MANUAL INSTALLATION AND OPERATION Rotary Compressors RK, RG and HG 1 General Information 1.1 1.2 1.3 1.4 The working principle of the Rotary Compressor Range Performance Voltage and range of operation 1.4.1 1.4.2 1.5 1.6 1.7 Single phase Three phase 5 5 6 7 7 7 7 8 8 8 Dimensions and connections Mountings Oil type 2 Operating Range 2.1 2.2 2.3 Operating envelope Operating compression ratio Operating pressure differential 9 9 9 9 3 Temperature Criteria 3.1 3.2 3.3 3.4 Ambient temperature Discharge temperature Motor temperature Return gas temperature 10 10 10 10 10 4 General Recommendations 4.1 4.2 System requirements Pipework design 4.2.1 4.2.2 4.2.3 4.2.4 4.2.5 4.3 4.3.1 4.3.2 2 11 11 11 11 14 14 14 16 21 21 21 21 21 21 Pipework design advice/guidance Connections Flexible connections Velocity within pipework and heat exchangers Capillaries Advice for installers Refrigerant charge Frequency of starts Start-up pressure Refrigerant charge 4.4 Starting 4.4.1 4.4.2 4 General Recommendations (continued) 4.5 4.6 Liquid return whilst operating Liquid migration during prolonged shutdown 4.6.1 4.6.2 4.7 Band heaters Non-return valves 22 22 22 22 22 Purging refrigerant from the system 5 Security 5.1 5.2 5.3 Pressure Electrical Declaration of incorporation 23 23 23 23 6 Appendices 6.1 6.2 Documents Contacts 25 25 25 3 Tecumseh Europe with its long experience of compressor development has introduced a range of rotary compressors for air conditioning and commercial refrigeration. This operating manual has been designed to help you correctly install this compressor range in your applications. 1 1.1 General Information The working principle of the Rotary Compressor 1 | Names of the different pieces 2 | End of suction and the start of compression 3 | Start of compression and suction 4 | Compression and suction 5 | Compressed gas exit Rotary compressors are `high pressure shell' type compressors. The suction on these compressors is taken directly into the compression chamber. Gas compressed in the compression chamber is discharged into the compressor casing. It should be noted that from a cold start-up, high pressure shell type compressors take longer to reach their normal operating pressure in the compressor shell. This is partly due to the larger volume of the compressor casing and partly as a result of refrigerant being trapped in the oil. Any refrigerant in the oil has to completely evaporate before condensing pressure can reach its operating level. 5 Sucking bottle Excessive refrigerant, oil or impurity in the suction chamber of the compressor can result in mechanical damage. As a result, all our compressors are fitted with an accumulator equipped with a filter. AIR CONDITIONING COMMERCIAL VERTICAL RG range, accumulator capacity > 100 cm3 RK range, accumulator capacity > 160 cm3 RG range, accumulator capacity > 680 cm3 HORIZONTAL HG range, accumulator capacity > 70 cm3 HG range, accumulator capacity > 405 cm3 Please note that overcharging with refrigerant is one of the major causes of damage to the compressor. It is important to check the amount of refrigerant being used is correct. 1.2 Range VERTICAL Application RG R22 Air Conditioning or Heat Pump HORIZONTAL RK R22 R134a HG R22 R407C Commercial Refrigeration Low Back Pressure Commercial Refrigeration High Back Pressure R407C R407C R404A R134a R404A R404A R134a R404A 6 1.3 1.4 Performance Please refer to the Technical Data Sheets for information on compressor performance. Voltage and range of operation The voltage range of the rotary compressors corresponds to the standard ranges defined by Tecumseh Europe. See the General Catalogue for more information. Start-up should never be carried out when the electrical cover has been removed. 1.4.1 Single phase Single phase compressor motors are two pole asynchronous and they are designed to be used with different types of starting method depending on the application (PSC, CSR, CSIR). Please ensure the starting mode follows that specified on the Technical Data Sheet for each product. We recommend the use of components specified by Tecumseh Europe. For wiring instructions, follow the diagram supplied with the compressor. Ensure that the start and run windings are connected correctly otherwise damage to the motor will result (see label below). 1.4.1.1 Motor protection The motor is protected by an externally mounted temperature and current sensitive overload. It is imperative that the overload protector is connected as it cuts off the power supply to the compressor if a fault occurs. For wiring instructions, follow the wiring diagram supplied with the compressor. 1.4.2 Three phase All rotary compressors which have a model number beginning with a letter `T' are equipped with a three phase motor. Three phase motors are wired in star, and the resistance measured between two terminals corresponds to the resistance of that coil. Ensure that each compressor conforms to the information given on the Technical Data Sheet. We recommend the use of components specified by Tecumseh Europe. For wiring instructions, follow the diagram supplied with the compressor. 1.4.2.1 Phase control Care should be taken when connecting three phase rotary compressors to ensure that the direction of rotation is correct as rotation occurs in one direction only. ATTENTION: If the rotational direction is incorrect, the compressor will not refrigerate and the life of the product will be reduced. However, a short test period will not cause damage. To ensure correct rotation we recommend the use of our phase detector reference number 8 535 136, which is listed in our Spare Parts and Accessories Catalogue. 1.4.2.2 Protection of the motor The motor is protected from overheating by an external overload protector which must be connected. This device has a single contact and cannot be wired into the three phase electrical supply of the compressor (a three phase motor can only operate with a minimum of 2 active phases). The protector should therefore be wired into the control circuit of the compressor so that it cuts the power supply if a fault occurs. For wiring instructions, see the electrical diagram supplied with the compressor. For further information on protecting the compressor against high current, please contact the technical application department at Tecumseh Europe. 7 1.5 Dimensions and connections The dimensions and the position of the connections are given in our Technical Data Sheets. The compressors can tolerate an angle of tilt of +/- 7° for vertical models and +5°/0° for horizontal versions. 1.6 Mountings We recommend the fitting of anti-vibration mounting feet as specified by Tecumseh Europe (see table below). Natural or synthetic rubber products bearing weight for long periods tend to loose their shape. This occurs more quickly when they are subject to an excessive loading and/or heat. Anti-vibration mounting feet should be regularly checked to ensure optimal operation of the installation and replaced where necessary to ensure the sound level does not increase. MAXIMUM STANDARD RANGE MOUNTING RG HG RK 3 feet 4 feet 3 feet PLAY SETTINGS 8 682 021 8 682 025 8 682 021 13.8 Nm to 17.9 Nm (10 to 13 ft.lbs) STANDARD TORQUE The length of the AV mount insert used allows the mounts to function correctly and prevents overtightening. Specific mounts can be supplied for applications where greater vibration reduction is required. For further information, contact your local representative. 1.7 Oil type APPLICATION REFRIGERANT R22 Air Conditioning or Heat Pump OIL Alkyl Benzene Short pipe run* (<3,6m): Alkyl Benzene Long pipe run* (3,6m): PVE R407C R134a Polyolester Polyvinyl ether Polyvinyl ether Polyolester Commercial Refrigeration Low Back Pressure Commercial Refrigeration High Back Pressure R404A R404A R134a * Short or long pipe run: Distance between the condenser and the evaporator. The design of the rotary compressors is such that an oil change or the addition of oil should not be carried out. We strongly advise against adding oil to the refrigeration system whether the pipework is long or short. 8 2 2.1 Operating Range Operating envelope The operating envelope is in accordance with EN 12 900, with a superheat of 10K for air conditioning and heat pump applications, and return gas of 20°C for all other applications (See diagrams in the appendices). For more information please refer to the Technical Data Sheet for each product. 2.2 Operating compression ratio The operating compression ratio is the ratio between absolute condensing and evaporating pressures. It is essential to adhere to the maximum values listed in the following table. Exceeding these values will reduce the working life of the compressor or even cause a breakdown. APPLICATION REFRIGERANT R22 Air Conditioning or Heat Pump COMPRESSION RATIO 7 15.8 7 22 8 15.8 R134a R407C Commercial Refrigeration Low Back Pressure Commercial Refrigeration High Back Pressure R404A R404A R134a 2.3 Operating pressure differential The operating pressure differential corresponds to the difference between absolute discharge and suction pressure. Maximum levels are listed in the table below. Exceeding these values will reduce the working life of the compressor or even cause a breakdown. APPLICATION REFRIGERANT R22 Air Conditioning or Heat Pump PRESSURE DIFFERENTIAL (BAR) 22 23.5 23 27.1 25 23 R407C R134a Commercial Refrigeration Low Back Pressure Commercial Refrigeration High Back Pressure R404A R404A R134a 9 3 3.1 Temperature Criteria Ambient temperature The compressors have been designed to operate in the following ambient temperatures (with forced air cooling). AMBIENT TEMPERATURE Air Conditioning or Heat Pump Commercial Refrigeration 46°C 43°C Comment: For air conditioning applications operating in high ambient conditions, see our tropical range. These products use R-134a and have an evaporating temperature range of ­10°C to +30°C, and a condensing temperature range of +30°C to +80°C for a temperature of 55°C. 3.2 Discharge temperature The maximum discharge temperature is 127°C. This temperature can be measured by soldering a thermocouple onto the discharge pipe 5 cm from the compressor and insulating it for 10 cm. 3.3 Motor temperature All our single phase rotary compressors are supplied with an external overload protector. The maximum permitted operating temperature is 130°C which is measured by the resistance variation method. Resistance variation method: Leave the application switched off in a constant temperature (temperature t1) for at least 8 hours. Measure the motor winding resistance R1 at this temperature t1. With three phase motors, measure the resistance between 2 electrical supply terminals to the compressor. Run the application in the most difficult conditions foreseeable, switch off the machine and immediately measure the new motor winding resistance (R2). With three phase motors, measure the resistance between the 2 terminals used before. The new temperature t2 can easily be calculated using the following equation: t1 & t2 are given in degrees Celsius. 3.4 Return gas temperature A minimum superheat of 10K is necessary between the evaporating temperature and suction temperature at the inlet of the compressor. However, it is necessary to control superheat to prevent exceeding the maximum return gas temperature for the compressor and the compressor motor (see sections 3.2 and 3.3). 10 4 4.1 General Recommendations System requirements Rotary compressors are `direct suction'. The suction gas enters directly into the compression chamber. The suction accumulator incorporates a filter to protect the compressor against dirt and debris entering the pump. It is essential that all necessary precautions are taken to ensure the system is kept clean during installation and service e.g. purge the system with Nitrogen whilst brazing. 4.2 Pipework design The function of the pipework is to allow the refrigerant to circulate through the system components in such a way as to provide optimum operating conditions, i.e.: > Limited pressure drop, > Velocity is sufficient to entrain the oil, > Ensure that the compressor is protected against the return of liquid refrigerant particularly when the installation is switched off. > A full head of liquid refrigerant at the expansion device. As in all refrigerating systems using hermetic compressors, some of the oil from the compressor circulating within the system is entrained with the refrigerant. The amount varies according to the operating conditions of the installation. No additional components e.g. oil separator, oil coolers etc. are required to assist with oil control in rotary compressor systems. However, it is essential to ensure the oil return to the compressor otherwise its working life may be shortened and its performance affected. All pipework in the refrigerating system must be designed to return oil to ...