Subaru LEGACY 2002 Quick Reference Index page 508

EXPANSION VALVE
HVAC System (Heater, Ventilator and A/C)
2. FUNCTION
When the heat load to the air conditioning system increases, the refrigerant temperature at the
evaporator outlet rises and therefore the pressure P around the temperature sensing area in-
1
creases. As this pressure P becomes higher than the sum of the evaporator outlet (low-pressure
1
side) pressure P and the spring force F (P > P + F), the diaphragm is pressed down, moving
2 1 2
the valve ball connected to the diaphragm clear of its seat. This increases the flow of the refriger-
ant.
When the heat load is small, the action of the valve's inner elements is contrary to the above; the
valve ball closes and the flow of the refrigerant decreases.
H4H1124
AC-36