Orifice tube: an alternative to the expansion valve for some architectures of the air conditioning loop
The orifice tube is a tube with a given length and cross-section which expands the refrigerant but, unlike the expansion valve, it is unable to regulate flow rate and superheating.
The orifice tube is always associated with an accumulator at the evaporator outlet. Orifice tubes are made up of three main parts:
- A metal tube with a chamfered inlet
- A plastic tube body
- An inlet and outlet filter If the A/C loop is contaminated, then the orifice tube becomes clogged. In this case, replace the orifice tube.
The orifice tube must always be replaced when another important part of the circuit is replaced (compressor, condenser, evaporator, accumulator). Valeo info: Flush the A/C loop before installing a new orifice tube.