My baseboard, hot water furnace has been making a loud noise in the baseboards. I have always had electric heat so this is new to me. The furnace is about 10 years old, and I think it may be out of water or too much air in the system. The PSI's are not registering. Any idea why this is happening?

Could be a leak. A full expansion tank. Air in the system. Bad auto fill valve. I manual fill valve give it some water.