Series 3900 pressure switches are widely used in pilot duty applications and incorporate field adjustable set points and internal switch contacts. These switches convert a pressure signal to an electrical output. In response to a change in pressure, movement of an elastomeric diaphragm opens or closes an electrical circuit based on a predetermined pressure set point. The Series 3900 feature a compact size and a cost effective, combination terminal design which allows electrical connection with either 1/4" quick connect or #8 screw terminals. Pressure ranges as low as 6" Water Column (W.C.)* up to 5 PSI are available (1.5 kPa to 34.5 kPa). Series 3900 switches assure control stability through wide temperature and humidity conditions. As with all Tecmark® products, Series 3900 switches provide superior performance and uninterrupted service, even under extreme shock and vibration.

*27.7" water column = 1 PSI

Basic Construction

• Visual scale for adjusting pressure setting in the field
• Elastomeric diaphragm eliminates the need for an oil barrier
• Internal switch contacts
• A combination terminal design offers both 1/4" quick connect and #8 screw terminals
• Built in over pressure protection designed to eliminate stress on other critical operating components
• UL Recognized, CSA certified, as an operating, limit or safety control.
• SPST switching logic

Available Features

• Pressure ranges as low as 6" WC up to 5 PSI (1.5 kPa to 34.5 kPa)
• Factory calibration available upon request
• A variety of mounting pan and pressure fitting materials; plated steel, stainless steel or injection molded plastic
• Wide array of pressure fittings; 1/8" NPT male, 1/4" NPT male, 3/16" barbed, 1/8", 3/16" or 1/4" compression, or 1/8" NPT female with 1/2" conduit male external thread for mounting
• Specialty diaphragm materials; Buna-N, EPDM, Hydrin
• Models available with or without wiring enclosures

Ratings and Specifications

• Maximum Operating Pressure and Hydrostatic burst pressure, varies based on model configurations. Consult factory for specific application needs.
• ELECTRICAL Resistive rating: 15 amps @ 6 V.DC.
• 8 amps @ 12 V.DC.
• 4 amps @ 24 V.DC.
• Inductive rating: 1 amp @ 120 VAC
• Pilot Duty: 72 VA pilot duty @ 24 VAC
• 120 VA pilot duty @ 120 VAC
• 240 VA pilot duty @ 240 VAC
• Field tested critical components specifically selected to operate reliably in temperature extremes of 32° to 190°F (0°C to 88°C)
• 100,000+ cycle life under full mechanical, electrical and thermal loads