The Marstair CKC Condensing Units are designed for refrigeration and specialist air conditioning applications, serving as the outdoor component of a split system. These units are supplied with a holding charge of oxygen-free nitrogen and polyolester oil, and are not fitted with an expansion device. They contain live electrical components, moving parts, and refrigerant under pressure, necessitating careful siting away from children and protection from vandalism.
Function Description:
The CKC Condensing Units are responsible for rejecting heat from the refrigeration cycle to the ambient air. They work in conjunction with an indoor unit (not included in this manual) to provide cooling. The units are available in both single-phase (1ph) and three-phase (3ph) configurations, catering to a wide range of cooling capacities from 2.5 kW to 19.9 kW. Key components include a compressor, condenser coil, and fan motor(s), all housed within a protective cabinet.
Important Technical Specifications:
Cooling Capacity:
- CKC 15: 2.5 kW
- CKC 20: 2.8 kW
- CKC 30: 3.7 kW
- CKC 40: 4.2 kW
- CKC 50: 5.8 kW
- CKC 60: 7.0 kW
- CKC 80: 7.4 kW
- CKC 90: 8.2 kW
- CKC 100: 10.9 kW
- CKC 130: 12.4 kW
- CKC 150: 13.9 kW
- CKC 165: 14.7 kW
- CKC 180: 17.1 kW
- CKC 200: 19.9 kW
Operating Weight (Unpacked):
- 1ph units range from 45 kg (CKC 15) to 76 kg (CKC 90).
- 3ph units range from 48 kg (CKC 30) to 173 kg (CKC 200).
Electrical Specifications (Nominal):
- 1ph (230V 50Hz):
- Power: 1.1 kW (CKC 15) to 4.2 kW (CKC 90).
- Starting Current (LRA): 23 A (CKC 15) to 114 A (CKC 90).
- Nominal Current (FLA): 5.9 A (CKC 15) to 16.9 A (CKC 90).
- 3ph (400V 50Hz):
- Power: 1.6 kW (CKC 30) to 9.4 kW (CKC 200).
- Starting Current (LRA): 18 A (CKC 30) to 98 A (CKC 200).
- Nominal Current (FLA): 3.6 A (CKC 30) to 16.9 A (CKC 200).
Condenser Fan (1ph 230V 50Hz):
- Airflow (max speed): 0.97 m³/s (single fan) or 1.85 m³/s (twin fan).
- Fan motor rating: 0.13 kW (single fan) or 2x0.13 kW / 2x0.24 kW (twin fan).
- Nominal current (FLA): 0.6 A (single fan) or 2x0.60 A / 2x1.00 A (twin fan).
- Fans: 1x457mm or 1x508mm (single fan), 2x457mm or 2x508mm (twin fan).
- Max speed: 760 rpm to 950 rpm.
Sound Pressure Levels (SPL) at 10m:
- Range from 38.7 dBA to 43.2 dBA, depending on the model.
Refrigerant:
- R407C is the specified refrigerant. It must always be added in the liquid state.
- The system should not be overcharged to avoid liquid return to the compressor.
Dimensions (mm) and Weights (kg) - Unpacked:
- CKC 15-40: Height 620, Width 900, Depth 300. Weights 45-53 kg (1ph).
- CKC 50-80: Height 720, Width 1000, Depth 350. Weights 64-66 kg (1ph), 62-64 kg (3ph).
- CKC 90-100: Height 820, Width 1000, Depth 350. Weights 76 kg (1ph), 73-81 kg (3ph).
- CKC 130-165: Height 1080, Width 1000, Depth 425. Weights 101-103 kg (3ph).
- CKC 180-200: Height 1275, Width 1100, Depth 425. Weights 118-173 kg (3ph).
Pipe Sizes (outside diameter in inches):
- Expansion Line: 3/8" (CKC 15-60), 1/2" (CKC 80-200).
- Suction Line: 3/8" (CKC 15-20), 1/2" (CKC 30-50), 5/8" (CKC 60-80), 3/4" (CKC 90-165), 7/8" (CKC 180-200, brazed connections).
Restrictors:
- Outdoor units (cool only) have optional kit expansion assemblies with cooling restrictors fitted. Restrictor sizes range from 0.033 (CKC 15-20) to 0.082 (CKC 165). CKC 180-200 are N/A for restrictors.
Usage Features:
Installation and Mounting:
- Units are designed for flat surface mounting. Wall mount brackets are available as optional kits (CKC 15-80: 55021100; CKC 90-200: 55021101).
- Adequate space for air circulation and maintenance access is crucial (100mm minimum on sides, 600mm above, 1500mm air off).
- The mounting surface must support the unit's weight.
- Easy access for installation and service is a standard feature.
Pipework Connection:
- Units feature suction and liquid service valves.
- Flare connections are used for most models, with CKC 180 & 200 having 7/8" suction pipes with brazed connections.
- Maximum pipe runs: 45m for liquid lines (20m for CKC 15-20), 80m for expansion lines (50m for CKC 15-20), including lifts.
- Good practice includes keeping pipe runs short, avoiding sharp bends, fully insulating pipes, and forming oil traps in vertical risers exceeding 3m.
Electrical Connection:
- Mains, control, and interconnecting cables are supplied by the installer and must comply with local/national codes.
- Units must be earthed.
- Interconnecting wiring diagrams are found in the indoor unit instructions.
- For 3ph scroll compressors (CKC 50-200), incorrect phase rotation can cause the compressor to run backward; this is corrected by exchanging two supply phases.
- Isolator switches for 3ph systems require a neutral contact that is an early make, late break type to prevent damage to the electronic board.
Refrigerant Charging:
- The system must be evacuated to 1000 microns (1 Torr) or better and held for at least 15 minutes.
- Refrigerant is added through the Schrader valve on the suction service valve.
- The final charge is adjusted with the system running.
- Units are fitted with head pressure control; a link wire across orange terminals allows the fan to operate at full speed and must be removed after charging.
- A random start delay of up to 1 minute occurs when mains is first applied, followed by a 3-minute delay between successive compressor operations.
Head Pressure Control (ALCO FSY-42S):
- Factory set for the refrigerant, but may require adjustment for site conditions.
- Adjustment involves connecting a high-pressure gauge, running the system, and turning a 2mm or 5/64" Allen key in the setting screw (clockwise for +2.5 bar/turn, counter-clockwise for -2.5 bar/turn). Do not exceed 3 turns clockwise.
- Min fan speed (0 rpm) and fan cut-in pressure (200 psig / 13.8 barg) are factory set and non-adjustable.
Maintenance Features:
Component Identification:
- Detailed diagrams are provided for CKC 15-100 and CKC 130-200 models, identifying all major components such as the compressor, condenser coil, fan motor, service valves, electrical box, and control PCBs. This aids in troubleshooting and part replacement.
Cleaning and Service Access:
- Easy access for installation and service is a standard feature, facilitating maintenance tasks.
- If an expansion assembly requires cleaning, it can be removed, split, and the restrictor accessed.
End of Life Requirements:
- Refrigerant must be recovered by a certified technician, with modern recovery machines capable of removing over 95% of the refrigerant.
- Recovered HFC refrigerants can be sent for destruction, re-processed into "reclaimed refrigerant," or given basic cleaning to create "recycled refrigerant."
- Reclamation is encouraged due to potential HFC supply shortages. Mixing different gases in recovery cylinders is strictly prohibited.
- Reclaimed refrigerant can be used in any refrigeration equipment. Recycled refrigerant must be used with care due to potential contamination. Use of recycled refrigerant with GWP above 2,500 is restricted to the original owner or recovery organization.
General Safety and Best Practices:
- Personnel working on this equipment should be skilled and conversant with appropriate Air Conditioning, Refrigeration, and Electrical practices, and have sound knowledge of current Industrial Safe Working practices.
- Do not mix oils or refrigerants.
- The data plate provides information for the outdoor unit only; system details require adding input power and current of indoor and outdoor units, including any heater load.
- Fuses: Recommended fuse sizes are provided for both 1ph and 3ph units, ranging from 10A to 32A.
- After installation, check all pipework and joints for leakage, ensure pipework and fittings are insulated, and verify that all fasteners are secure and the fan rotates freely.
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