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Weksler Pressure & Temperature Switches

A division of Ashcroft Inc., Weksler has set the standard worldwide for accuracy, quality and dependability.  Weksler manufactures an extensive line of pressure gauges.

Considerations in Selecting a Weksler Switch

Before selecting a Weksler temperature or pressure switch, consider the following:

1. Actuator

The actuator responds to changes in pressure, temperature or differential pressure and operates the switch element in response to these changes.

The actuator is normally exposed to process fluid and must therefore be chemically compatible with it. The following may be used to help select actuator type:

For nominal pressure ranges 0-15 psi through 0-3000 psi, the standard Weksler actuator is a diaphragm-sealed piston. In this actuator, process pressure acting on the piston area causes it to overcome the adjustment spring force and actuate a snap-action switch. A diaphragm and O-ring seal the process media from this mechanism. These are available in various materials, i.e.: Buna N, Teflon and Viton. The standard process connection is stainless steel. Optional monel pressure connection is available.

For H2O pressure and differential pressure ranges, a diaphragm actuator is used. In this design, the standard pressure connections are carbon steel. Diaphragms are available in Viton, Buna N and Teflon. Always review process temperature limits before making seal selections. Optional stainless steel pressure connections are available (option XTA).

For high differential pressure ranges, 3-15 to 60-600 psid, a dual diaphragm-sealed piston actuator is used. This actuator is designed for high static-pressure applications. The standard pressure connections are nickel-plated brass. Weksler diaphragms are available in Viton, Buna N and Teflon. Always review process temperature limits before making seal selections. Optional stainless steel pressure connections are available (option XUD).

For all temperature ranges, the standard Weksler temperature actuator operates on the vapor pressure principle: the vapor pressure in a sealed thermal system is applied to a sensing element, which in turn actuates a switch. This is known as a SAMA Class II system. Various filling materials are used, including propane, butane, methyl alcohol, n-propyl alcohol and xylene. High overtemperature capability is possible with this type of system. The interface between liquid and vapor is the point at which sensing occurs. This is the “sensitive” portion of the bulb. Weksler bulb extensions and capillary are normally filled with vapor, and have little effect on the setpoint, regardless of ambient temperature variations; therefore, no ambient compensation is required. For best results, the bulb should be mounted within 60 degrees of vertical to assure the liquid remains in the bulb.

2. Enclosure

The enclosure protects the switch element and mechanism from the environment and has provisions for mounting and wiring. All Weksler switch enclosures are epoxy-coated aluminum or stainless steel for maximum corrosion resistance. Choose between watertight NEMA 4, 4X for most industrial applications and explosion-proof NEMA 7/9 for most process applications.

Weksler enclosures include watertight cover gaskets, external mounting holes and one or two 3/4 NPT electrical conduit holes for ease of installation. Weksler pressure switches may also be mounted directly to the process by means of the standard 1/4 NPTF or optional 1/2 NPT pressure connection.

Note: When installing Weksler switches, refer to instruction sheets included with each switch, the National Electrical Code, and any other local codes or requirements to assure safety.

3. The Switching Function

Next, consider the switching function. Most applications for alarm and shutdown are satisfied by single setpoint, fixed deadband models. For high/low or alarm and shutdown, the dual setpoint Weksler models may be selected. For pump, compressor, level and other control applications, an adjustable deadband Weksler model is often the best choice.

4. The Switch Element

Finally, the electrical switching element must be compatible with the electrical load being switched. For ease of selection, all Weksler electrical switching elements are snap acting, SPDT (single pole-double throw), or 2 (SPDT). Refer to Weksler catalog pages for switch element choices. Select a switch element with electrical rating that exceeds the electrical rating of the device being controlled by the switch. For better reliability and safety, optional Hermetically Sealed Weksler switching elements may be specified.

To start, please select a basic type of Weksler switch

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