Danfoss STF, STF-H Data sheet

Data Sheet

4-Way Reversing valves Type STF and STF-H

The 4-way valves are used in reversible applications such as heat pumps or reversible air conditioning units and chillers.

The 4-way valve allows an inversion of the refrigeration cycle, changing from cooling mode in summer to heating mode in winter.

Features

• Wide application range

◦ complete capacity range ◦ available for all common refrigerants

including ammable refrigerants)

◦ many dierent connection diameters and

congurations

• High reliability

◦ unique design ◦ instantaneous changeover at minimum

pressure dierential

◦ mechanism to prevent incomplete

changeover

◦ Minimized leakage

• CE approved

AI356550649035en-000101en-000201

4-Way Reversing valves, Type STF and STF-H

Application

The cycle inversion is initiated by a small solenoid pilot valve, which pilots the movement of a slider, which changes the direction of the refrigerant. The valve is connected to the discharge and suction pipes.

The pilot valve ensures a very reliable changeover from cooling to heating mode, the changeover happens instantaneously with a minimum pressure dierential. The valve design also guarantees a minimum pressure drop and a very low risk of leakage.

Figure 1: HEATING CYCLE (Coil energized) Figure 2: COOLING CYCLE (Coil not energized)

Danfoss

80Z930

123456Discharge connection

Connection to evaporator/ condenser

Suction connection

Connection to condensor/ evaporator

Valve body

Slider

Parameter

STF and STF-H

Compatibility refrigerants

R22, R134a, R407A, R4070, R404A, R410A, R448A, R449A R32, R290, R454C, R454B, R452B (see safety note below)

Min. OPD

3 bar

Max. OPD

31 bar

Max. working pressure (PS/MWP)

45 bar Note! 49 bar for selected models. Please check Table 2: Ordering table for further information.

Refrigerant temperature range

–30 to 130 °C Note! 160 °C for selected models. Please check Table 2: Ordering table for further information.

Ambient temperature

–30 to 55 °C

4-Way Reversing valves, Type STF and STF-H

Product specication

Technical data

Table 1: Technical data

NOTE:



Special safety note for ammable refrigerants!

For countries where safety standards are not an indispensable part of the safety system Danfoss recommends the installer gets a third party approval of any system containing ammable refrigerant

Please refer to separate drawings of the STF and STF-H valves with special disclaimer regarding usage of ammable refrigerants. Please refer to separate document “Important Notice for usage of STF and STF-H valves with ammable refrigerants (No. S-FD001-1).

Design

Figure 3: Design

The valve is composed of three basic components:

• Pilot valve

• Main valve body, including valve slider

• Solenoid coil

4-Way Reversing valves, Type STF and STF-H

The 4-way valve slider is shifted by changes in dierential pressure in the valve which is actuated by the pilot solenoid valve. The valve slider is specially designed to prevent incomplete changeover and movement with minimum pressure dierential.

Dimension

Refer to separate drawings of models. - Contact danfoss for further information.

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