Question
I have an Irritrol 1" valve that has 23 pop-up spray heads. It has always been fine for over 20 years. Here lately, I get one loud bang noise in the house every time it shuts off, Not a chatter, just but one bang. Would it be better to add another valve and split the load, or install some kind of an "air chamber" shock arresting device. What kind of a device would be best? Would it get installed in the main line from the house, right after the Backflow Preventor? Once again, thank you in advance for your help.

Answer
Hey Bill, before you go to the expense of putting in a water hammer arrestor, you might try rebuilding your automatic valve, or replacing your automatic valve. Some valves will shut down more slowly and some will shut down fast. First try installing a new diaphragm in your existing valve, if this doesn't do the trick, check with your local irrigation supply store, and replace the existing valve with one that shuts off at a slower rate. If you need to install the arrestor, install it after the backflow preventer. Good luck and have a great day.