valve is a great addition and its running with no issues for last 4 months. We turn this system 5 to 6 times every day. I strongly recommend buying a Midline Valve EVGG0034-OM Dielectric Union Pipe Fitting (https://www.amazon.com/gp/product/B08L5QTHN2) which saved a lot of time with installation.

I was having a chat with Mary Rose and got disconnected.

Good product for the money - using this pump on our water heater to circulate hot water throughout the house - all faucets have hot water at the ready and we love it - easy to install - one thing that we noticed when first installed is there was a smell that came out of the hot water but it only lasted about 2 days and no more after that - we figured that it was caused by some oil in the pump that made it's way in the hot water once installed and dissipated over time. Good product! I had a pump prior to this one that cost 3X the amount of this one and it only lasted one or two years....so this was a good choice for us.