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Thread: Tankless water heater, recirculation pump?

  1. #1
    DIY Senior Member Homeownerinburb's Avatar
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    Jan 2012
    Los Angeles, CA USA

    Default Tankless water heater, recirculation pump?

    Hey guys.

    My neighbor got talked into replacing his big tank water heater with a tankless. Now he is unhappy with the lack of hot water in his master bedroom shower, which is as far from the tank as any other hot water tap. Strangely, the bathroom that is adjacent to it has no issues.

    I was wondering if there is a recirculation pump that could be installed, that with the push of a switch, would push the cold water back to the tankless and draw hot until the temp rises enough.

    Here is the thing. His bathrooms are just lousy with tile, and there is no cutting of walls. The house is on a slab and the supply is in the attic.

    Is it a violation to put the pump in the attic above his shower? I know there is an electrical junction box up there with ample ampacity to drive a pump.

    If anyone could point me to a particular pump or three, I'd certainly appreciate it.

  2. #2
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Cave Creek, Arizona


    The pump that would work with his system will require a return line to the water heater. THe pump also has to create enough flow that it will turn on the gas burner. Without the heater's specifications, we could not suggest a pump that will do it. As far as the lack of hot water, that should have nothing to do with the tankless heater if it did not occur with the original one, unless it had a recirculation system and it was discontinued.
    Last edited by hj; 03-26-2012 at 06:04 AM.
    Licensed residential and commercial plumber

  3. #3
    DIY Junior Member michielsemma's Avatar
    Join Date
    Mar 2012


    Your right the navian has a circ pump build into the machine, I am a takagi rep you need a 26-99 grundfus or a 00-9 if you didnt have the pump already in the sytem. What you really want and it makes sence as a long term goal is have a takagi unit. I will assume your going to have at least 2 units to keep up with the use of water. having he demand system from taco. Look atthe taco-hvac website. going tankles and with the deman d system is a big purchase but you will be happy in the long run....
    the demand system is a button or motion detecter on a wireless remote. You only push the button as you need the hot water circulated. so it only usedas you need it. which is an estimate of 15 to 25 minutes of recirluation at a time.
    or get a high eff water heater by a. o. smith with the demand system which willalso be great.

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