What Is an AC Service Valve?

Air conditioning systems often require servicing. Maybe your air conditioning system has low pressure, or perhaps it has a refrigerant leak. For refrigerant-related servicing such as this, a service valve may be used. What are service valves exactly, and how do they work?

Service Valves Defined

A service valve is an accessible port that allows heating, ventilation and cooling (HVAC) technicians to service the refrigerant in an air conditioning system. They are typically made of copper tubing. Most service valves have several ports. Refrigerant will flow through some of these ports, and HVAC technicians can access other ports.

HVAC technicians can connect equipment to service valves to perform refrigerant-related servicing. They can use service valves to adjust refrigerant levels, for instance. If there’s too much refrigerant in your air conditioning system, HVAC technicians can lower the refrigerant level by accessing a service valve. If there’s not enough refrigerant in your air conditioning system, on the other hand, they can increase the refrigerant level by accessing a service valve.

HVAC technicians can also perform tests using service valves. They can test the pressure of refrigerant gas, for example, by connecting the appropriate equipment to a service valve.

Where Service Valves Are Located

You can find service valves in refrigerant lines. Most residential air conditioning systems have several service valves. They have a suction valve and a discharge service valve on the suction and discharge refrigerant lines, respectively. You may also discover a third service valve, known as a king service valve, on the receiver outlet.

The 3 Positions of Service Valves

Service valves support different positions. Adjusting a service valve will change its position. Common positions supported by service valves include back seated, mid seated and front seated.

The back seated position is used during normal operating conditions. The service port is sealed when a service valve is adjusted to the back seated position. The mid seated and front seated positions are used during servicing. When adjusted to the mid seated position, HVAC technicians can access the service port.

In Conclusion

If your air conditioning system has a refrigerant-related problem, an HVAC technician may use one or more service valves to fix it. Service valves are ports in refrigerant lines. They provide an access point for HVA technicians. Rather than disconnecting the compressor or other air conditioning components, HVAC technicians can connect directly to a service valve to perform refrigerant-related servicing.