Originally Posted by amirm
1. The Flojet on-demand pump made a huge racket. Turning the shower caused the whole side of van to vibrate. Popped the access panel at floor level by the heater and the problem was obvious. It was not the pump! But rather, a length of Pex pipe that went to an elbow. The pipe was cut just a hair too long causing it to touch a metal part of the chassis. That in turn amplified the sound ten fold.
3. The water pressure in the sink faucet was very low. When you first started it, you got nice flow but it would go to a trickle with the pump cycling on and off instead of increasing run time to keep up with pressure.
I've found the water pump makes a lot more noise if there's even a small amount air in the pipework. It takes some persistence to get out all the air, by opening each of the faucets in turn and moving the handle from cold to hot to cold, etc. The noise comes from the pipes vibrating against things along their runs.