I bought a basement condo a year ago and my neighbors heat pipes goes through my bedroom. Since the day I moved in his furnace has been making clicking and loud banging noises. Last year, we have had a couple of plumbers come in and they have bled the pipes and said that should take care of it. But it doesn't. The noise continues.

I live in a very old house that was built in the 1800's and my neighbor has an old furnace that I was told was about 15 years old. It is a gas hotwater furnace. This winter we had another plumber come in and once again he bled the pipes and added a solution that was supposed to pick up the rust from the pipes. Since that was done the banging noise has gotten even worse. The plumber said that the system could be really dirty which would be causing the noise so I have been bleeding the pipes every 3 days since and when I do it the water is completely brown full of rust. I have probably bled it myself three times since the plumber came. Is that normal? Should I continue to bleed the pipes in hopes that the banging noise will stop. Do you have any other suggestions on what I should be doing?

On a typical hot water heating system, the pressure in the pipe is about 20 to 25 PSI, do you know what is the pressure in your system, if the pressure is too low, you can't bleed all the air out of the system. It is the air inside the system that is causing the Banging Noise. There should be automatic air vent build on the highest point to release the air from the system as well.

Thanks for responding so quickly.

No, I don't know what the pressure is. How do I find that out? The weird thing is we have had three plumbers and they all said that the furnace was in good condition. They never mentioned that the pressure was too low.

I don't know how your system is setup, some system are connected to the house water supply, from the house water supply, connect to pressure reducer from 80 psi (city pressure) down to 30 psi and to a Back Flow Preventer, so that it doesn't flow backward to the house water supply, that is how this type of system maintain the proper pressure. If the system is old, the water reducer or the back flow preventer may be plugged and is no filling, this may required to be replaced, and also you keep bleeding the system, every time you do bleeding that you let more pressure out of the system if no refill.

The other type is close loop and not connect to external water source, this type, you can only fill with a pressurize system.

Usually they fill it with 50% glycol and 50% water.

The only way you can tell the pressure is from a pressure gauge, usually there is one installed in or near the furnace. If it is below 15 PSI, you need to fill to 20 PSI minimum, bleed it and fill it back up to 20 PSI again until the system has no air in it. If there is no pressure gauge, it is a good idea to install one, I know Home Depot sells it for about $15.00.

Good luck!

I don't know a lot about plumbing, but I can offer a possible cause for the noise. This may have nothing to do with your situation, but it can't hurt to read it. I was having vibrating noises (water hammer) caused by my dishwasher and this corrected my problem.
Water Hammer & Plumbing Pipe Noises