Ive been asked to look at splitting a heating system into two areas in a small workshop with offices upstairs. at present it has a 54 kw boiler fitted with a time programmer and trvs on all radiators, both up and downstairs. when it gets too hot in the offices they simply switch off the boiler until it becomes cooler. my question is this, can i simply fit two port valves on each flow to isolate each floor? if i do this can they simply be operated by a room thermostat that can be wired through a spur without wiring them back to the boiler, and simply opens and closes the valve. Do i need to control the boiler by any other means and will the boiler be o.k if both valves close at the same time.