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Under sink recirculation

Intplm.Intplm. Member Posts: 1,186
These under sink recirculation valves that have been gaining in popularity over the past years are great for residential use.
Watts calls there valve the "Premier". Grundfos has one called the "Comfort valve". Other manufacturers I am sure are out there.
My questions: What's the difference between these two valves? And for that matter, what's the difference between any of these valves that are made to do the same thing?
I have had many opinions expressed toward me saying that one is better than the other. Also have gotten the speech that if you use one with a pump that is not watts or grundfos, (interchanging the valves) that the warranty can be void??
I can't identify any differences in the valves.
Has anyone out there experienced this? and if so, how did you resolve the issue?
Thank you ahead of time for your input.


  • Larry WeingartenLarry Weingarten Member Posts: 1,911
    Hello, This isn't a direct answer to your question, but you might want to have a look at It's a slightly different technology that works with less energy loss than other approaches.
    Yours, Larry
  • Intplm.Intplm. Member Posts: 1,186
    Thanks Larry. Never heard of that one. Looks like a great alternative to what I'm asking about. I hope others will offer there input.
  • JUGHNEJUGHNE Member Posts: 7,182
    Is your basement ceiling open and accessible to the sink you are considering for recir.
  • Intplm.Intplm. Member Posts: 1,186
    Hi JUGHE. It is but not a concern at this time. Im looking for info on the difference between the two, and any others that exist out there.
    The valves seem to be all the same with the only difference being the name embossed on the valve itself. I'm hoping that someone out there can verify that these valves are the same. Having some difficulty getting verification.
  • JUGHNEJUGHNE Member Posts: 7,182
    What has existed for many years is natural gravity recirculation.
    I have the farthest bath 60 pipe feet from my WH. A 1/2" return line connected to the bottom of the WH gives me 2 seconds or less to hot water at that distance. And everywhere in between.
    No moving parts, pumps or electricity needed. Nothing to fail.
    Pipe and fittings only....will work indefinitely.

    Details if you want them.
    rick in AlaskaIntplm.
  • delta Tdelta T Member Posts: 814
    What JUGHNE was hinting at I think is that if it is feasible to run a dedicated recirc line, that is ALWAYS better. Any type of under sink recirc system will create a cross connection between the hot and cold water lines. I have lots of problems and complaints with all of the undersink style recirc systems, and I no longer install them.

    That being said, to answer your questions, the watts Premier valve is exactly the same as the grundfos comfort valve. Grundfos manufactures them for Watts.

    If you look closely at a picture on the watts, you can see in the casting it actually says 'manufactured by Grundfos'

    I can't imagine there being a problem with using one's pump with the other for warranty claims.

    My personal preference is the grundfos comfort pump, with the sensor on a dedicated recirc line. The auto adapt feature works very well and I have had no complaints.
  • JUGHNEJUGHNE Member Posts: 7,182
    The materials for my own system cost less than half of any brass or SS pump and aquastat.
  • Intplm.Intplm. Member Posts: 1,186
    Thank you delta T. I haven't seen that. I've been turning pipe wrenches for better then 40 yrs now and I guess I can't see that small writing any longer.(" Reading glasses #275. Being allowed to have lasik. Priceless.")
    My preference has been the grundfos with dedicated recirculation line as well. Haven't had the amount of complaints that you have had but yes, cross connections between hot and cold have to be something our customers can tolerate. My experience has been that customers, when warned in writing that there will be some hot at first use in the cold, will commonly be acceptable.

    Thank you all for helping. Very appreciated.
    delta T
  • Intplm.Intplm. Member Posts: 1,186
    JUGHNE....Please do offer those details. I like the thought of what you are referring to.
  • JUGHNEJUGHNE Member Posts: 7,182
    Under the master bath lav, (farthest fixture) I added a tee/ball valve to the hot riser as high as possible as these lines come thru the floor.
    From there 1/2" copper was run back to the WH drain valve.
    I was able to provide slope on the recir line all the way back.
    What is important is to not have any air pockets in place...that is you can not jump over a beam and then back down....might not flow.
    At the WH drain a tee was added, another service ball for flow adjustment. Then a swing check valve to prevent cold coming from the water heater going up into the recir line.
    I might have 24" of vertical drop at the lav and 7' of vertical drop at the WH. In between on the horizonal run there might be 15" drop.
    The difference in temp and gravity induces the flow.
    It is all insulated with 1/2" foam or FG. 1" would be better with less heat loss as this is a constant heating circuit.
    The vertical drop at the WH is purposely not insulated to cool the water inducing the flow.
    If there is lack of adequate flow then an 1/8" hole may be drilled in the swing flapper of the check valve. I did not have to do that.

    Most of the run is 1/2" ID copper, I had 30' of 3/8" ID to get rid of so used it to start from the bath. All is hard rigid copper.

    Some will claim that it is wasteful to have constant gravity circulation. But probably the 74 temp in the bathroom is also that. :)

    But for the money saved in pump, control, power and replacing the pump in the future I am ahead.

    Remember all the water run down the drain waiting for hot to arrive was at one time heated to be hot water.
    delta TSuperJ
  • delta Tdelta T Member Posts: 814

    Here is a good pic of one where you can see the 'manufactured by Grundfos'.

    I ran into the problem for so long of trying to explain to people that they would get hot water out of the cold side, but they would be so caught up in the 'I must save money, I must be green' mindset that it seemed to go over their heads. Until afterwords and then I get the call "why is there hot water coming out of the cold side of my faucet? I think that thing must be deffective...."

    I just gave up. I no longer live in the same town, and it would likely be fine to start using them where I am at now.

    Boulder was a special place.....

    I like JUGHNE's gravity recirc line! I might try that at my house when I finally get around to renovating the place....
  • JUGHNEJUGHNE Member Posts: 7,182
    edited December 2018
    This is the article I found years ago for this recirc system.

    If I am gone for a week or more I might shut off the return valve at the water heater......that makes me feel "green"

    Maybe this article should be in the wall library.
  • SuperJSuperJ Member Posts: 586
    JUGHNE said:

    This is the article I found years ago for this recirc system.

    If I am gone for a week or more I might shut off the return valve at the water heater......that makes me feel "green"

    Maybe this article should be in the wall library.

    I'm going to try this in the next couple weeks, was going to add a recirc pump, but I will try this first since I'll be adding a return line anyways. Was thinking of doing it all in pex. My only concern is I have a mixing valve on the discharge with inlet check valves, that might be enough to break the thermosiphon.
  • JUGHNEJUGHNE Member Posts: 7,182
    I thought about PEX also, but considered it might get too wavy for maintaining slope, which may or may not be that critical.
    But I was finishing the ceiling and wanted to be as sure as I could to take advantage of establishing slope. From just looking at old gravity heating systems they made certain of it.

    Also if you took the return into the tank itself would that cause the hot to flow into the mix valve and thru your supply?
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