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Thread: GRUNDFOS recirculating installation?

  1. #1
    DIY Junior Member Handiman's Avatar
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    Question GRUNDFOS recirculating installation?

    Just got a new water heater and the plumber insisted that all recirculating pumps should now be installed to recirculate hot water down at the drain valve instead of on top of the water heater. Is this the best place for the GRUNDFOS, b/c I think their website says to install at the top of the water heater.

    BTW it is a 20+ year old GRUNDFOS UP15-18SU and was wondering what the lifespan of these things are? I don't have a timer on it so it runs constantly. Now debating if I should just invest in a new pump or add a timer to this existing one. Plumber installed shutoff valves on both sides of the pump.

  2. #2
    Plumber jimbo's Avatar
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    Quote Originally Posted by Handiman View Post
    BTW it is a 20+ year old GRUNDFOS UP15-18SU and was wondering what the lifespan of these things are?

    Less than 20 years! You are on borrowed time.

  3. #3
    Plumbing Designer FloridaOrange's Avatar
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    Quote Originally Posted by Handiman View Post
    Just got a new water heater and the plumber insisted that all recirculating pumps should now be installed to recirculate hot water down at the drain valve instead of on top of the water heater. Is this the best place for the GRUNDFOS, b/c I think their website says to install at the top of the water heater.

    BTW it is a 20+ year old GRUNDFOS UP15-18SU and was wondering what the lifespan of these things are? I don't have a timer on it so it runs constantly. Now debating if I should just invest in a new pump or add a timer to this existing one. Plumber installed shutoff valves on both sides of the pump.
    Most manufacturer recommendations I've seen tie it into the bottom of the water heater, I've also designed quite a few that tie into the cold water line supplying the heater.

    As mentioned above 20 years is awesome, you must have really good clean water. While you're at it with the timer you might want to pick up an aquastat, no sense circulating water that may be maintaining temp.
    Matt
    Semi-professional plumbing designer
    Enjoying life in SW Florida

  4. #4
    Moderator & Master Plumber hj's Avatar
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    Default pump

    The connection to the water heater can be at either location. The pump should always have had both valves and a check valve. Use a timer and close the valve BETWEEN the pump and the heater until it just maintains the temperature of the returning water. This will maintain the water temperature, save energy, and reduce erosion wear on the water lines.

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