How to add circulation timer pump to passive recurlation system.

Yeah Title 23 says no from what I recall - must be a demand activated which is the better option anyways. The where depends on your piping system - with then exception of homerun types of systems, hook one up under the sink "The on-demand pump is generally located under the furthest sink and ties into both the hot & cold water side. Once you press the button it starts drawing water from the hot side returning it to the cold side until it senses a temperature change & it shuts off. Voilà you now have hot water at the faucet." (nothing says you cant have one in the master & also furthest, especially if no one ever uses the furthest, etc...) For more: http://thehtrc.com/2013/fix-a-leak-with-watersense-program