Danfoss CS Data sheet

Data Sheet

Pressure switch
Type CS

For air compressors and water boosters

CS pressure switches have a built-in pressure
operated, three-pole switch. The contact
position of which depends on the pressure in
the connector and the range setting and
adjustable dierential.

The pressure switches are tted with a manual
switch that will lock the contact system in the
open position independently of the pressure in
the system. Pressure switches with relief valve is
used in compressed air systems where pressure
relief on the compressor piston before start is
required.

The CS is suited for automatic start and stop of
air compressors and water boosters.

Features:

• Pressure ranges 2 – 20 bar

• Pressure connection G ½ or G ¼

• Contact system 3-pole (TPST) as standard
available also as an accessory

• Adjustable dierential

• Relief valve as accessory

• Manual switch to lock the contact system

• Enclosure IP43 or IP55

• Special versions with pressure connection
made of polyacetal suitable in drinking water
applications

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Danfoss

31E58

Slide ring

Earth screw

Cover screw

Cover

Spindle

Toggle arm

Snap spring

Snap arm

Switch housing assy

Self-tapping screw

Manual switch

Base

Grubscrew

Stop pressure screw

Pressure pad

Spring retainer

Compression spring

Pressure shoe

Diaphragm

Flange, G ¼ or G ½

Cap

Dierential arm

Tension spring

Dierential pressure screw

Bracket

Pressure switch, Type CS

Function

Figure 1: Design and function

The pressure switch is built up of the following main elements: connector, diaphragm, snap system, main spring,
dierential spring and a 3-pole or one-pole contact system. The stop pressure must be set on the main spring and
the dierence between start and stop pressures on the dierential spring.

Pressure from the controlled system is led, via the connector, to the diaphragm. The diaphragm converts this
pressure to a mechanical movement which is transferred by the snap system to the contact system. In this way, the
contact system starts or stops a compressor/pump.

© Danfoss | Climate Solutions | 2021.03 AI239086444789en-000701 | 2

A

Example 1

Control of an air compressor with a CS pressure
switch.

Example 2

Control of a compressor with a CS pressure switch
tted with pressure relief valve. Note the check valve
between pressure relief line and reservoir.

Example 3

Control of an air compressor with a CS. An EV210B 3B
solenoid valve is recommended where there is need
for especially fast pressure relief.

CS

Danfoss

31E22

CS

A

Danfoss

31E27

CS

A

Example 4

Control of a centrifugal pump with a CS, via an
automatic star-delta switch, motor starter, or similar.

Example 5

Pressure boosting system for domestic circuits. A type
CS switch is used to start/stop the pump.

CS

A

Danfoss

31E56

Motor starter or automatic start-delta switch

Pressure switch, Type CS

Application

Table 1: Application examples

© Danfoss | Climate Solutions | 2021.03 AI239086444789en-000701 | 3