Water Gage & Banging Pipes

Tony_37

Anyone who could chime in,

We moved into a 6-unit co-op with steam heat. Got surprised by the banging pipes. We're right above the boiler and the supply pipes in the basement.

As far as I can tell:
- Its a gas fired two-pipe system
- the banging is in the supply pipes and not the radiators (we definitely notice it more on the first floor)
- The supply pipes are insulated
- The water gage is all the way full
- Its an older building (1920), so the supply pipes may have settled and not have the proper draft. I haven't checked them yet with a laser or water level.
- It seems to bang the most on system startup (like there's an angry chimpanzee in the basement), but there are also some occasional knocks during the cycle.

The system gets "serviced" every year. When we couldn't take the banging, we brought the service company in. I'd read up a little online (this site is great) and hoped that the service person might go about troubleshooting the system. Basically, he just drained a couple of buckets out of the boiler and said we needed to do that occasionally.

Problem was that the water level in the gage rose back up to the top of the gage after he had drained enough to see an air bubble. Sounded like it was an automatic valve letting the water in. The service person just looked at it like, "Hmmm... that's not supposed to happen," but didn't suggest anything to fix it. I thought the water level should be hanging out around halfway up the gage.

On his second visit, it was the same prescription. Drain water out of the tank.

I'm not an expert (yet), but it seems like there might be more to this problem. Should we start looking for a more inquisitive and experienced steam heat service provider?

Location - Urbana, IL. I was thinking of asking the University of Illinois who they would recommend, since I think a lot of their buildings and dorms are steam heat.

Thanks for any suggestions. I'm relatively mechanically inclined, so if our building can't figure this out with a local service company, I may need to get "the book."

Tony

Daniel_3

Well, there's your problem. Water in the gauge being carried into the supply risers and going apeish. Either the auto fill valve seat is leaking or calling for water abnormally. Me? I prefer a manual fill. Get that fixed and you may eliminate the hammer from those filled supply pipes. I just don't trust those auto fills as they give anyone an excuse to not bother with going down into the basement. . . I won't discount the probability of sagging pipes though highly unlikely given your description. I'm assuming the pipe sizing is accurate if the dead men did it. Replaced pipes recently?