701JRS-series Phillips Pilot Operated Valves

The 701S Series Low side valves are pilot operated valves which meter the flow of liquid refrigerant to an evaporator or pressure vessel in response to liquid level requirements. The 701S is controlled by a float valve which responds to changing requirements, providing a modulating control arrangement. The 701S valves are flanged and may be supplied with a mating strainer. A metering plug and spring are selected for specific operating conditions. A manual opening stem, for raising the metering plug off the internal port, and a replaceable PTFE seat disc are standard.

In fixed level applications, the 701S is typically controlled by a 301E float valve. The 301E is mounted in a welded steel chamber, external to the vessel where the level is being controlled. The chamber is equipped with a Phillips Level Eye for visual indication of the liquid level. A 300H Series float valve, which mounts internal to the vessel being controlled, will also serve as a pilot float.

In adjustable level applications, the 701S is controlled by a 101 float valve. The 101 valve has an adjusting stem which permits the operator to change the level being controlled in the vessel or evaporator. This valve is also mounted in a welded steel chamber external to the vessel, and is equipped with a Level Eye.

The 701S valve is actuated by controlling the pressure above the internal piston. A drop in liquid level, detected by the pilot valve, reduces pressure in the pilot line as the pilot orifice opens. This drop in pressure causes the 701S piston to rise and open slots in the metering plug. Conversely, a rise in liquid level closes the pilot float orifice and increases the pressure in the pilot line; thus moving the piston and metering plug toward the closed position.

Flow in the pilot line is from the top of the 701S to the pilot float valve. On a 101 valve, the pilot line must be connected to the port toward the "tail" of the arrow cast in the 101 valve body. On a 301E valve, the pilot line may be connected to either of the valve inlet connections on the sides of the valve body. The pilot line must be 1/4" Nominal Pipe for proper operation (3/8" OD copper tubing is also acceptable for halocarbon applications). See the application diagrams for valve layouts.