airlock on the upper DHW zone of my building

[jazzman]

Hi folks,
I called a plumber more than 10 times for the same issue. He was bleeding the airlock from the system but 3 - 4 weeks later or so....the airlock has been created by itself again. It's not only into 1 particular riser. Now, almost every unit on the top floor is effected (kitchen and bathroom). The plumber said, maybe because of the booster pumps were stopped but they are not and running all the time. No water or power interruption happened in the building. The second plumber said maybe there is a cartridge but as I said the problem is not only into 1 riser. I had a HVAC guy in beginning of the year. He replaced a faulty hot water tank relief valve for this particular zone. Is it possible that airlock to come from the hot water tank? Somewhere at that time the problem appears? What do you think? Thanks.

 

[Electroguy]

Could you have an air leak into the system? Someplace where you have suction, like just before a pump? Just a thought.

 

[Geofd]

check out spirotherm web site you may find something there

 

[TomFOhio]

If you keep getting air in the system then you probably have a small leak somewhere that your not seeing. Are there any pipes
underground before going upstairs. Check all the radiation good.

 

[jazzman]

Thanks guys. We found one of the booster pump does not provide a sufficient water pressure to the high floors of the building (there are 35 + roof). The pressure is not stable at all. My boss plans to install variable speed boosters instead to repair this old booster system .....which looks a good decision for me. At least the plumbers now have a logical explanation why this fucking airlock appears in the system every month.