I have a regular outdoor spigot fed by a 1/2" copper pipe from the basement through a brick wall. I want to add a hot water feed to it, regulated by a valve to adjust temperature in order to make washing our dog a little bit more comfortable. I'd like to avoid drilling another hole through bricks.
My plan is diagrammed below:
Cold and hot come from the same main feed, with the latter passing through a tank heater.
Is this OK from the engineering point of view to add-mix hot water like this? Should I add check valves?
To put it another way, do bathroom faucets that mix hot and cold water do something more than just combine two flows together that I cannot emulate with a couple of Ts and a valve?