AC Accumulator. Orifice Tube System Layout
The accumulator plays a role in removing debris, oil, and moisture from the AC system as being a part of it. It also prevents any remaining liquid refrigerant from returning to the compressor. The accumulator has a desiccant to consume moisture. It is located on the "suction" or "low-pressure side" of the AC system, between the evaporator and the compressor. Any excess liquid refrigerant or water droplets that enter the accumulator flow to the bottom of the accumulator; whereas, the vapor refrigerant passes through the desiccant before flowing out of the accumulator.
The AC system, where the accumulator is also included, uses an orifice tube. The valve helps control the flow of refrigerant through the evaporator, which is the main cooling component of the system. An expansion valve controls this flow directly through a modulating rod, which opens and closes to various levels depending on cooling demand. This system uses a thermostatic switch or “pressure switch” to cycle the compressor clutch, to control the evaporator temperature. The orifice tube is also responsible for preventing the evaporator icing or flooding. In the picture below you can see that the orifice tube is located between the condenser and evaporator:
Some vehicles use an AC accumulator orifice tube while other vehicles include an expansion valve instead of the orifice tube and a receiver-drier instead of the accumulator.
Symptoms of a Bad Accumulator and Orifice Tube
The accumulator allows the moisture to enter the system when it becomes exposed to the atmosphere. The desiccant consumes the moisture, which becomes filled with it. This can cause the corrosion of the system. The Orifice tube can freeze because of a lot of condensation has been consumed by a desiccant, which stops the refrigerant to flow in the AC system. The orifice tube can also get blocked by the debris collected in it.
A failed accumulator or orifice tube is not able to provide efficient cooling performance. You will start to hear a rattling noise from the failed accumulator when the AC is working. If the accumulator is cracked, the refrigerant will begin to leak, which you can identify using an ultraviolet leak dye. The AC gauges can determine a failed orifice tube. If it shows wrong readings or fluctuations, then check the orifice tube immediately and replace it as soon as possible.
Whenever you replace the compressor, replace the accumulator as well for efficient cooling performance. It will also prevent from any other failure in the compressor due to any moisture or other foreign materials that can enter the compressor if you have a failed accumulator.