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domestic hot water recirculation

bob eckbob eck Member Posts: 560
when the customer complained that it took to long to get cold water at her kitchen sink how long were you running the pump. were you using the timer or just letting the pump run 24/7?


  • bob eckbob eck Member Posts: 560
    domestic hot water recirculation

    Is anyone currently using the grundfos comfort pump with comfort valve system for domestic hot water recirculation? or do you use their pump that you have to run a return line back to the water heater? do your customers like these systems? any trouble with them?
  • schillerschiller Member Posts: 60

    we have been using it for about 3 years as a add on or up sell. the only issue we've had was a customer wanted it for faster hot water at the kitchen sink. well the next day she called back and complained that now it took to long for her cold water to fill the dog's drinking dish and it made her arm sore!! (some time's customers leave me speachless) any way now I ensure that I tell people the the cold line is used to return the water to the tank and it will take a few minutes for the cold to get there. its a great product to carry as an add on or up sell
  • BrianBrian Member Posts: 115

    If you can, run a seperate return line back to the heater. I use a grundfos pump with built in timer and aquastat. I let the pump run 24/7 and let the aquastat control the pump. Unless you have a very strict time frame of water usage timers kind of defeat the purpose of having instant hot water.
  • ALHALH Member Posts: 1,790

    Occupancy sensors are ideal if possible, although they are probably not an easy retrofit option.
  • jpjp Member Posts: 1,935
    Hmmm Andrew

    thats a good one, been thinking of a more intelligent solution for cycling water. best I've come up with is a demand switch, I like your idea better.
  • GMcDGMcD Member Posts: 477
    A tip with low flow fixtures and faucets

    One of the things I've learned over the past few years with low-flow faucets now being mainstream, is that hot water recirc or electrical heat maintenance cables need to be taken to within 6 feet (or closer) of the faucet to reduce the "run-time" to get hot water at the tap. If you add up all the wasted expensive treated drinking water that goes directly to the drain while folks run the taps to get hot water, it would make your head spin.

    What's the use of a low flow faucet if they end up running more water over time to get the hot water there in the first place? It's a bit more first cost to run recirc piping or heat trace cable closer to the taps, but it sure saves a ton of water over time. Even in residential houses, you guys ARE insulating the domestic water piping, right?
  • Larry WeingartenLarry Weingarten Member Posts: 1,173
    As an option...

    ...have a look at

    Yours, Larry
  • Chris SChris S Member Posts: 177
    motion sensor

    Wirsbo offers a motion sensor for that purpose- it's a little unsightly for a high end bath in my opinion. Any alarm installer could make that connection in a retrofit, they're used to challenges

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  • jpjp Member Posts: 1,935
    hide it

    you can almost hide the sensor, only needs to 'see' the feet entering the bath. alarm sensor sounds interesting also.
  • TimTim Member Posts: 9
    Grunfos & Honywell mixing valve

    I use a grunfos uP15 with a timer. I run my hot water at 140F. I mix it to 120 and all is well except when the recirc pump runs. The temp goes to 140F in the line until a faucet is cracked and then the cold water tempers it.
    I have tried aquastats and they still do not help the problem. Has anyone else run into this situation and cured it? I think if I used the grunfos up10 with an integral adjustable aquasta it would help but not cure the problem. I have noticed Armstrong make units with digital controls.
    I have no experience with them.
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