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Products  |  Thermal Engineering and HVAC  |  Refrigeration and Air Conditioning Technology  |  ET 180
ET 180 Pressure Switches in Refrigeration Show data sheet (pdf file) Print page
Technical Description

  With this experimental unit the operation of the pressure switches, also called pressostats, used in refrigeration can be demonstrated.
  Pressure switches are used to protect the compressor and system components against too high or too low pressures. They are also used in the so-called pump-down circuits for the controlled shut-down of the compressor. Dependent on the application, individual pressure switches or combined pressure switches are used for high and low pressures.
  Both the pressure switches for monitoring the delivery pressure and for the intake pressure are available. The switching states are indicated by signal lamps. The switching thresholds and hystereses can be set by the trainee. This allows him to examine and understand the switching behaviour of the pressure switch. A typical refrigerant compressor generates the test pressures. Manometers indicate the pressures. Air is used as a pressure medium. The hazard-free operation of the pressure switches uses 24V.
  The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the exercises.

Learning Objectives / Experiments

- gain expert knowledge of refrigeration through

  practical exercises
- operation of a pressure switch
- difference between low and high pressure switches
- difference between NC and NO contacts of a switch
- setting the switching threshold
- setting the differential gap
- recording the switching behaviour of the pressure

  switch over pressure


* Gain expert knowledge of refrigeration through

  practical exercises1
* Checking and adjustment of pressure switches in

* Clear arrangement at the front panel1
* Display of switching states via lamps1
* Independent pressure generation via compressor


[1] experimental unit from the GUNT practical series for the training of mechatronics engineers for refrigeration
[2] operation and adjustment of pressure switches in refrigeration
[3] low pressure, high pressure and combined pressure switches
[4] indication of switching states via signal lamps
[5] pressure generation via independent refrigerant compressor, pressure medium air
[6] pressure adjustment via pressure keeping valve
[7] hazard-free operation of the pressure switches at 24V


Technical Data
Compressor pressure range: -0,9...24bar
Pressure switches adjustment range
- low pressure: -0,97,0bar
- hysteresis: 0,74,0bar
- high pressure: 8,032,0bar
- hysteresis: 410bar
Manometer measuring range
- low pressure: -1...9bar
- high pressure: -1...24bar
Dimensions and Weight
LxWxH: 1.000x650x530 mm
Weight: approx. 60kg
Required for Operation

230V, 50/60Hz, 1 phase or 120V, 60Hz, 1 phase

Scope of Delivery
1 experimental unit
1 set of instructional material
Order Details

061.18000  ET 180  Pressure Switches in


© 2005 G.U.N.T. Gerätebau GmbH