Hot Water Pipe Noises
Posted by Greg Saraceno on October 21, 2002 at 17:13:21:
We have a new house which has an interesting plumbing noise. Here are a list of characteristics:
- The noise only comes from the hot water line ( copper plumbing used in house). House is a 2 story with full basement.
- The noise only comes from one first floor bathroom (shower, tub, and 2 sinks all make the noise) which is at the opposite end of the house from the water heater.
- The 2 other bathrooms (one on first floor, one on second floor), kitchen, and laundry room do not cause any banging in the hot water pipes.
- There is ~ 37 feet of straight horizontal copper pipe between the hot water heater and the noisy bathroom, where the first 31 feet are 3/4" pipe and the last 6 " and all vertical pipe to the bathroom is 1/2" pipe.
- There is no more than 12 feet of straight pipe between the hot water heater and any other hot water sources. All other hot water sources are within 25 feet of the hot water heater.
- The noise is a banging in the hot water pipe that occurs for ~ 15 seconds whenever the hot water is turned on. The noise occurs in the pipes roughly below the item being used (sink, shower, or tub).
- Once the banging stops the hot water is fine.
- Several minutes after the hot water is turned off the pipes will let out 5-20 single 'bangs' which take 15-60 minutes to stop. Every few minutes there's a 'bang'.
- Once the pipes stop banging and the hot water is used again in the noisy bathroom the process can repeat itself.
- There is an air chamber/damper ~ 6" tall on the hot water line immediately above the hot water tank. The cold water line also has one.
Thanks in advance for any help!
Best Regards,
Greg Saraceno

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