Carrier 30GH 040 - User Manual

The Carrier 30GH 040-245 and 30GZ 040-245 are air-cooled liquid chillers designed for various applications, including air conditioning, industrial process cooling, and low-temperature operation. These units are built to provide efficient cooling and are suitable for outdoor installation. They operate on a 50 Hz power supply and are equipped with the REGULATION PRO-DIALOG PLUS control system, ensuring precise and stable operation.

Function Description

The primary function of these chillers is to cool a liquid (typically water or brine) which is then circulated through a system to provide cooling. The units utilize a refrigeration circuit that includes compressors, an evaporator, and a condenser. The compressors, which are semi-hermetic with 4 or 6 cylinders, compress the refrigerant. The evaporator then transfers heat from the liquid to be chilled to the refrigerant, causing the liquid to cool down. The heated refrigerant then moves to the condenser, where it releases heat to the ambient air, facilitated by axial fans. The cooled refrigerant then returns to the evaporator to repeat the cycle.

The chillers are designed with either one or two refrigeration circuits, depending on the model, to enhance reliability and efficiency. The control system manages the capacity stages, optimizing performance based on the cooling demand. For models 30GH/GZ 170-245, there are two power connection points, indicating a larger capacity and potentially dual power feeds for enhanced operational stability.

Safety is a key aspect of the design, with various protection devices integrated into the system. High-pressure switches, low-pressure protection, and defrost protection mechanisms are in place to prevent damage and ensure safe operation. Compressor protection is handled by a dedicated circuit board (STARTERGUARD) that monitors the compressor's operating environment, including crankcase heaters, contactors, and control wiring. This board uses LED indicators to display the status of controlled components and will shut down the compressor if a fault is detected.

Usage Features

The chillers are designed for ease of use and integration into existing systems. Water connections are made via flat flanges, and the units are equipped with drain valves at low points and air purge valves at high points to facilitate maintenance and prevent issues like freezing. It is crucial to ensure proper water flow rates within the specified minimum and maximum values to maintain optimal performance and prevent evaporator damage. For stable operation and accurate temperature control, a minimum water loop volume is required, which may necessitate the addition of a buffer water reservoir.

The control system allows for precise temperature regulation, making these units adaptable to different cooling requirements. For installations where water temperatures below 5°C (for R-407C) or 4°C (for R-22) are likely, the addition of ethylene glycol is recommended to prevent freezing. The units are designed for outdoor use, but considerations for heavy snowfall or strong winds may require additional measures like raising the unit or installing baffles to ensure proper airflow and prevent snow accumulation.

The compressors are mounted on anti-vibration mountings to minimize noise and vibration during operation. For larger units (30GH/GZ 085-245), shipping wedges and retaining bolts must be removed during installation to allow these mountings to function correctly. The fan rotation is counter-clockwise when viewed from above, ensuring efficient air circulation through the condenser coils.

Maintenance Features

Regular maintenance is essential to ensure the longevity and efficient operation of the Carrier chillers. The manual provides detailed instructions for various maintenance tasks, emphasizing that only trained and qualified refrigeration engineers should perform installation, start-up, and servicing due to the inherent hazards of system pressures and electrical components.

Key maintenance aspects include:

General Maintenance: Keeping the unit and its surroundings clean, free of obstructions, and regularly cleaning exposed pipework to detect water leaks early. All screwed and bolted connections should be checked for tightness to prevent leaks and vibrations. Insulation joints and heat exchangers also require regular inspection.
Refrigerant Charge: The units are shipped with a full normal charge of refrigerant. Regular checks for refrigerant leaks are crucial, especially for R-407C units, as leaks can alter the composition of the refrigerant blend. If recharging is necessary, it must be done in the liquid phase at the liquid line, and a purpose-built refrigerant recovery unit should be used to minimize discharge to the atmosphere.
Compressor Oil Charge: The oil level in each compressor sight glass should be checked and maintained between 1/8 and 3/8 of the total glass depth when the compressor is running normally. Only approved refrigeration oils should be used.
Crankcase Heaters: These heaters prevent refrigerant absorption by the compressor lubricating oil when the compressor is shut down. They must be energized for at least 24 hours before restarting the unit after a shutdown. Regular checks ensure their correct operation.
Evaporator Maintenance: This involves checking the insulating foam, cooler heaters, and water-side connections for cleanliness and leaks. If a tube in the evaporator develops a leak, it can be plugged, but replacement by a trained service engineer is recommended. When rebuilding the cooler, new gaskets conforming to Carrier specifications must be used, and cooler head bolts must be tightened in a specific sequence to the correct torque.
Condenser Coil Cleaning: Finned coils should be regularly inspected for fouling, especially in urban or industrial environments. Cleaning involves removing dust and fibers with a soft brush or vacuum cleaner, followed by cleaning with appropriate agents. Pressurized water should be used with caution and a large diffuser to avoid damaging the coil fins.
Fan Motor Replacement: Instructions are provided for replacing fan motors, emphasizing careful handling and maintaining specific clearances during installation.
Filter-Drier: The filter-drier keeps the circuit clean and dry. The sight glass indicates when the cartridge needs changing, and a temperature difference between the inlet and outlet of the filter-drier suggests fouling.
Troubleshooting: A comprehensive troubleshooting chart is provided to help identify possible faults, their causes, and suggested remedies, covering issues like the unit not starting, continuous operation, compressor cut-outs, noises, and oil or water losses.

Before any work on the machine, it is imperative to ensure that the power supply is switched off and locked out, and all isolators are tagged. If a refrigerant circuit is opened, it must be evacuated, recharged, and tested for leaks, and the filter-drier must be changed.