Another question on recirculating pump - how to connect to water heater?

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by CountryBumkin, May 11, 2013.

  1. CountryBumkin

    CountryBumkin New Member

    Messages:
    86
    Location:
    Orlando, FL
    recirc plan 2.jpg Recirc pump install diagram.jpg I have been waiting for the day when my 20-year old water heater needed replacement to take my house plumbing project to the next step. That day has come. I just bought a new electric water heater and now I am in the process of collecting all the parts I will need to self install. I want to install a recirculating pump for the master bathroom show at the far end of the house. I already have a Grundfos "Comfort Pump model UP10-16BN5/ATLC". I am using PEX (Uponor's AquaPex) throughout.

    Here's my plan: The master bath is at the far end of the house (single story, Ranch style in central FL). I have already refinished/replumbed the master bath with PEX and I have the water supply feed in the attic. Background: Currently the water comes out of the slab in PB hose then I converted that to PEX that runs up the interior wall into attic and then back down to shower fixture (the idea being if the PB fails I can abandon it in the wall and make my new water feed connections in the attic.

    Now that I am replacing the water heater this is the time to do step two of my plumbing plan (add the recirculation pump). I will cap off the shower water feed from the PB and re-feed the shower fixture with a new run of (1/2" insulated) PEX through the attic from the water heater (coming off my (yet to be purchased) "PEX Aquacenter" manifold and then add the recirculation pump to one of the hot water feeds off the manifold).

    My questions are: From previous posts here, I know that it is desirable to have the recirculation return line go to the bottom of the water heater.
    1) Should I remove the existing tank drain valve (I assume its threaded into the tank somehow) and install a tee (one side of the tee being the return line, the other for the drain valve) - or
    2) should just connect directly to the brass drain fitting on the water heater (the drain has a threaded "hose" connection for draining. But this sloppy in my mind) - or
    3) would it be better to just install the return line at the cold water inlet at top of the tank?

    What do the professionals do? The water heater is a Rheem Fury 83VR66-2.


    I'll draw up a sketch of my plan, and post back shortly, to help you visualize what I'm thinking of doing. Thanks in advance for your replies/help.
    Last edited: May 11, 2013
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,997
    Location:
    New England
    Do not put the pump IN the supply line...put it on the return line, otherwise, all of the water must pass through the pump, and that may not work well. I'd probably replace the (generally cheap plastic) drain valve on the bottom of the tank with a nice ball valve, and plumb in a T fitting to return the water to the tank through that. The ball valve will give you a straight shot you can eventually try to crack up any mineral deposits that accumulate in the bottom of the tank, and, being a full-port ball valve, will provide better flow should you decide you want to flush it on occasion. I'd also consider adding another return line or two, so all of the fixtures would get hot. You can control the pump with a timer, a demand switch, an occupancy switch, or just let it run.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,626
    Location:
    Cave Creek, Arizona
    That pump is NOT the "Comfort one that works with the "comfort valves". It should be in the "return line" just before it connects back to the heater. IF you do use the "Comfort" system. That pump attaches to the hot water outlet on the heater and the valve goes in the supply line to a sink faucet, NOT the shower or tub valve.
  4. CountryBumkin

    CountryBumkin New Member

    Messages:
    86
    Location:
    Orlando, FL
    Thank you for setting me right. I will use "plan 3" based on your advise and put the pump in the return line near where it connects to the drain fitting. Should I still use the check valve between the pump and the drain line (or somewhere else in the system)?
    The Grundfos pump I have (not called the Comfort System) has a timer in the head and a rotatable knob on the side for temp control. I will mount this low near the water heater and have it pump in the direction of the water heater.
    Thank you again for the help you provide.

    Attached Files:

  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,626
    Location:
    Cave Creek, Arizona
    Pump, check valve, control valve, connection to heater, in that order. The temperature control will be basically useless. It will shut off when the temperature is reached AT THE HEATER, but that will have absolutely no relationship to what the temperature is at the faucet where you want the "instantaneous" hot water, when the pump is not running and cooling takes place.
  6. CountryBumkin

    CountryBumkin New Member

    Messages:
    86
    Location:
    Orlando, FL
    I see your point. Darn. So this won't work unless the pump is mounted at the shower area near the "Tee" fitting - since the temp control is built into the pump. I suppose I could mount the pump in the attic near the return line T.
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