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Why Compression Tanks Waterlog

HeatingHelp Administrator Posts: 637
edited March 1 in THE MAIN WALL
Why Compression Tanks Waterlog

In this episode, Dan Holohan shares the history of expansion and compression tanks, along with some troubleshooting tips.

Read the full story here


  • Erik_condo_treasurer
    Erik_condo_treasurer Member Posts: 1
    I'm the treasurer of a condominium that is a five-story row house built in 1882. We have a hot-water heating system. There's a tank in the ceiling above the boiler; I think it's an expansion tank, but I can't tell you what it does (if anything). I realize that's too simple a topic for a forum for professionals like this one! Anyway, for years our building (and various Brooklyn plumbers) have tinkered with our heating system to get it to work optimally. I think we are as close to perfection now as we have ever been. No longer does the relief valve need to be replaced every couple of years, nor does it open and poor water onto the boiler room floor. We know how to bleed the radiators ourselves. We don't constantly have to add water to the system at the reducing valve to get water to the top-floor radiators. We found a plumber who knew enough to add a diaphragm tank next to the boiler, which we think helped. And I learned how to replace a thermocouple, because ours breaks every 12 to 18 months. Still, I worry that very few people understand these systems the way Dan Holohan does, and believe there will be fewer of them around as time goes by.
  • Jamie Hall
    Jamie Hall Member Posts: 23,324
    edited March 1
    There's no such thing as a too simple topic, @Erik_condo_treasurer . That tank to which you refer was almost certainly a compression tank -- they were common. Also very poorly understood by modern plumbers and many heating professionals. The expansion tank your plumber added will do much the same thing as it was supposed to be doing -- though it won't last as long...but it's much harder to defeat.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • leonz
    leonz Member Posts: 1,137
    OH BOY;

    Please submit pictures of your boiler and it plumbing as I/we need to know what is there exactly as you cannot have a steel compression tank and expansion tank/bladder tank together on a hot boiler used
    for hydronic heating.

    Please take high resolution images of the plumbing attached to the tank in the ceiling.

    Please take a high resolution picture of the low water cut off switch on your boiler and its wiring and how it is connected to the triple aquastat.

    If you are comfortable doing it please take a picture of the triple aquastat cover and inside the cover showing the wiring diagram, after that please take a high resolution picture of the dump zone aquastat which is a single aquastat and remove its cover to take one high resolution picture of the inside of the cover and a high resolution picture of the dial settings on the single aquastat.

    Please take high resolution pictures of the circulators, valves, pressure relief valve, water feed valve and the pressure and vacuum gauges(if used) used in the heating.
    system as well.

    I/we would like to also see pictures of one or more the radiators and the piping for them as well.