Automatic Expansion Valve(Constant Pressure Valve)

One of the first automatic valves of is designed to maintain a constant pressure in the evaporator

Operates Under 3 Pressures

Spring

Evaporator

Atmospheric



When evaporator pressure drops spring pressure and atmospheric pressure will cause the valve to open

When evaporator pressure increases, evap. Pressure will overcome the spring pressure and atmospheric pressure and will cause the valve to close

Characteristics of A.E.V.

Space temperature controlled by thermostat not recommended for varying load applications as load increases the valve tends to close as load decreases valve tends to open used on critically charged systems only suction accumulator should be used due to possible flood back