Where to install thermal expansion tank

Discussion in 'Water Heater Forum, Tanks' started by Jsmallberries, Mar 22, 2020.

  1. Jsmallberries

    Jsmallberries Member

    Joined:
    Nov 2, 2015
    Location:
    Zephyrhills, Florida
    Have 50 gallon natural gas water heater installed in the garage.

    The old one was on an 18"stand. The new one was installed on a new stand for ease of install with existing plumbing, even though it could have been on the floor since it's a sealed combustion chamber.

    How could I fit an expansion tank here? see photo. Plumbing pipe is CPVC
     

    Attached Files:

  2. Terry

    Terry Administrator Staff Member

    Joined:
    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    I've been using these fittings in brass

    3/4 tee
    3/4 90
    3/4 x 6 nipple
    3/4 x 2 nipple

    [​IMG]

    An expansion tank anywhere on the cold side works. I have mine by the front of the garage mounted on the wall.

    [​IMG]
     
    Last edited: Mar 29, 2020
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  4. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Alternate idea:
     

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  5. Jsmallberries

    Jsmallberries Member

    Joined:
    Nov 2, 2015
    Location:
    Zephyrhills, Florida
    Thanks for the advice, and Reach4, love that alternative, as I don't have room around the WH and the entry main by the garage door opening is only a short stub out with a brass shut off, don't want to mess with it due to the fact that the builder buried the cinder block bay with mortar in this one section, right where the plumbing main comes up into the wall.

    Found this out the hard way
     

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  6. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    You want to be aware of https://terrylove.com/forums/index.php?threads/tet-deadlegs.86420

    As you can see, there is a question discussed there. I think this is not a dead end, but my opinion is not definitive.

    You can get drop ear elbows that take 1/2 inch PEX or copper, but have the 3/4 inch thread for the thermal expansion tank.
    [​IMG][​IMG]
     
    Last edited: Mar 25, 2020
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    The water will move in and out of the ET during most water heating cycles. Now, it would depend on how long you make the branch. It will not fully empty the ET during a normal cycle. You'll push more water out after emptying the tank and then not using any hot water for awhile. That will fill the ET more, and the next time you use any water (hot or cold), it will push that 'extra' back out into the supply line.
     
  8. LLigetfa

    LLigetfa DIYer, not in the trades

    Joined:
    Feb 6, 2011
    Occupation:
    Semi-Retired
    Location:
    NW Ontario, Canada
    The ET should fully empty during a normal cycle provided the precharge is higher than the water pressure is while being drawn. As to whether the entire "dead" leg contents gets purged/replaced depends on the length of the leg and the volume of water that is pushed by the expansion.
     
  9. BobbyH

    BobbyH New Member

    Joined:
    Jun 24, 2018
    Location:
    Idaho
    This is my install

    6B8B34FB-8698-4024-8B35-42C3847248E6.jpeg AF8EE6EA-F4C1-4228-90E9-78CA5A3BAB7A.jpeg
     
  10. Jsmallberries

    Jsmallberries Member

    Joined:
    Nov 2, 2015
    Location:
    Zephyrhills, Florida
    Thanks guys,

    I was able to install the tank per Terry's instructions, thought the tank was larger than it is.

    Only concern was the new copper flex supply line, had to force it into position, has a slight over bend where it connects to the supply line. Look okay to you?

    The incoming pipe is 20 year old CPVC, brittle and weak. These plastic pipe to metal transitions are supposed to be secured, but they're not, I could feel the torque as I tightened it, the concern is the pressure at the elbow below the drywall is a weak point.I was thinking of opening up the wall and re-pipe, or am I over thinking this????

    I was changing a water shutoff under the kitchen sink recently, with 2 wrenches in opposite direction as needed to reduce stress on the cpvc supply pipe and the pipe coming up from the slab cracked under the cabinet.
     

    Attached Files:

  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    You really don't want those galvanized pipe nipples and fittings. They WILL rust and corrode. Yes, I know that brass or bronze fittings cost more, but they'll outlast the house and never rust or leak.
     
  12. Terry

    Terry Administrator Staff Member

    Joined:
    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    His last pictures have the brass fittings. :)
     
  13. Jsmallberries

    Jsmallberries Member

    Joined:
    Nov 2, 2015
    Location:
    Zephyrhills, Florida
    Do you mean the galvanized stub outs from the top on the heater? One directly connected to the hot water supply, the cold side galvanized threaded stubbi to a brass "T" fitting with nipples and a right angle all brass. There was plastic piece inside the cold water stub out, didn't think I should try to pull it out.

    Are you saying i should add dielectric unions to avoid corrosion between the galvanized pipes and the brass?

    Anyway, appreciate the comments. All helps all good
    Or were you referring to the picture above my post? Not mine
     
  14. Bannerman

    Bannerman Well-Known Member

    Joined:
    Mar 19, 2014
    Location:
    Ontario, Canada
    I think Jadnashua is referring to BobbyH's photos in post #8.
     
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