Originally Posted by fhenn
Pull the shower head and check the screen some times all sorts of junk gets in there and clogs up the screen
Good point, I forgot about that. Especially with a new coach, there can be foreign material left in the water lines from manufacture. As well, scale and other foreign particulate matter can easily get into the water system through use.
When I owned boats, clogged shower heads were a common occurance.
One other thought - again from having boats. Many of the marine type water inlets (which are very similar to RV) have built-in regulators; integrated into the water inlet, which can be up to 65psi.
Boats also generally use the same PEX type hardware that are common on RVs (the two boats I owned having pressurized water systems used PEX). This does not automatically parlay into being able to use 65psi for a RV, but it does suggest the PEX hardware is fairly robust.