purge system? expansion tank?

I have a circa 1966 hot water system with gas boiler. Two zones, one a walk out basement and the other the first floor. I am doing major remodeling and winter is coming. I have cut off the basement zone and capped off for future piping. I had to remove some baseboard in the first floor zone, and have repiped. Zones are simple loops. The system worked fine before I started this project. The system sat empty for three months. Some of the valves are hard to operate.

I have now filled the system and purged to best of my ability. Boiler heats to 175 degrees on gauge. Pressure shows to be 18 psi, but I have no heat in the active zone. Pictures of boiler piping and expansion tank are at

http://cheely.com/expansion.jpg

http://cheely.com/boiler.jpg

Expansion tank seems to be empty, even with fill valve open. If I purge through the valve on the right, I get lots of air that doesn't stop, which may be coming from expansion tank. How should I be doing this, why is expansion tank apparently empty, and do I leave fill valve open when operating system?

Thanks

 

Purging should be done on the return side of the boiler. If the pipe coming down on the right side goes to the circulator behind the boiler & that is the loop you are trying to purge, it should work to a large extent. If it is on the supply side, you need to be purging thru the black valve on the left side of the boiler. Since there appears to be no low water cut-off on the boiler, the feed valve should be left open.

 

Just a thought but your circulator may be stuck. If it has multiple speeds, switch it to high speed and try again. When the system was drained and the air got to it, it may have rusted and won't start. It will get hot but not pump if it is stuck. You may have to replace it if it won't work. It may also be air in the loop because when the purge is done correctly, there will be no more air coming out of the purge valve.

Ken

 

Something's not right here. I can't get the expansion tank or the fill pipe to the boiler to have water. They both ring hollow. I've opened the pressure valve and purged air. The zone purges fine - no bubbles. There is a B&G FB-8 before the tank which appears to be ok. In fact I operated the lever that apparently bypasses the 12psi limiter and blew the boiler expansion valve open. There is a B&G ATF-12 after the tank. Is there some way to bleed that valve to make water fill the tank and the fill line? Thanks.

 

Your system uses the B&G Airtrol setup. Open the hex bleeder on the red expansion tank fitting and wait until air comes out. Then close it and the system should be filled correctly.

Ken

 

Well, through whatever combination of purging (I don't think I was doing it right at first) and messing around with the expansion tank, I've got heat. And it doesn't make any noise.

Thanks for the help!