I changed a hot water heater while back now when I turn off cold water the pipes make a banging sound???

Question

now when I turn off cold off the the cold water pipes banging sound only the cold not the hot. Also in the shower it sound like air maybe in the lines. How can this be fixed.

Answer 1

check the isolaing valve b4 the unit if it has a jumper valve in it this can be bouncing causing the hammer change it to a duo valve @ check the washers in the shower these could be causing a problem as well

Answer 2

Have a plumber come out and bleed the air out of the pipes, make sure the cold water pipe is secured where appropriate, and install a bladder style hammer arrestor.