Originally Posted By: wfaulk
My point is that in order to circulate, the pressure at the sink has to be greater than the pressure at the source. If the pressures are equal and the thermostat gate trips, why is the water in the hot water line inclined to move to the cold water line? It seems to me that you'd have to have some sort of motor, and the solutions I've seen along these lines do not have any such thing.


Ahh.. The ones I know about all have a pump to move the water around.

But the kind with added tubing to return water directly to the heater/tank rely upon gravity induced convection (cold water is heavier) rather than a pump.