Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Expansion Tank filling up in closed system

Uni R_3
Uni R_3 Member Posts: 299
in THE MAIN WALL
Not both...

Comments

  • TaterHead
    TaterHead Member Posts: 2
    Expansion tank

    Trouble shooting hot water heating system in commercial application, kept getting air in system. Installed autovents on some problem areas. Finally sytem expansion tank (old style non captive) filled to top and started to leak around sight glass. Problem with system is there are high points and no way to bleed the air off all the system runs. Seems it was modified many years ago and unit heaters moved to accomidate new equipment. There are no bleed points on the end of runs. Trying the best I can, most pipe is welded 3" parallel system. First fix sight glass leak, then? Any comments?
  • TaterHead
    TaterHead Member Posts: 2
    Auto vents

    I installed auto vents on the heater that had no venting means. Not all easy to do without alot of down time. Too cold in NY this time of year to get really into everything.
  • Tim_47
    Tim_47 Member Posts: 4


    Do not use auto air vents on an expansion tank system ever. You must use air control. The air that is in the system on cold fill must remain in the system during operation (DO NOT VENT IT). The problem is probably in the piping of your expansion tank.
  • Unknown
    Unknown


    If the expansion tank filled to the top and started to leak water, couldnt the air have leaked out around the glass the same way. Or to put it another way did it leak air until the air escaped and then started to leak water?
  • Unknown
    Unknown
    I learned this ( thanks to Dan H)

    Steel expansion tank with auto air vent and wet rotor on return piping..... A big no no...
This discussion has been closed.

Categories