1. plumberwanabe

    plumberwanabe New Member

    Messages:
    6
    Location:
    Bellevue WA.
    I'm interested in installing a hot water recirculation system, with a dedicated return line. The dedicated return line will be made of 1/2" pex. What should I look for in a pump? Should I make the return line enter the hot water tank at the cold supply side with a check valve? Or is there a better design for the return water? The system will have 5 or 6 feet of head. What's a good brand name of pump?
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,486
    Location:
    Cave Creek, Arizona
    Regardless of where you connect it back, cold water inlet or drain valve, it MUST have a check valve. Almost any pump is adequate since the only "head" will be caused by the water's velocity, but you want the water to flow as slowly as possible and still maintain the temperature.
  3. Terry

    Terry Administrator Staff Member

    Messages:
    14,889
    Location:
    Bothell, Washington
    Grundfos makes a nice pump, and also an optional "clip on" that shuts the pump off when the return comes back warm. It keeps the pump from running non-stop.

    I like to pull and extend the water heater drain and run the recirc in there. I use a spring check.

    I wound up parking at city hall Wednesday while Jamie was playing Bellevue City Center.

    [​IMG]
    Last edited: Sep 14, 2013
  4. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,328
    Location:
    Yakima WA
    Here's how my system is plumbed. Not the only way, but it's worked well for me for about 8 years. The return line reached the area of the tank at just a bit above floor level. The first fitting is a ball valve. Then the line runs into the Laing pump. After the pump, there is a tee. One side of the tee goes to the floor drain, the other directs the pipe up to just above the top of the tank. Now the pipe elbows toward the tank and through a check valve. Following the check valve, there is an air vent. Another ball valve follows the air vent and then the pipe is teed into the incoming cold water pipe. I elected not to have a timer, but that is an option many people prefer. I use all copper and the hot water lines, including the return line, are insulated. I'm not a fan of PEX, but it would probably work just fine.
  5. Hairyhosebib

    Hairyhosebib New Member

    Messages:
    173
    Location:
    Arizona
    A check valve is needed but get one used in the solar hot water industry. One that may only need a half pound of pressure to open it. You can get a Grundfos circ pump that may only be 1/64 of a HP. That be just about nothing in electrical use. It just keeps the water moving. I would extend the drain and make the tie in at the bottom of the tank. Hopefully your tank is not full up to that point of accumulation of crap. If you have filtration and a condition system of some kind it should be good for a long time. Otherwise junk might build up in the check valve and it will drive you nuts that it does not work very long.
  6. plumberwanabe

    plumberwanabe New Member

    Messages:
    6
    Location:
    Bellevue WA.
    Thanks for the feed back!
Similar Threads: recirc system
Forum Title Date
Plumbing Forum, Professional & DIY Advice, Tips & Recirculating Hot Water System - Duty Cycle Options Apr 22, 2014
Plumbing Forum, Professional & DIY Advice, Tips & Basic system with recirculation anything else needed? Apr 7, 2012
Plumbing Forum, Professional & DIY Advice, Tips & Water recirculation system Apr 7, 2012
Plumbing Forum, Professional & DIY Advice, Tips & recirculation system issues....Too much of a good thing Feb 3, 2012
Plumbing Forum, Professional & DIY Advice, Tips & Multi-branch recirculation system Oct 18, 2010

Share This Page