Hoping someone can help. We had a few water lines moved a while back because we were finishing our basement. Right after the changes, we heard a few clanks each time we turned on the hot water. The noise went away, so we figured it was nothing - maybe just some adjusting or something from the change. Well it has come back. It sounds like three to five clanging sounds each time the hot water is turned on. It sounds like it is coming from the water lines themselves, though I'm not sure at this point. If we use hot water again within a short time, it won't happen. Only if it sits for a little bit. Any ideas??? Thanks for any suggestions you have!
Water hammer would be the first culprit I would think of. Could be possible that some eliminators were removed with the old pipe. Some non-commercial eliminators are just a piece of capped off pipe on the waterline and extended up 8 to 12" above the supply take-off. Could also be that the new lines (or old ones) are not secured to studs and when used, they expand and knock against the walls or studs. Being the hot water lines, I am suspecting expansion/contraction.
If you have never made a mistake, you haven't done much.
The piping is too tight inside the holes it is passing through so as it expands as the hotwater comes through it is hanging up on the framing, other than opening up the walls and enlarging the holes your kinda stuck. I see this with drains a lot more than water lines but I see it often.
Water hammer would only occur when you are stopping the flow of water.