Assertion: hot water | /r/CapableOf | contact the valve
Facets:
value: to control crossover flow
type: PURPOSE
Source sentences:
text: The first of two system types has a pump mounted at the hot water heater while a "normally open" thermostatic control valve gets installed at the farthest fixture from the water heater and closes once hot water contacts the valve to control crossover flow between the hot and cold lines.