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hot water recirculation pump install

3railguy Member Posts: 1
I am in the process of adding return lines from hot water taps/showers and installing a Grundfos UP10-16BN5ATLC pump, to reduce wasted water. I am unable to remove the drain tap at the bottom of the hot water tank and am afraid of breaking it off in the process. It is nylon and seized tight.  I am hoping I can T into the cold water supply line at the top of the tank and install the pump there.  I understand i will need a check valve below the pump as well as in the cold water supply side.  Will this work or am I missing something here?  Hoping to not have to buy an new hot water tank. Thank you.


  • bob eck
    bob eck Member Posts: 930
    recirculation pump

    should work with check valves in the right place.
  • EddieG
    EddieG Member Posts: 150

    The check valves would work. But I would drain it down, cut that bad valve out and re-pipe with some domestic rated piping. That valve is going to cause you problems down the road. I use a 3/4 brass nipple with a full port ball valve. Works nice to flush the water heater out.
  • icesailor
    icesailor Member Posts: 7,265
    Plastic WH drains:

    They're not all that difficult to get out if they break off. I cut them out regularly. Once or twice a year. Here's How:

    Drain the tank. Aggressively unscrew the valve, Replace it with a brass nipple, etc. If the valve breaks off, the closer to the tank, the better.

    Take a new hack saw blade or a recip saw blade in a holder. I like 14 tooth blades. Carefully cot a slot through the plastic nipple and try to stop at the top of the threads. Cut at 6 O'clock, 7 O'clock and 3 O'clock. These two cuts should be closer together and it is best that a part sticks past the opening. Take a sharp heavy screwdriver and place it next to the tank and on the nipple. Hit it with a good heavy hammer. The piece should drop out. If it doesn't on the second whack, cut it some more with the blade. Once you knock it out, the small piece, remove it with a pair of needle nosed pliers. Hit the remaining nipple so that it splits on the other cut. Once they come together, take the needle nosed pliers and unscrew the remains.

    Do not worry if you damage the end of the threads. Put at least three wraps of Teflon tape on the new threads and use some pipe lubricant like MegLock or Rectorseal #5. Crank it in.

    I have NEVER had a connection leak,
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