There was a question I neglected to ask in my previous note. How do I fix a situation involving a radiator. Whenever the boiler turns on and it begins to heat the system, there is a radiator that makes a loud noise as if someone is banging it with a metal object. How do I fix that? Thanks again for your attention in this regard.:confused:

Depends is this hot water or steam?

It's hot water on three radiators and a lot of steam on another with dripping hot water.

I have not heard of a steam hot water combo before. It is usually hot water OR steam.