I have a 3 zone baseboard heating system with an oil burner. My house is a colonial hse which was built in 87 and this is a recently started problem. The top floor (Bedroom area) has a thermostat and when the heat is kicked off it stops with a big banging sound. The sound is coming inside the walls where the hot water pipe is running. The problem is only with one zone (Bedroom area) and it is a big banging sound which sometimes scare the people. We can hear like somebody banging on the wall and it happens only when the zone valve or the heat is getting off. When turning the thermostat to get the temp. it doesn't make the noise, but when the reaches the desired temp and when it gets off it makes the noise. This may be a water pressure problem. I hope by my explanation you got my point and I am looking for a solution for this problem.