Tag: low side service ports

A/C low pressure & high pressure service valve ports

Car a/c service ports.

Most Air conditioning systems use Schrader valves at their service ports. These valves are similar to tire valves, although they can never be interchanged. They are covered with caps (resembling tire valve caps), containing O-rings.

Unless the system has been completely discharged due to a leak, recover the refrigerant using the appropriate method and equipment before servicing any hose , line, or fitting.

Which port do you charge AC in car?

Although charging the system can be performed through either the high side or low side when the engine is not running, it must be done only through the low side when the engine is running. This safety measure prevents the high-side backpressure from entering the refrigerant container and possibly causing an explosion.

Use the manufacturer’s specification for refrigerant capacity. On most newer vehicles, a sticker is affixed in the engine compartment indicating the type of refrigerant , type of oil, and the refrigerant capacity of the system.

How do you add freon to your car’s air conditioner ?

The most accurate method to assure that the proper amount of refrigerant has been added to the system is to use a charging station that can be programmed to deliver a specified amount. It is crucial that the exact amount of refrigerant according to specifications is used. Overcharging the system can cause damage, and undercharging will cause poor performance.

Where is the AC service port?

The location of the ac service port will depend on the make, model, year, and refrigerant type of the vehicle. The easiest way to find the ac service port in any car is to follow the lines from the compressor all the way into the firewall. The A/C service ports will be at some point between the ac compressor and the firewall.

Are all AC service ports the same?

The low side service port the  is the smaller of the two ac service ports. In all car new models, the high side fitting and low side fitting are different diameters .This prevents connecting the service hose to the wrong fitting. Systems with different refrigerants also require differently designed service fittings. This is to discourage technicians from putting incorrect refrigerant or oil in a system and contaminating it. Do not try to circumvent them with adapters.

R-134a refrigerant systems use quick-connect fittings, like the type used on air tools, and this time the low side port is smaller of the two.

R-1234yf refrigerant systems use quick-connect fittings too, but with different diameter to prevent contamination with R-134a refrigerant systems.

Some older systems have three-way stem-type service valves at the compressor inlet and outlet ports.

Your service tools must have the proper connectors for the various service fittings, and the equipment used on one system should not be used on another.

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