Air in system

DEVILDG628

I have an Oil fired Buderus Boiler with a 32 Gallon Indirect storage tank. I have 4 Zones, Radiant Heat, DHW, 1ST Floor & Basement. My radiant heat has three zones past a mixing valve. I recently had my storage tank replaced a few months ago & there seemed to be air in the heating zones. I have purged the air out several times, but air keeps getting in the system. When by my boiler, when the radiant zone comes on, at times I can hear water "flushing through the pipes. The boiler pressure is good and everything else seems good also(expansion tank has been replaced recently & the pressure reducer(not sure of its trade name) is working. Why would air still be getting in the system? To purge the air out I put a hose, one valve at a time and drained it out while closing all 4 lower valves at the same time that are on the side of the boiler. After draining all 4 zones, I then opened those 4 lower valves....is this the correct procedure?

Jamie Hall

Particularly with radiant — but with any hot water system — you have to purge the air out. Which means running water through the system, one loop at a time, at high velocity (like direct from you domestic water) through an open drain. Just draining and refilling won't do it.

How exactly to do that depends on where you have valves and drains…

leonz

You have 2 air scoops and 2 automatic air vents??????????????????????????? that should not be.

Close the vent cap on the air scoop in the last picture and leave it closed as I believe you have no central point/ A "SINGLE" point of pressure change.

Check to make sure the vent cap is loose on your air vent on the boiler or remove it and place a load on the boiler by raising "ALL" the thermostats all the way up and just wait, the air will be gone soon.