Floor Mounted Hydronic Expansion Tank 4.5 or 6Gal - Do They Exist?

Discussion in 'HVAC Heating & Cooling' started by JustAnotherHomeOwner, Oct 22, 2020.

  1. JustAnotherHomeOwner

    JustAnotherHomeOwner New Member

    Joined:
    Oct 22, 2020
    Location:
    Toronto, Canada
    Hi all...

    TLDR: Any suggestions for brands who make a 4.5 or 6 gal hydronic expansion tank designed to sit on the floor? i.e. Air-valve not on the bottom, with appropriate stand/feet/legs

    I have a *very* small mechanical room with a lot going on. I have a 125,000 BTU/h combi-boiler " feeding 1000' of underfloor, a couple of towel warmers and an air-hander for a 2500 sq ft house. Plus HRV, plus humidifier, plus air-filter, plus central vacuum, plus low ceiling crowded with ducts. etc.

    Back in 2003 my installer - who did overall did a very good job - no major issues in 17 years - put the expansion tank 1/2" from the floor, so I can't access the valve to check the pressure or recharge it. :-(

    The tank feels very heavy so I suspect it has failed... and the tank position will make it really hard to install a new combi-boiler (moving from NTI T150 - parts no longer available - to a Viessmann Vitodens 100-B1kA).

    The only position for the tank my installer and I have come up with means the tank needs to sit on the floor. There is literally no wall or ceiling space left. We can't even run straps to the ceiling because directly above where the tank would go is the HRV. Yes, we're assuming hanging a ~60lbs tank (when it fails and is full) from the underside of the HRV is not a good idea (too conservative?)

    The system was sized with the earlier version of the Watts ETX60 (6 gallon), but I suspect I may be able to use a slightly smaller 4.5 gallon - my installer is doing the math. This may help.

    My installer and I thought this was going to be easy since there are plenty of larger tanks with stands...Watts has the whole ETSX line!

    But no... I can't find a single hydronic expansion tank of this size that is designed to sit on the floor... i.e. water line on the top, and air valve low down on one side where you can get to it!

    Any suggestions of brands who might have a 4.5 or 6 gal hydronic expansion tank designed to sit on the floor?
     
  2. JustAnotherHomeOwner

    JustAnotherHomeOwner New Member

    Joined:
    Oct 22, 2020
    Location:
    Toronto, Canada
    So my installer and I have come up with some options if such a floor standing tank doesn't exist... but we don't like any of them... :-(

    TLDR: Anyone offer 2nd best option to use a regular tank with air-valve and water line on opposite ends?

    What we've come up with... use a regular tank and...

    (1a) mount tank on its side with a wood "cradle".. but this really starts to encroach on pumps and valves that may need servicing

    (1b) build a wood stand and permanently attach a flexible extension to the air valve on the bottom of the tank for later use (if such a thing exists) ...

    (1c) build a taller wood stand and mount the tank with the air valve on top... this would require running a pipe very close to the floor to attached the water line with shut-off valve / drain-port... which somehow feels wrong...

    So...these feel like real kludges.


    (2) We could suspend a regular tank away from the wall... if we could have a 6" gap between the side of the tank closest to the wall and the wall itself (there are pipes on that wall which we don't need to access for servicing). There is space between the pipes to mount the Flamco Flexconsole Hanger - which would be perfect... but it is ~3" too short :-( and they only seem to make one size.


    (3) Use the Flamco Flexconsole Hanger with a tank which is the appropriate capacity but only 6" in diameter and less than 18" high (very unlikely it seems), or one where the water line is off-set from the centre of the tank (also seems unlikely, unless someone knows different?)


    (4) Current last resort: Have a metal bracket custom made... but that seems a little ridiculous.

    Anyone offer an option 5 or 6?
     
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  4. wwhitney

    wwhitney Well-Known Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
    So the flexcon 18 won't fit with the flexconsole hangers mounted on the wall because of the pipes on the wall? Can you mount some vertical unistrut to standoffs on the wall, and then mount the flexconsole hangers to the unistrut?

    Cheers, Wayne
     
  5. wwhitney

    wwhitney Well-Known Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
    Or if the air valve on the bottom of the expansion tank is threaded in, how about removing the valve and adding an elbow and an extension to move the valve to an accessible location?

    Cheers, Wayne
     
  6. antonyupward

    antonyupward New Member

    Joined:
    Apr 8, 2005
    Location:
    Toronto, Ontario, Canada
    Thanks Wayne... you are correct in terms of the situation

    When you say "Flexcon 18" - do you know of one that is 18" long (the ones I've found are all 275mm / 10.83")? If there is an 18" version, or even 15" that would definitely solve the problem....

    If I've misunderstood (likely)... I guess we could fabricate an extension to go between the wall and the Flexcon... but looking at the Unistrut system you recommended... if I read the load table right... they have a 450mm long strut that can support 100Kg at the end (1kN) - and that tank is ~25kg when full (~60lbs).

    So perhaps my 4th option of having a custom bracket could be replaced by "Buy appropriate unistrut" - I like that possibility!

    If we ran the pipe with shut-off valve along the top of the strut and secured it appropriately then we could "dangle" the tank off the end :)

    Any idea where I can buy Unistrut or similar in Canada?
     
  7. antonyupward

    antonyupward New Member

    Joined:
    Apr 8, 2005
    Location:
    Toronto, Ontario, Canada
    You mean like one of these "Sasonco Valve Stem Extension 90 Degree Air Tire Angled Schrader Valve" :) LOL

    You don't even have to take the tank valve out if understand right.

    Would need something a little different from the one I found in 90seconds... 90 angle with no valve + 7-8" straight with a valve... but have to believe another 90 seconds would find what I need :)

    Brilliant Wayne... thx so much
     
  8. wwhitney

    wwhitney Well-Known Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
    Flexcon tanks are labeled by their volume in L, just go to the tanks section on the flexcon website.

    As for mounting unistrut, if the pipes are on the wall, the tricky part is the stand-offs. You could probably bodge something together with wood 2x4, but I think unistrut is often the go to in these situations. Did you find stand offs for unistrut?

    No clue on Canadian procurement.

    Cheers, Wayne
     
  9. JustAnotherHomeOwner

    JustAnotherHomeOwner New Member

    Joined:
    Oct 22, 2020
    Location:
    Toronto, Canada
    On flexcon I think we've missed each other. I'm talking about a Flamco support arm, not a Flexcon tank :) See: Flamco Flexconsole Hanger If anyone is aware of a longer version / equivalent that would be helpful.

    On the unistrut... The good news is that I think a unistrut will fit between the pipes so I can secure it direct to the wall the pipes are mounted on, then arm of the 450mm / 18" strut will protrude far enough to hang the tank on the end have the clearance between the tank and the pipes.

    So I think no standoff required :)

    Thanks again for your thoughts Wayne!
     
  10. wwhitney

    wwhitney Well-Known Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
    Right, and my first post was referring to both. Because my first thought about tanks that would fit those hangers was to look at tanks from the same manufacturer. Hence I asked about the Flexcon 18 tank mounted using the Flexconsole Hanger, and how much interference there would be with your pipes.

    Cheers, Wayne
     
  11. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    1. SX-30V [​IMG] 15-3/8 diameter. 14 gallons.

    2. Hang a drop ear elbow from a member you build from strut (or whatever) at some place. [​IMG]
    Lots of different choices. This one is fed with 1/2 inch pex, but has the 3/4 inch NPT to hold a tank.
     
  12. fitter30

    fitter30 Active Member

    Joined:
    Feb 2, 2020
    Occupation:
    Retired service tech
    Location:
    Peace valley missouri
    Strut L bracket short piece of strut two long hose clamps. Repipe ex tank water in the bottom.
     
  13. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
  14. fitter30

    fitter30 Active Member

    Joined:
    Feb 2, 2020
    Occupation:
    Retired service tech
    Location:
    Peace valley missouri
    Water heater ex tank can be pipes upsidedown
     
    antonyupward likes this.
  15. antonyupward

    antonyupward New Member

    Joined:
    Apr 8, 2005
    Location:
    Toronto, Ontario, Canada
    Yes I think this is the conclusions I'm coming to too! Thank-you for your input. Appreciated.
     
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