This heavy duty solenoid valve is suitable for Ammonia, R-12, R-22, and R-502, other refrigerants, certain oils and other fluids approved for use in refrigeration. The S4A is a pilot operated, semi-steel bodied valve. The valve may be opened by means of the manual opening stem for servicing or in case of electrical power failure.
The Type S4A Solenoid Valve is furnished with FPT Internal NPT (U.S. Standard Taper Pipe Thread), Socket Weld, Weld Neck or ODS (solders over copper tubing of given diameter) connections. The valve may be easily removed from between the flanges for servicing.
- Standard Coil Housing Meets NEMA 3R and NEMA 4-Rain Tight
- Coil Housing Surpasses NEMA Salt Spray Test
- Plunger-Needle Assembly Same for S4A,S5A,S6N,S6A,S8F
- Molded Class “B” Coil Construction
- Same Coil Fits Most Refrigerating Specialties Solenoid Valves
- Pilot Light Available
- Stainless Steel Needle
- Manual Opening Stem
- Design Pressure (MRP): 28 bar (400 PSIG)
It is advisable to install a strainer upstream of each valve to prevent entrance of foreign material into the valve and the rest of the system. Refrigerating Specialties strainers are available to close-couple to valve inlets.
Type S4A is a spring closing valve, suitable for use in refrigerant liquid, hot gas or suction lines in a temperature range of -50° to 105°C (-60° to 220°F).
Principles of Operation
The Type S4A is a pilot operated solenoid. The valve in its closed position, with the solenoid coil de-energized and the plunger needle and main port plug in the seated position, is shown in Figure 1. Electrical energization of the solenoid coil forms a magnetic field, pulling up the plunger which strikes the needle, lifting it off its seat. Upward motion of the needle permits entrance of the fluid from the valve inlet M through Port N and down through the pilot port to the top of the power piston. This forces the piston downward and pushes the main port plug open, thereby permitting flow of the refrigerant through the valve. The closing spring meanwhile is held in a compressed position.
De-energization of the solenoid coil permits the spring-assisted needle to drop back into its seat, stopping the flow through the pilot port. Bleed-off, through the bleed hole in the piston, decreases the pressure above the piston and allows the closing spring to force the main port plug upward into a closed position to stop the flow. The pressure difference across the valve, acting upon the area of the valve seat, plus the force of the closing spring, holds the main port plug in a tightly closed position.
Manual Opening Stem
The manual opening stem on the Type S4A is for the purpose of opening the valve without energizing the solenoid coil. Refer to the applicable exploded view and parts list for location of the stem and other related parts. For access to stem the seal cap on the bottom of the valve must be removed. This must be done with caution as refrigerant may have been trapped inside the seal cap. To open the valve manually, turn the stem counterclockwise as far as it goes. To reset for automatic operation turn the stem clockwise until only the flats on the end of the stem protrude from the packing nut.