Thank you for your question. There is no way to convert a 1500 series (dual handle) to a single function 1400 series faucet without changing the in wall rough-in valve. However, as long as the screw holes on your large round escutcheon plate are at the 1 and 7 o'clock positions and you do not have a push button shower diverter directly below the off and on handle, then any of the Delta tub and shower trim kits that start with a T17, except for the T17T series trim kits will interchange for you.
The cartridges that come with the new trim kits will not fit your valve body, so you will need to reuse your existing cartridge (RP32104).
Date published: 2017-04-03