Everytime a zone calls for heat in my four zone hydronic heat system, I hear the initial gurgling of water rushing in the baseboard units. I have installed manual bleeder valves in the baseboard units but no matter how many times I bleed each unit, I still hear the gurgling. Everyday I release the schrader valve on top of the boiler mounted air scoop, I get a 2-second release of air before it hits me with a shot of hot water. I've read that there's a certain amount of air in the city water supplied to the boiler which could be the reason for bubbles. However, I don't believe I'm adding that much water (other than from the occassional bleeding exercise) to cause the gurgling sounds. Is there a way to purge the whole system of air? Here's a schematic of my system: Boiler outlet | Air Scoop (with air vent (schrader valve) and expansion tank) | Four zone valves | Four loops return to common 1" pipe | Ball valve with boiler drain stop | circulator pump | boiler drain valve | return to boiler thanks,

I got my heat set at 70, and the temp is now 57. Usually since its boiler heat, I expect swings of 5 degrees, but this is almost 15 degrees. Check the gauges on top of the thing, and they seem alright (pressure and such), checked the pilot, and its lit. Checked some of the radiators, to see if they need bleeding, and water comes out right away, so that's okay. What other things should I be looking for? Any links where I can troubleshoot the system or somthing? Don't know the brand or exact numbers (PSI or whatnot) yet, but this is the second time this has happened since I closed on the house day before Thanksgiving. First time, it dropped to 55 at night, but had self-corrected by morning, it was when we were moving in, so I blamed it on the constantly open doors, and the fact that radiator heat takes longer to adjust.