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3 Zone Boiler needs to be bled of air every fall?

Mobius1 Member Posts: 3
edited November 20 in Oil Heating
Hey Everyone. Looking for some advice. I bought a house back in 2017 and replaced the boiler and hot water tank in 2019. Buderus G115 boiler, Reillo 40 Burner, an Amtrol PurePro 41 gallon water heater, and 3 Taco007e circulating pumps.

All summer long the system is fine and feeds the hot water tank without issue. Once turn the thermostats on, somehow the water heater loop gets air locked and we have to bleed the system out. If the water heater runs by itself it's okay, but as soon as one of the other zones is on at the same time, the water heater loops pump will start blinking 2 times and it no longer circulating.

I never had to do this with the old system. Once it's bled it seems to work fine for the winter. But once we stop using the heating zones for a couple of weeks or a month, and turn them back on, we have issues.

The installer says this is normal and has to do it in his house every year. What do you guys think? I've never had to bleed a heating system unless there was a repair being made. He did come the first couple of years because there was a warranty on the system, but now I either have to do it myself or pay someone.

I did try and bleed the radiators a couple days ago, and it's possible I missed one because it's not quite right. The water heater is fine until one of the other zones kicks on and it stops circulating. The air vent on the boiler loop seems to work, I can unscrew the red cap and air comes out and sometimes just a drop or two of water. But it's not enough to get the air out of the system.


  • Jamie Hall
    Jamie Hall Member Posts: 22,085
    Shouldn't have to do that. The system should maintain pressure -- and therefore not leak -- all summer. However, it sounds like a very small leak, and you are going to have a time finding it. The comment by the plumber that his does the same thing is not encouraging.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • hot_rod
    hot_rod Member Posts: 20,725
    it could be an air vent is allowing air into the system
    This can happen on systems with the pump to expansion tank relationship

    Post some pics of the boiler piping
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • pedmec
    pedmec Member Posts: 807
    your going to have to post some pics of the boiler and piping. you shouldn't have to bleed air out.