China Good quality CHINAMFG Air Cooled Rooftop Packaged Units Scroll/Piston/Screw Compressor air compressor parts

Product Description

Company Profile
SENDO is a professional manufacturer of quality air conditioning products.
Sendo could supply most products in CHINAMFG field, such as Rooftop Packaged Unit, Split Commercial Unit, Air Cooled Water Chiller, Water Cooled Water Chiller, Chilled Water Air Handling Unit and Fan Coil Unit etc. CHINAMFG also supplies made-to-measure CHINAMFG solutions. We engineer and manufacture Air Conditioner to suit the building design and application.

Rooftop Packaged Unit


1. Convenient for unit selection

– Colour selection
The color can be ordered (OEM) in either white or grey.

– Wide cooling capacity range
There is a large production line of packaged units, with capacities ranging from 3Ton to 110Ton (12kW to 392kW) at nominal conditions.

– Panels selection
Panels can be constructed of galvanized steel coated (Standard) or Panels are double-skin with injection of high density polyurethane.

– Optional accessories
• Inverter Scroll compressors
• EC Plug-Fans
• Tropical climate T3 condition
• Economizer/Free cooling with return air, fresh air dampers and fresh air hood
• Heat recovery (Plate type heat recovery & Wheel type heat recovery optional)
• Additional water heating coil or electric heater for heating or dehumidification
• Optional supply / return air configuration (Side/Top/Bottom)
• Optional high level filter (G4 panel type filter, F8 bag type filer and H13 HEPA filter etc)
• Optional CHINAMFG condenser & evaporator for some area need special anti-corrosion
• Optional precision temperature & humidity control
• 100% Full fresh air
• High external pressure, long air supply distance

2. Outstanding reliability

– Economy
Some models feature the flexibility and economy of 2~4 stages operation. Compressors are progressively switched on only as they are needed. This has the added advantage of lowering start-up current.

– Durable construction
• Standard cabinets are constructed from high grade galvanized steel with polyester powder coated, they are completely weatherized for outdoor installation.
• Coils are manufactured from seamless copper tubes mechanically expanded into hydrophilic aluminum fins, they are tested under 450 CHINAMFG at the factory to avoid leakage. They also undergo dry chemical cleaning after manufacturing for optimum system cleanness.
• External fasteners are stainless steel or galvanized type. Corrosion resistant drain trays are also included.
• All units are tested at the factory to make sure no leakage and provide reliable start up.

– Reliable scroll compressor
High efficiency scroll compressor for the whole range, with built-in thermal overload cut-out and crankcase heater. Famous brand compressor: Copeland, CHINAMFG and Danfoss. More reliable.

– Multi-protection design
• Electric panel consists of breakers and contactors for compressors, condenser & evaporator fan motors, phase sequence relay and other necessary protection devices for the main components.
• Main power supply breaker is optional.
• All electric parts are Schneider Electric brand.

3. Quieter operation

• Compressors and low noise Supply fan are mounted on rubber vibration dampers.
• Wave type acoustic Insulation for compressor section, thermal insulation for coil and fan section.

4. Easy installation & maintenance

• All units are factory assembled, internally wired, fully charged refrigerant.
• The Rooftops has provisions for forklift and crane lifting. On arrival to the job site they are ready to be lifted to their operating position through the lifting supports available on the units. Only connect the wires of power supply, and no need to connect any signal wires.
• Quick release fasteners or removable the access doors on the compressor, fan motor, filter, and electric box sections, provide convenient access to system components for maintenance and service.
• The unit provides external pressure gauge for convenient and fast checking system pressure without removing the panel.
• If the unit is in running with abnormal operation, the controller will show the error code for easy troubleshooting.
• Standard washable filter, easy to clean.

5. Control system

• The unit is completely factory-wired with necessary controls and terminal block for power wiring.
• Syslab wired controller is supplied with unit controls as standard. The precision control makes all heating, cooling, or ventilating decisions in response to electronic signals from sensors measuring indoor and outdoor temperatures.
• Besides standard Syslab wired controller, CHINAMFG & CHINAMFG PLC controller with BMS function and precision temperature & humidity control can be matched as optional solution.

Specifications (BD Series)

Cooling Capacity Ton 3.4 4.3 5.0 6.9 8.7 10.2
kW 12.0 15.2 17.5 24.0 30.3 35.6
Power Input kW 4.1 5.3 5.5 8.8 11.3 12.3
Running Current A 7.4 9.7 10.2 16.1 21.2 23.3
Heating Capacity kW 13.2 16.6 18.4 26.5 33.3 37.7
Power Input kW 3.8 4.8 5.1 8.2 10.4 11.3
Running Current A 6.9 9.2 9.7 15.1 20.1 22.2
Power Supply 380~415V/3Ph/50Hz
Refrigerant & Charging Quantity Type R410a
Kg 3.1 3.1 4.3 2×3.1 2×3.1 2×4.3
Compressor Type / Scroll
Brand / Copeland Copeland Copeland Copeland Copeland Copeland
Compressor/Circuit Nos. 1 1 1 2 2 2
Energy Adjustment % 0,100% 0,50%,100%
Condenser Type Copper Pipe + Anticorrosion Aluminium Fin
Condenser Fan Type Axial / Direct
Qty 1 1 1 1 1 1
Power Input kW 0.25 0.37 0.37 0.55 0.75 0.75
Airflow m3/h 4600 7800 7800 9000 12600 12600
Evaporator Type Copper Pipe + Anticorrosion Aluminium Fin
Evaporator Fan Type Direct Direct Direct Belt-Driven
Power Input kW 0.32 0.37 0.45 1.1 1.5 2.2
Supply Airflow m3/h 2100 2600 3400 4100 5200 6300
CFM 1235 1529 2000 2412 3059 3706
ESP Pa 100 100 100 200 200 250
Filter Standard Type G4 Panel Type Filter
Sound Level dB(A) 67 67 68 71 72 72
Dimension Length mm 1498 1498 1498 1978 1978 1978
Width mm 1100 1100 1100 1175 1175 1175
Height mm 1095 1095 1095 1095 1095 1095
Net Weight Kg 245 260 290 420 485 500

*** *** *** *** *** *** *** *** ***

Cooling Capacity Ton 12.7 14.3 17.1 20.0 25.7 30.0
kW 44.5 50.0 60.0 70.0 90.0 105.0
Power Input kW 17.0 19.5 22.8 26.7 32.9 39.7
Running Current A 31.7 35.6 39.9 48.3 61.0 70.6
Heating Capacity kW 48.7 54.3 64.0 75.4 96.2 113.2
Power Input kW 15.6 18.0 21.0 24.8 30.4 36.7
Running Current A 29.9 33.5 37.5 45.4 57.3 66.3
Power Supply 380~415V/3Ph/50Hz
Refrigerant & Charging Quantity Type R410a
Kg 4.3+8.5 4.3+8.5 2×7.5 2×8.5 3×7.5 3×8.5
Compressor Type / Scroll
Brand / Copeland Copeland Copeland Copeland Copeland Copeland
Compressor/Circuit Nos. 2/2 2/2 2/2 2/2 3/3 3/3
Energy Adjustment % 0,50%,100% 0,33%,66%,100%
Condenser Type Copper Pipe + Anticorrosion Aluminium Fin
Condenser Fan Type Axial / Direct
Qty 1 1 1 1 2 2
Power Input kW 1.1 1.5 1.5 2.2 2×1.1 2×1.5
Airflow m3/h 16500 21000 21000 27000 2×16500 2×21000
Evaporator Type Copper Pipe + Anticorrosion Aluminium Fin
Evaporator Fan Type Belt-Driven
Power Input kW 3 3 4 4 5.5 5.5
Supply Airflow m3/h 7600 8500 10900 12500 16000 19500
CFM 4471 5000 6412 7353 9412 11471
ESP Pa 250 250 300 300 300 300
Filter Standard Type G4 Panel Type Filter
Sound Level dB(A) 73 73 73 74 74 75
Dimension Length mm 2268 2268 2298 2298 2878 2878
Width mm 1470 1470 1650 1650 2140 2140
Height mm 1167 1167 1400 1400 1964 1964
Net Weight Kg 750 770 830 860 1150 1350


Project Reference

Sendo contribution to combat rising energy costs and global warming is to design innovative, efficient and dependable AC products, while providing best comfort and air quality. We are optimistic about the response that we expect to get from our potential customers because we strive to ensure that our customers get the quality products when they approach us and we are determined to ensure that our customers can obtain various benefits when they buy CHINAMFG Air Conditioners.

Get in touch with us and book a Factory Tour! Sincerely welcome to visit our factory at your convenience.

Type: Rooftop Packaged Air Conditioner
Air Tube Material: Galvanized Sheet
Corrosion Durability: Higher
Operating Voltage: 50Hz or 60Hz
Noise Level: Low
Application Fields: Residential & Commercial Field


air compressor

How Does Variable Speed Control Work in Screw Compressors?

Variable speed control in screw compressors is a technology that allows the compressor’s rotational speed to be adjusted according to the compressed air or gas demand. This control method offers several benefits in terms of energy efficiency and system performance. Here’s a detailed explanation:

Variable speed control, also known as variable frequency drive (VFD) or inverter control, works by adjusting the speed of the compressor’s drive motor. The drive motor is typically an electric motor that powers the rotation of the compressor’s screw rotors.

The key components and operation of variable speed control in screw compressors are as follows:

  • 1. Drive Motor: The drive motor is connected to the compressor’s screw rotors and provides the rotational power required for compression. It is an electric motor capable of operating at variable speeds.
  • 2. Inverter or Variable Frequency Drive (VFD): The inverter or VFD is an electronic device that controls the speed of the drive motor. It converts the incoming electrical power into adjustable frequency and voltage, allowing precise control of the motor’s rotational speed.
  • 3. Control System: The control system of the screw compressor monitors and adjusts the speed of the drive motor based on the compressed air or gas demand. It receives input signals from sensors that measure parameters such as pressure, flow rate, or system demand, and sends corresponding signals to the inverter or VFD to regulate the motor speed.
  • 4. Speed Adjustment: When the demand for compressed air or gas decreases, the control system reduces the motor speed by decreasing the frequency and voltage supplied by the inverter or VFD. This results in a lower rotational speed of the screw rotors, reducing the compression capacity and power consumption of the compressor.
  • 5. Energy Efficiency: Variable speed control allows the compressor to match the output to the actual demand, avoiding energy wastage associated with constant-speed compressors. By operating at lower speeds during periods of lower demand, energy consumption can be significantly reduced. This energy-saving capability is particularly advantageous in applications with varying air or gas requirements.
  • 6. Smooth Operation: Variable speed control enables smooth and gradual motor acceleration and deceleration, minimizing mechanical stress on the compressor components and reducing the likelihood of sudden pressure surges or system shutdowns.
  • 7. System Stability: By adjusting the compressor’s speed to match the demand, variable speed control helps maintain stable system pressure and prevents excessive cycling of the compressor. This contributes to improved system performance and longevity.

It’s worth noting that variable speed control is more commonly found in larger screw compressors used in industrial and commercial applications. Smaller screw compressors may utilize fixed-speed motors due to cost considerations or simpler system requirements.

Overall, variable speed control in screw compressors offers precise capacity modulation, improved energy efficiency, enhanced system stability, and reduced maintenance requirements, making it a preferred choice in many applications where compressed air or gas demand fluctuates.

air compressor

Can Screw Compressors Be Used for Medical Air Supply?

Yes, screw compressors can be used for medical air supply. Here’s a detailed explanation:

Screw compressors are commonly employed in various applications, including medical air supply systems. Medical air is a critical utility in healthcare facilities, used for various purposes such as respiratory therapy, anesthesia, and surgical tools. Here are some key points to consider:

1. Reliability and Efficiency:

Screw compressors are known for their reliability and efficiency. They can provide a continuous and reliable source of compressed air, ensuring a stable supply for medical applications. The rotary screw design allows for smooth and efficient compression, minimizing energy consumption and maximizing system performance.

2. Oil-Free Operation:

In medical applications, it is crucial to ensure the purity of the compressed air. Screw compressors can be designed and certified to provide oil-free air, eliminating the risk of oil contamination in the medical air supply. Oil-free screw compressors incorporate specialized sealing systems and filtration to prevent oil carryover, making them suitable for medical air applications.

3. Air Quality Standards:

Medical air must meet specific air quality standards to ensure patient safety and treatment effectiveness. Standards such as the European Pharmacopoeia (Ph. Eur.) or the United States Pharmacopeia (USP) define the required purity levels for medical air, including limits on particulate matter, moisture content, and microbial contamination. Screw compressors can be equipped with appropriate filtration and purification systems to meet these standards.

4. Integrated Drying and Filtration:

Some screw compressors designed for medical air applications incorporate integrated drying and filtration systems. These systems remove moisture and contaminants from the compressed air, ensuring it meets the required quality standards. Integrated drying systems can include refrigerated dryers, desiccant dryers, or membrane dryers, depending on the specific needs of the medical air supply system.

5. Redundancy and Backup Systems:

Medical air supply systems often require a high level of reliability and continuity. Screw compressors can be configured with redundancy and backup systems to ensure uninterrupted supply. Multiple compressors can be installed in parallel, with automatic switching mechanisms to maintain supply in case of a compressor failure or maintenance activities.

6. Monitoring and Alarms:

Modern screw compressors used in medical air supply systems often feature advanced monitoring capabilities. They can continuously monitor and record key parameters such as pressure, temperature, and system performance. Alarms and alerts can be configured to notify operators or maintenance personnel in case of abnormal conditions or potential issues with the compressor.

7. Compliance with Standards and Regulations:

When using screw compressors for medical air supply, it is essential to comply with relevant standards and regulations. These may include medical device regulations, electrical safety standards, and guidelines specific to medical gas systems. Compliance ensures that the medical air supply system meets the necessary safety and quality requirements.

In summary, screw compressors can be used for medical air supply, providing reliable and efficient compressed air for various medical applications. With their reliability, oil-free operation, adherence to air quality standards, integrated drying and filtration capabilities, and the ability to incorporate redundancy and monitoring features, screw compressors are well-suited for medical air supply systems in healthcare facilities.

air compressor

What Is a Screw Compressor?

A screw compressor is a type of positive displacement compressor that operates based on the principle of rotary motion. Here’s a detailed explanation:

Working Principle:

A screw compressor consists of two helical rotors, typically called male and female rotors, that rotate in opposite directions within a housing. The rotors have specially designed profiles that interlock with each other, creating a series of compression chambers as they rotate. As the rotors rotate, the volume of these chambers decreases, compressing the air or gas trapped inside.

Compression Process:

As the air or gas enters the screw compressor, it gets trapped between the rotors’ lobes or threads. As the rotors continue to rotate, the trapped air or gas is carried along the length of the rotors and gradually compressed. The compression occurs continuously and smoothly as the air or gas moves from the suction side to the discharge side of the compressor. The interlocking rotors ensure a continuous flow of compressed air or gas without pulsation.

Oil-Injected and Oil-Free Variants:

Screw compressors are available in both oil-injected and oil-free variants. In oil-injected screw compressors, a small amount of lubricating oil is injected into the compression chamber to provide lubrication, cooling, and sealing between the rotors. The oil also helps in reducing friction and minimizing wear. Oil-injected screw compressors are commonly used in various industrial applications where a small amount of oil in the compressed air is acceptable.

On the other hand, oil-free screw compressors are designed to operate without the need for oil lubrication. These compressors use specialized rotor coatings, such as PTFE (polytetrafluoroethylene) or other non-stick materials, to reduce friction and prevent the need for oil. Oil-free screw compressors are often favored in applications where oil-free and contaminant-free compressed air is essential, such as in food and beverage, pharmaceutical, and electronics industries.


Screw compressors are widely used in various industries for a range of applications. They are commonly employed in manufacturing plants, refineries, power generation facilities, and other industrial settings to supply compressed air or gas for pneumatic tools, process equipment, air conditioning systems, and more. The ability of screw compressors to deliver a continuous flow of compressed air or gas makes them suitable for applications that require a steady and reliable source of compressed air.


Screw compressors offer several advantages compared to other types of compressors. They provide high efficiency and can deliver a large volume of compressed air or gas. The continuous compression process results in smooth operation with minimal pulsation. Additionally, screw compressors are known for their compact design, low vibration levels, and relatively quiet operation.

In summary, a screw compressor is a rotary positive displacement compressor that uses interlocking helical rotors to compress air or gas. It operates based on a continuous compression process and is available in both oil-injected and oil-free variants. Screw compressors find widespread use in various industries for applications that require a reliable source of compressed air or gas.

China Good quality CHINAMFG Air Cooled Rooftop Packaged Units Scroll/Piston/Screw Compressor   air compressor partsChina Good quality CHINAMFG Air Cooled Rooftop Packaged Units Scroll/Piston/Screw Compressor   air compressor parts
editor by CX 2023-10-10

Leave a Reply

Your email address will not be published. Required fields are marked *