Water Hammer issue
Before I start, I want to thank all for your advice and help! Please bare with me, it's going to be a little long. Also I've no experience in plumbing at all.
House Age: 10
Water Hammer: No water hammer issue before the remodeling
Waster Pressure: between 70-75
Expansion Tank: No
Water Heater: A.O. Smith 50gl
Water arrestors: Two at the washing machine
It's all started few months back when we remodeled our bathrooms. We remodeled three bathrooms. Two at upstairs and one at downstairs. We remodeled one bathroom at a time. Here's the order: Upstairs hall way bathroom first, then downstairs bathroom, and finally the master bathroom.
The water hammer issue was discovered during downstairs bathroom remodeling. We noticed that the hot water came out really slow and weak (no pressure), it's barely enough to take a quick shower. The issue was resolved after the contractor fully opened up the cold water to the water heater.
After the remodeling done, we can hear the banging noise at every bathroom when you turn off either hot or cold tabs, showers, and toilets. The banging noises were located some where else, not directly next to the tabs, shower heads, and toilets. For tabs, if you close slowly then there's no noise. So I started searching and reading the forums in regards to water hammer issue. Here the things I have tried:
1. Bleed the air out of the system (tried many times but no success)
2. Replaced the Water Heater (No more water hammer from hot water tabs)
Here's my questions:
1. Should I install an expansion tank first and try to see if that will resolve the problem?
2. If step 1 didn't resolve the problem then should I install PRV and try to reduce the pressure to 60's range?
3. If above steps didn't work then should I install arrestors on all tabs and toilets?
I appointments setup already for getting the quote to install expansion tank and prv for the next couple of days.