Hi, my water heating pipes makes banging noise when heat is coming in a hot water boiler heating system. My water pressure gauge keep coming down where I have to keep adding water back to the boiler. Is there something wrong with the expansion tank that is pressuring air to the pipes? Thanks!:confused:

Usually air in the lines is the cause of noise (banging). Water pressure gauge drop usually is a indication of water loss. (check for a leak in your system).

Expansion tank. Isolate shout off valve to tank and drain Reopen valve. If you have a auto feed it could also be defective.