3rd floor radiator - hydronic system

Unknown

Batcha the pump is on the return side and pumping toward to tank... got picture(s) of your boilers? There are some wetheads here are addicted to pictures here and won't admit its problem.

Greg Welter

Problem with third floor radiator

Hello. I've got a pumped hot water hydronic system and am having problems exhausting the air from the third floor radiator. The house is about a 100 years old. The AO Smith Boiler is about 27 years. That was when the system was changed from oil to gas. Don't know what else changed at that time. The pressure tank is located in the basement, at the same level as the boiler and the pump.
When I first moved in the automatic fill valve for the system didn't work and I had to top off the system manually a couple of times per season. When I had some repairs done to the boiler, they also replaced the automatic fill valve, and it worked fine for a few years. However, this year I'm having a problem. When I bleed the air from the third floor radiator (there is only one), it hisses for a minute or so and then stops. I close the bleed valve, and then a few hours or a day later bleed the radiator again. This has been going on for about two months. Can anyone suggest what the problem might be and how to fix? Thanks.

Mark Custis

There is not enough

pressure to bleed the high emitter. Bump, bleed, heat.