AKV 20-3 (042H2024) Danfoss Electric Expansion Valve

Product Overview

The AKV 20-3 (042H2024) is a high-capacity, electronically operated expansion valve designed for precise liquid injection in large-scale refrigeration plants. Operating on the Pulse Width Modulation (PWM) principle, the Danfoss 042H2024 (042H2024) functions as both an expansion device and a solenoid valve, providing a tight shut-off when de-energized. This dual-purpose design is critical for B2B industrial applications such as cold storage warehouses, industrial chillers, and supermarket rack systems, where maintaining an exact superheat (SH) is essential for energy efficiency and compressor safety. The AKV 20-3 is engineered to handle higher mass flow rates than the AKV 20-1/2 models while maintaining rapid response times.

Technical Configuration

The AKV 20-3 utilizes a 13.5 mm actuator system and is typically driven by a Danfoss ADAP-KOOL controller. Instead of modulating the needle position, the valve cycles fully open and fully closed at high frequencies; the duration of the "open" phase determines the refrigerant flow. This mechanical simplicity allows for a robust, hermetic construction capable of withstanding millions of cycles. With a Maximum Working Pressure (PS) of 28 bar (406 psig), it is compatible with most HFC and HCFC refrigerants. The "Type 3" designation indicates a specific orifice capacity within the AKV 20 series, optimized for medium-to-high capacity evaporators.

Technical Specifications

Technical FAQs

How does PWM control differ from standard modulating expansion valves?

Standard valves move a needle in and out to restrict flow. PWM valves like the AKV 20-3 cycle between 0% and 100% open. This ensures that the refrigerant velocity is always high when the valve is open, which improves oil return and heat transfer efficiency in the evaporator.

Does this valve require an additional liquid line solenoid?

No. The AKV 20-3 is a Normally Closed (NC) valve that provides a reliable, tight seal when the power is removed. This eliminates the cost and pressure drop associated with an extra solenoid valve in the liquid line.

What is the expected service life of the orifice and needle?

The AKV series is designed for heavy industrial use. The internal components are made from high-grade materials to ensure a service life of over 50 million cycles, provided the system is kept clean and free of moisture.

Engineering & Installation Guide

• Upstream Filtration Requirements: It is mandatory to install a high-quality filter drier (such as the Danfoss DML or DCL series) immediately before the valve. Because the valve cycles rapidly, any metal shavings or debris in the liquid line can damage the valve seat or cause it to stick, leading to "flooding" or loss of superheat control.

• Brazing Thermal Protection: During the installation of the solder connections, the valve body must be protected from excessive heat. Wrap the body in a wet cloth and ensure that the temperature of the 13.5 mm actuator housing does not exceed 100 Celsius. Overheating will degrade the internal seals and the solenoid coil interface.

• Electrical Configuration: Ensure the coil voltage matches the output of your Danfoss AK-CC or AKC controller. The coil must be mounted with the cable entry pointing downwards to prevent moisture from traveling along the wire and into the actuator assembly (drip loop installation).