The CUBO2 AQUA is a high-efficiency condensing unit designed for transcritical CO2 applications, featuring a BLDC variable speed compressor. Its compact design and ease of installation allow for direct communication with refrigerated units. This ensures highly efficient operation, even at partial loads, without compromising food preservation. This manual specifically refers to CUBO2 AQUA models intended for cooling and conservation at low temperatures, identified by models such as UMT/WG T 030 BT DX, UMT/WG T 045 BT DX, UMT/WG T 067 BT DX, and UMT/WG T 100 BT DX.

Function Description:

The unit operates as a booster system with two BLDC compressors of the same size. One compressor manages the evaporation pressure control for low-temperature refrigerated devices, while the other (PARALLEL) controls the pressure in the receiver. No flash valve is installed in this unit. The system maintains specific pressure ranges: Parallel Compressor discharge pressure (PGC) operates between 45-105 bar, Parallel Compressor suction pressure/Receiver pressure (PREC) between 32-60 bar, and LT suction pressure between 12-18 bar. The compressor modulation range is 25-100 rps. The cooling of discharge gas occurs in a Gas-Water heat exchanger (PHE), with water flow controlled by a 3-Way Modulating Valve based on the Gas Cooler outlet temperature. The unit is managed by a Carel prackCO2 HECU controller, which optimizes working parameters, including BT compressor suction pressure, 3-way valve modulation for gas cooler outlet temperature, gas cooler pressure for optimal COP, and receiver pressure with a floating set-point (32-38 bar). All alarms related to compressor and pressure levels are monitored.

Important Technical Specifications:

The CUBO2 AQUA units use R744 (CO2) as refrigerant. Compressor types vary by model: UMT/WG T 030 BT DX and UMT/WG T 045 BT DX use 1x Toshiba DY30N1F-10FU - BT and 1x Toshiba DY30N1F-10FU - Paral. or 1x Toshiba DY45N1F-10FU BT and 1x Toshiba DY45N1F-10FU Paral. respectively. UMT/WG T 067 BT DX and UMT/WG T 100 BT DX use 1x Toshiba DY67L1F-10FU - BT and 1x DY67L1F-10FU - Paral. or 1x RY100L1F - BT and 1x DY100L1F - Paral. respectively. All compressors are rotary type with 4 poles and DC Brushless motor type, operating at 25-100 rps. Oil charge per rotary compressor is 520 ml for 030/045 models and 450 ml for 067/100 models, using PAG VG100 oil. Discharge pressure is max 125 bar, and suction pressure is 12-41 bar. Evaporating temperature range is -30°C to -20°C, with suction superheating of 10K-20K. Max discharge temperature is 130°C. Ambient temperature range is -15°C to +43°C (-20°C with winter kit option). Water inlet temperature is +7°C to +37°C. The liquid receiver volume is 8 liters, with a maximum permitted CO2 charge of 7.2 kg in pump-down condition. Suction and liquid line connections are 3/8" K65 (9.52mm) for 030/045/067 models, and 1/2" K65 (12.7mm) for suction line and 3/8" K65 (9.52mm) for liquid line on 100 models. PS Suction/Liquid is 80 bar/80 bar. The unit falls under PED Category II. Dimensions are 1545 x 570 x 805 mm (A x B x H), with a net weight of 176 kg and gross weight of 194 kg. Sound level (max speed) is 41 dBA for 030/045 models and 42 dBA for 067/100 models. Electrical power supply is 230V/1Ph+N+PE/50Hz for 030/045 models and 400V/3Ph+N+PE/50Hz for 067/100 models. Recommended protection is a circuit breaker C 16A (030), C 25A (045/067), and C 20A (100). Maximum Rated Amps (MRA) are 13.9A (030), 20.7A (045), 20.4A (067), and 19.9A (100). Max absolute power is 3190W (030), 4760W (045), 7065W (067), and 9590W (100).

Usage Features:

The unit is designed for outdoor installation, requiring specific minimum distances for proper operation and maintenance. For multi-split layouts, a dedicated suction line for each evaporator is collected by a manifold near the condensing unit. SCM Frigo recommends connecting up to 3 remote evaporators with a maximum suction pipe length of 20 meters per evaporator. Proper sizing of liquid and suction lines is crucial for good oil return and low pressure drop. The user interface allows for easy control and monitoring, including ON/OFF unit control, regulation set point adjustment, and configuration of MPXPRO and ULTRACELLA/EVO CAREL controllers for evaporator communication. A "VACUUM" software function is available to automatically open HPV and compressor equalization solenoid valves for evacuation. Refrigerant charging requires CO2 of purity class N4.0 or comparable, with moisture content <10 ppm. Liquid CO2 should only be charged from the liquid line, and CO2 gas from the suction line. Overcharging the system is strictly prohibited to prevent compressor damage.

Maintenance Features:

Annual checks are recommended, including inspection of the compressor and inverter for unusual sounds, vibrations, excessive temperature, electrical terminal tightness, and bolting to the base. Compressor running current should be within data, and oil topped up if necessary. Pressure vessels require inspection for damage, corrosion, and leaks as per local laws. The liquid drier filter should be replaced every 2 years, checking for temperature drop across it. High pressure switches must be tested for correct cut-out and reset. Pressure relief valves (PRVs) must be checked for tightness and replaced as per manufacturer guidelines. Procedures for PRV replacement are detailed, including options for single PRV valves or two PRVs connected via a changeover valve for quicker replacement. Unit operation should be checked for controller, valve, or sensor faults, and alarm logs consulted for present and past alarms. A general inspection should include a full system leak test, repair of missing/broken insulation, checking functionality of electrical components and anti-vibration mounts, and ensuring all pipework, supports, valve caps, and electrical guards are present. The HECU controller layout and terminal block connections are provided for electrical maintenance.

SCM Cuno 2 Aqua - Page 44

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