We had a new furnace installed about a month ago. The heating in our house is hot water baseboards. Ever since the new furnace was installed, when the heat comes on or turns off, there is a loud bang in the pipes. It's not 100% consistent, but it happens quite often.
We had the furnace company come back to look at the problem. They said it was likely water hammer because the new Honeywell valves flow twice as much water as the valves that were on the previous furnace. They only suggestions they had were adding padding around the pipes where they leave the furnace room and closing the ball valves on each zone a bit to limit the water flow. Neither suggestion helped.
Would it make sense to try and fasten the heating pipes coming out of the furnace to the walls in the furnace room in an attempt to limit pipe movement and hopefully reduce the sound? Does anyone have any other suggestions?
It sounds way too loud to be air in the pipes and it didn't happen with the old furnace, so something about the new furnace or piping in the furnace room must different enough to be causing this problem.
Best Answer
It turns out the problem was that the zone valves were installed backwards. They closed in the opposite direction of the flow of water. Since the zone valves were fighting the flow of water, it was causing a great deal of vibration and banging.
I had the heating company come back and reverse the zone valves so they operate in the correct direction. The banging is completely gone.