Air Bubbles in Forced Hot Air Heating System

Our house and heating system is only 8 years old and we have a well, no public water. Our second floor zone this winter has been getting air bubbles in it (for example, when the thermostat kicks on upstairs, you can hear a large rush of water and gurgling through the pipes in the wall) and this eventually tends to stop the flow of heat on the second floor. About once a week since December, we have to bleed the water and air bubbles for our 3 zones in the basement using a hose.

Other items: This winter has been extremely cold in New York. We have had no change in water pressure for the house. The system is a closed system and there are no air vents or release valves. We also have a water softener system and neutralizer system.

Can you give me an idea of what the problem could be - leak in the well piping to the house....extreme cold causes the aquifer to be low, (our well is 180 ft deep).....do the softener and neutralizer systems have anything to do with it? These are just some ideas I though of, but really don't know if they have any validity.

sounds like the system was improperly piped in the first place. One reason you keep getting air is because every time you purge the system you introduce mor oxygenated air into the system and your air eliminator is either not working or piped in the wrong place. I greatly prefer to use a SpiroVent on the feed side of the piping (right off the main header) rather than a traditional air scoop which I feel is almost a wast of money.

Response to Air Bubbles Question

Thanks for your note. Appreciate it. We are not sure if we even have an air eliminator. Our plumber never mentioned it, will follow with them. Question - by purging the water with the air bubbles in it from the 3 zones (we go from the hot water heater zone in the basement to the main floor zone and then the second floor zone finally), how would we be introducing new air bubbles? Where would they come from? That is why we were thinking this came from outside the house from the well.

There are only a few ways to fully purge a system of air.

The easiest is to put vent's/valves or something at the top of the system to let air out.

The hardest method is to use a vacuum pump to suck all the water and air out of the system and then just let the water back in.

My folks had problems with there system and a HVac guy came out with a little pump that sucked the system dry and into buckets. He then he opened a valve and it sucked the water/antifreeze back in to the system. The system has worked fine since.

Although really rare... There also have been incidents where there was air in the well water due to air leaks before the pump or due to a air injector for a non-bladder tank. A low aquifer can also let air get into the house water.

But in the end the system needs a air vent valve. Look for a valve someplace on the second floor. It might just be a small wing nut looking thing.

Could a simple saddle valve could work?

It would have to be added to the highest pipe on the second floor.
Then open it and let air and some water flow out as needed.

Edit: Murphy's law... Air will get into the system.

If the system is pulling in water then it might have a water leak someplace and this is just a symptom of a bigger problem.