Aquasource single handle - hot water pipes knocking

Evening folks, here is my situation:
I have installed a Aquasource Single Handle Tube and Shower Faucet. While the water is coming out of the tub spout everything works fine. When I pull the lever to send the water to the shower head the pipes start making a knocking sound. I have narrowed it down to only the hot water line. I can run the cold water without a problem but once I turn on the hot water the pipes starts making a knocking sounds.

I've tried clearing the air from the lines several times (to the best of my knowledge). One interesting thing is that if I don't have a shower head and just leave the shower arm there is no noise when running the hot water. Also, while the shower head is running the hot water and pipes are knocking when I turn on the hot water on at another place (like a sink) the knocking stops.

Aquasource Model #0071412.

Sadly, I am familiar with this problem because I have the same shower valve. I pulled it apart, cleaned it, reinstalled and still the same issue. My pressure is regulated with a thermal expansion tank and all other fixtures operate normally. I have narrowed it down to a cheaply manufactured pressure balancing system in the valve. It started happening about a year after installation. Exact same symptoms as you have described with the addition that the hot and cold mixing temperature is never consistent. A slight turn of the handle could go from cold to extremely hot. When my wife asks if I can fix it, I reply "Yes, when I have time I'll rip it out and buy a Moen or a Kohler." You may get some satisfaction from the manufacturer on receiving replacement parts and see if that works. I choose to replace it with a better quality from a plumbing supply house.
Lowe's may be able to put you in touch with customer service, but I believe that Aquasource is made by different companies and you have to match the faucet with the right manufacturer to get warranty parts. Similar to Pegasus faucets from Home Depot.

Caduceus, sorry to hear that. The faucet I got is 3 days old. I'm going to take it apart and take it back to Lowes and get a Moen or Kohler as you mentioned.

Not sure if it helps with anything but while the shower was running I went under the cabinets were the pipes are exposed. It is not the hot water line that vibrates. It is the cold water once the hot water is turned on for the shower head.

We ran into a similar problem on an entire apartment complex a couple of years ago. Placing shock arrestors on the hot and cold lines under the adjacent lav seemed to fix it. I don't know what the end resolution was, but it was enough to convince me that using cheap tub/shower valves is not worth the little bit of money you save over a Moen or Delta.

Yeah. My wife purchased it because it looked pretty and I warned her of potential problems. The vibration seems to actually originate in the cartridge (balancing mechanism?). I researched throughout the internet and found that this is an extremely common issue with the Aquasource shower valves and no resolution has ever been offered except for replacement.
She listens to me more regarding plumbing situations, now. Just because I'm a plumber doesn't mean I like to spend my free time fixin' stuff.lol.

I should have updated this a while back. I have gotten the noise down to almost nothing and is no longer a concern. I had to remove the spout and adjust the faucet to allow hotter water in. Now it only vibrates about 3-4 times when turning on the hot water. I haven't adjusted it to allow all of the hot water as I don't want my kids to get burned.

I recently installed an aqua source single handle shower diverter for a tub and shower. I installed the unit in my new shower, after closing off the tub outlet. Like everyone else on this site i, had the severe banging, knocking, air hammer sound reverberationg throughout the house. Thought i was going to have to tear into the wall and replace the whole unit. But instead, i purchased a delta in2ition shower head for about $50. Now all there is a gentle spray with a sound like rainwater, coming from my shower head. Not even one knock since i installed the shower head about a week ago. Its too bad a product like the aqua source shower head is even on the shelf. For the $110. I paid for the aqua source, i could have purchased a much better unit.