Hi Dan, Thank you for your question. The orange switch on the RP50587 cartridge controls the Handle Limit Stop. When the switch is set to the left, the handle has the full range of motion between the hot and cold temperatures. When the switch is set to the right the handle motion limits the amount of hot water in the mix.
Thanks,
Dave
Answered by: DeltaFaucet2
Date published: 2018-09-03