Pinnacle-Water Pump issue

[Oltman1]

We’ve got a 2016 Pinnacle 38flsa. Our issue is with the water pump. Sometimes, no problems. Other times, we switch on the pump and a terrible water hammer/vibration occurs for a good 3-5 seconds. Also, sometimes the water pressure is awful, other times, ok. We’ve replaced the shower head, replaced the water pump, verified that the unit is not in winterization mode and hooked it through city water instead of our usual dry camping. Nothing helps. Suggestion?

[Cosmik Debris]

I've found that the occasional water hammering is caused by trapped air in the plumbing. Found that it usually occurs if I drain the plumbing, move to another campsite, refill fresh water tank.
What I do to try and cure it is to let some water out of the low point plumbing drains. Once or twice and it usually goes away.