Air bound hydronic system help

Flangehead

I was on a call yesterday, 3 zone hot water boiler, 3 circs on the return side of boiler, steel expansion tank with airtrol fitting in the overhead. I had to break into the water side to change aquastat. I did so and filled the system back up again. I bled air the usual way through drain valve next to each circ. Manually opened make up while bleeding. I got steady stream of water from each zone. I returned make up valve to normal operations, system pressure 14 psi. Not able to bleed air from radiation upstairs, no air bleeds installed. After all of this I can still hear water moving around when circs are running.Am I doing something wrong here, How do I establish an air bubble in expantion tank?

jeff_51

sounds pretty normal

the air eliminator should take care of the rest of the air if there is one. To set up the expansion tank, shut of the isolation valve to the tank after you shut the boiler down. Drain the tank all the way, open the isolation valve and reset the boiler pressure, If the tank is sized properly, you should have the proper amount of air in the tank. When using fintube I never install air bleeders on them. Always set up for forced bleeding which is what you did. If you have CI baseboard, bleeders will prolly have to be installed.

jeff_51

also

if you can, talk the cust into moving those pumps.

jeff_51

also

if you can, talk the cust into moving those pumps.

steve_29

What kind of radiation is upstairs?

Flangehead

air

There is regular baseboard upstairs, no air elimination device, the airtrol fitting on the bottom of the expansion tank has a vent screw. No air bleeders on the baseboard. I was thinking after I isolate the expansion tank and drain it down, while I'm refilling system pressure, maybe I should open the vent screw on the airtrol fitting until water comes out, then **** it, then I might be further ahead. Do you think I should install bleeders on the base board?

Flangehead

air

There is regular baseboard upstairs, no air elimination device, the airtrol fitting on the bottom of the expansion tank has a vent screw. No air bleeders on the baseboard. I was thinking after I isolate the expansion tank and drain it down, while I'm refilling system pressure, maybe I should open the vent screw on the airtrol fitting until water comes out, then shut it, then I might be further ahead. Do you think I should install bleeders on the base board?

steve_29

You should have some kind of air eliminator on your system such as an air scoop, vortex, etc., after refilling your system it is quite normal for the new water to release gas which will be eliminated by the vortex,etc.

Low water pressure in the boiler may also create this sound, make sure the pressure is correct, don't assume the gauge is correct.

steve_29

You should have some kind of air eliminator on your system such as an air scoop, vortex, etc., after refilling your system it is quite normal for the new water to release gas which will be eliminated by the vortex,etc.

Low water pressure in the boiler may also create this sound, make sure the pressure is correct, don't assume the gauge is correct.

heatguy 1

air in pipes

Try installing a spirovent in the supply before you branch off to the different zones. In the past i have had some customers who i have had repeated calls for air in the pipes calls, i installed the spirovent and have yet to have call backs for this problem.

jeff_51

nothing works better than a spirovent

and set the system up for force bleeding. Isolation valves on supply and return with a boiler drain before the retun shutoff, than you can force system water through the loop. Lot of times you just have to get the water moving and with pumping away and the spirovent, that air will often times come flying out of there. Do one loop at a time. Real easy

Weezbo

there is one minor technicality.....

after purging,only run one zone t a time for a half hour.......keep a sharp eye and ear to the rail....should only one zone be the Cause of the air.....see where i am going with that?