E.J. Petrin
E.J….from your discription, it sounds to me like thermal expansion of the hot water pipe when it is first turned on. The piping in the space above the ceiling, is binding in straps that are ment to hold it in place, when the hot water flowing through it causes it to increase in length (expansion). As this expansion occurs the pipe jerks and stops then jerks and stops again and again till it reaches its full extension. As it cools down it contracts much more slowly, and makes little or no noise. New pipe clamps are available that have a lubricating effect as the pipe slips back and forth and during each heating and cooling cycle, and effectively reduces or elliminates the noise problem.Bud. Happy New Year. Suncoast Plumbing.. Sunny Florida..
