You might consider replacing it with an anti-scald model (which is NOT in the pictures above).
The above pictures were just a repair / replacement of the existing faucet. Its pipes (really copper tube) in the wall are arranged ONLY for this brand and model of bath tub / shower faucet (which is no longer approved in the Plumbing Code because it is not anti-scald). To have changed the type of tub/shower valve would have involved a minor bathroom renovation (tiles removed, etc).
Some of you may say that this is easily solved by turning down the hot water tank to 120 F. However, that is the point at which HARMFUL Legionella bacteria start to thrive. The catch-22 is that there is risk of SERIOUS INJURY from scalding if water is above 120 F. The answer to this dilemma is either a "pressure balanced" or "temperature sensitive" tub/shower valve so the mixed hot-cold water never goes over 120 F WITHOUT having to turn down your hot water tank.
The one in the top photo had several problems with it, so the home owner opted to buy a whole new assembly (instead of individual replacement parts - the knob was even stripped and wasn't turning anymore).
A more long-term solution would be to eventually renovate the bathroom (changing out / replacing the bathroom fixtures - Bath tub, etc.). In the process, you could change the tub/shower faucet to a new Plumbing Code approved anti-scald, single handle tub/shower valve.
Here is a picture of a new tube shower valve (with the anti-scald feature) we installed on another recent job.
Thanks for reading,
Jay Bortnik
Journeyman Jay Plumbing
780-266-3939
