This is an upgrade that some people might be interested in. I was having trouble adjusting the shower temperature to my liking and decided to see if replacing the original shower faucet with a single-handle faucet would help.
This is a view of my access to the shower valve. I was very lucky to have it so easy.
This is the original standard RV shower faucet.
This is the new faucet with the trim plate. Brass finish is not in style these days. I was lucky to find a local place that had a lot of old stock to choose from. I got this one for $50. Here I have it attached to a backing board and ready to go with the shark-bite fittings in place.
This shows the shower wall marked for the trim of the new faucet. The trim plate has a concave surface that required me to cut a rather large hole. I had to move the new faucet over about a half inch so it would fit.
This is the hole cut for the trim piece. I used a hacksaw blade and then widened the cut with a drill bit so the saw would follow the curve of the circle. I have a Roto Zip but using the hacksaw blade gave me more control.
This shows the new valve mounted in place. In the earlier picture I had an elbow fitting on top, but I took that off and ran the PEX straight up for about two inches to the supply elbow.
This is the front of the valve showing the completed installation. I need to put a dab of gold paint on the screw heads.
I tested the valve under pressure and found I had to add more teflon tape and re-tighten the connections, but after that it worked fine. The one-handle valve definitely makes adjusting the water temperature easier. I combined the new faucet with a new Oxygenics shower head with a shut-off valve. This upgrade was not that difficult or expensive. I would recommend it to any of you who would like to make your shower easier to adjust.
Moderator's edit: Reduce the size of one of the pictures to the forum's recommended maximum of 640 pixels.