Service & King Valves on MRCOOL HVAC Systems

Service valves are brass fittings located on the outdoor condenser unit. They serve two main purposes:

1. Refrigerant Access – They provide technicians with connection points to check system pressures, recover, or charge refrigerant during installation, servicing, or diagnostics.

2. System Isolation – The valves allow refrigerant lines to be opened or closed, making it possible to isolate the indoor and outdoor sections of the system when needed (such as during installation or maintenance).

Single Zone Service Valves Open (without the caps):

Location:

• The service valves are typically found at the base or side of the outdoor condenser, where the refrigerant line set connects to the unit.

• On MRCOOL systems, you’ll usually see two valves:

  • Large valve (suction line): Connected to the larger insulated copper line.

  • Small valve (liquid line): Connected to the smaller uninsulated copper line.

Multi Zone Service Valves:

Multi-Zone King Valves open (without the caps):

A king valve is a type of service valve—typically a larger, multi-purpose valve located on the discharge or liquid line side of the condenser, especially in commercial or geothermal systems. It's called a "king" valve because it allows for full control:

• You can pump down the system

• Isolate the compressor

• Recover refrigerant

• Connect gauges

"All king valves are service valves, but not all service valves are king valves."

King valves & Service valves Closed (with the caps):

Valve Key: