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Circulator/Bladder Tank Issue?

sixtog Member Posts: 10
edited February 2021 in Strictly Steam
Went to a job last night. The owner thought that the issue was the circulator and that the water was not circulating. I installed the circulator as he requested and noticed that the compression tank was no good, it was full of water. I turned the boiler on and she fired-- she ran for about 2 minutes and stopped. The water was about 180 degrees F. The high limit was set at 220 and the aquastat was set at 230. It had been working like this for awhile, according to the owner. I brought the high limit down to 190, but the problem was that the temperature in the boiler on the return side (bottom of circulator) seemed to be hot. However, the feed side of the boiler was only warm up to 3 feet above the boiler. That is when I put my hand on the pipe. I tried to bleed it, but the temperature was not going below 150. The boiler was not coming on. It seemed like it was not circulating, this is the first time I come across this situation. I need help, if you guys have any questions to get a better idea please ask. I've attached pics of the boiler below, too.


  • Jamie Hall
    Jamie Hall Member Posts: 23,324
    First question -- compression tank or bladder tank? If it's a compression tank, you need to empty it and then open the valve to the system and bring the system to operating (cold) pressure. If it's a bladder tank, you need to disconnect it from the system, drain it, and charge the air to just below the operating pressure. Then reconnect it and bring the system to operating pressure.

    So much for that.

    However, it sounds as though indeed you have poor -- or no -- circulation. I can't tell for sure, but it looks as though the pump is on the return. In either case, if you are getting circulation, when the boiler is firing the outlet should be very hot (with your aquastat settings) and the return should be markedly colder.

    First then I'd check is is the pump actually getting power? And, if it is, is it actually running? If it is you should be getting some circulation, even if it's rather poor. If the system has a lot of air in it, you may get poor or no circulation to the higher radiators, but you should get some -- and if that is the case, you may have to purge the system of air (bleeding is fine for small quantities, but for a lot of air, particularly trapped in pipes, not so much).

    A note: if you do bleed radiators, make sure the system pressure stays up. If you power purge, and you are dealing with a compression tank rather than a bladder tank, you would be wise to empty the compression tank again and re-pressurize the system when you are done.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    JUGHNE Member Posts: 11,062
    Is there a chance the new pump is installed backwards....not pushing into the bottom of the boiler??

    It has happened before.....easy to do.....

    Would you let us know?
  • Intplm.
    Intplm. Member Posts: 1,967
    Do you have a frozen zone? Ice in a pipe can do this sometimes.
    EBEBRATT-Ed Member Posts: 15,544
    I thought of the pump flowing the right way as others have mentioned.

    The other thing is those aquastats mounted on the long nipples can't work right the bulb is not sensing boiler water.

    Also you mentioned compression tank but it looks like a bladder tank in the back. What do you have?

    Do you have a pressure gauge on the boiler that your sure that it works? What pressure is in the boiler. You can put one on a drain fitting to check with a garden hose adapter
  • HomerJSmith
    HomerJSmith Member Posts: 2,441
    Why is it that I don't see a new pump in your photos? Did you just replace the cartridge in the pump? Do I see two expansion tanks on that sys?

    More photos from further away would be helpful. Is that pressure relief valve dripping?