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Electronic Expansion Valve Throttling Air-Cooled Modular Unit

This air-cooled modular unit is designed for throttling with electronic expansion valves, where the valve opening is automatically adjusted based on system superheat to ensure variable refrigerant flow under different operating conditions. The system comprises two independent refrigeration circuits, each equipped with one scroll compressor (with options for either 1 or 2 compressors), two electronic expansion valves, two four-way reversing valves, and two condenser fans. The two circuits share a single plate-type (shell-and-tube) heat exchanger, and the condenser fans can operate in either single-fan mode or dual-fan modulating mode. Depending on the required cooling capacity, different addresses can be assigned, allowing up to 12 modules to be connected for multi-module operation. During multi-module operation, auxiliary electric heating and the chilled-water pump are controlled by the master module. The unit features an RS485 remote-control port supporting the Modbus protocol, enabling easy integration with other networked devices. Optional wired controls include the ST4HC and ST4LC models: the ST4HC offers touch-sensitive operation keys and a dot-matrix LCD display capable of showing four lines of eight Chinese characters or four lines of sixteen English characters; the ST4LC features a segment-display LCD with blue backlight, neutral-symbol keys, and broad compatibility. Digital input protection: 16 channels with opto-isolation, used for unit fault protection and interlock control, with a protected input voltage of DC 12 V. Digital output: 14 active outputs and 1 passive output, totaling 15 relay groups (for resistive loads at AC 220 V/5 A). Analog inputs: 11 channels for temperature measurement, plus 2 channels for 4-phase, 8-pulse electronic expansion valve control. Physical dimensions: ST4HC—165 mm × 115 mm × 30 mm (maximum overall size); ST4LC—109.80 mm × 64.80 mm × 20 mm; ST4GP—190 mm × 125 mm.

Category:

Air-cooled chilled (or heated) water modular unit

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sales@saturnchina.com

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Product Details

This air-cooled modular unit is designed for throttling in electronic expansion valve systems, where the valve opening is automatically adjusted based on system superheat to ensure appropriate refrigerant flow under varying operating conditions. The system comprises two independent refrigeration circuits, each equipped with one of two optional scroll compressors (1 or 2), two electronic expansion valves, two four-way reversing valves, and two condenser fans. The two refrigeration circuits share a single plate-type (shell-and-tube) heat exchanger, and the condenser fans can operate either in single-fan mode or in dual-fan modulating mode.

Depending on the required cooling capacity, different addresses can be configured, allowing up to 12 modules to be connected for multi-module operation. During multi-module operation, the auxiliary electric heating and chilled water pump are controlled by the master module.

Equipped with an RS485 remote control port and Modbus protocol, it can be easily integrated into other network devices.

Optional configurations include either the ST4HC or ST4LC wired remote control. The ST4HC features touch-sensitive operation buttons and a dot-matrix LCD that can display four lines of 8 Chinese characters or four lines of 16 English characters; the ST4LC is a segment-driven English LCD with blue backlight, neutral-symbol keys, and broad compatibility.

DI protection inputs: 16 channels, all opto-isolated, for unit fault protection and interlock control; protection input voltage: DC 12 V.

DO Outputs: 14 channels of powered outputs, 1 channel of unpowered output, for a total of 15 relay groups (resistive load, AC 220 V/5 A).

AI input: Channel 11 is an analog input type for temperature.

Two-channel, four-phase, eight-step electronic expansion output.

External dimensions:
ST4HC: 165 mm × 115 mm × 30 mm (maximum external dimensions)
ST4LC: 109.80 mm × 64.80 mm × 20 mm.
ST4GP: 190 mm × 125 mm.

Keywords: Electronic Expansion Valve Throttling Air-Cooled Modular Unit