Pressure, flow, temperature
In car air conditioning the expansion valve has three distinct roles. It controls:
- the drop in pressure for refrigerant evaporation & cold generation
- the flow rate of fluid in the evaporator
- the evaporator output temperature
The expansion valve is always attached to the evaporator and reduces the pressure of the refrigerant fluid upstream of the evaporator. This drop in pressure results in cooling the fluid and it also transforms the refrigerant from the liquid to the diphasic state.
Performance and reliability
Valeo expansion valves provide accurate dosage of the refrigerant as required by vehicle manufacturers.
Taking roots in O.E. market Valeo expansion valves allow for a precise selection of the type of the system and its performance which guarantees correct operation of the entire ventilation and air conditioning system.
Synergy from the use of Valeo evaporator and Valeo expansion valve provides the highest satisfaction level of the AC cabin comfort.
Common expansion valve problems
The most common problems with expansion valve are linked with:
- Contamination due to polluted refrigerant transition and acidic products
A blocked expansion valve in open position can result in either a significant loss of cold or the destruction of compressor.
It is advised to replace the expansion valve each time when replacing the evaporator. Always use the high quality valves and never flush the expansion valve.