Pressure switches

Pressure switches: reliable control for HVAC and industrial processes

Pressure switches (pressostats) are essential automation components that ensure precise pressure control of liquids and gases and protection of systems. They protect equipment from dangerous pressure surges or, conversely, act as reliable dry-run protection when the flow pressure drops critically.

Danfoss pressure switches: precise series segmentation

• KP1 / KP2 / KP5 / KP7: Designed for refrigeration and HVAC systems. An ideal choice for low and medium pressure control.
• KPI35 / KPI36: Industrial switches adapted for working with liquids and gases. Widely used for general control functions of heat substation equipment.
• KPS35 / KPS36: Heavy-duty pressostats adapted to particularly harsh industrial conditions (IP66, ATEX standard).
• RT series: Universal industrial control devices with an extremely robust construction.

Compact and robust alternatives: Alco (Emerson) and Ranco

Alco (Emerson) pressure switches stand out for their extremely compact design, so they are perfectly suited to HVAC installations with space constraints. Ranco pressostats, meanwhile, are valued as extremely robust alternatives that withstand heavy loads.

Differential pressure switches

For systems where it is important to monitor not the absolute but the differential pressure, specialised switches are used, such as the Danfoss MP54, MP55A or RT differential models. These devices are especially important for monitoring compressor oil pressure and for flow control of pumps.

How to select a pressure switch correctly?

• Range and differential (hysteresis): Assess within which pressure limits the contact must operate and reset.
• Contact type (SPDT vs SPST): SPDT contacts make it possible to control the system and activate an emergency alarm at the same time.
• Vibration resistance: When installing the device directly on a running compressor or pump, high vibration resistance is required.
• Reset type (Auto-reset vs Manual reset): For critical safety applications (e.g. together with safety valves) manual reset is mandatory.

Frequently asked questions (FAQ)

• How does a pressure switch differ from a pressure transmitter?
  A pressure switch is an electromechanical device (On/Off principle, pump protection). A pressure transmitter measures pressure continuously and sends an analogue signal (4-20 mA).
• When is "Manual reset" necessary?
  This reset type is mandatory in all emergency protection systems - it forces technical staff to check and eliminate the cause of the fault before restarting the system.

Looking for reliable components for your heat units or make-up lines? Contact the Amegata.lt specialists - we will help you select the optimal switches for pressure control.