Danfoss Inverter scroll compressor, VRJ

Transcription

1 Application Guidelines Danfoss Inverter scroll compressor, VRJ For Residential Applications - R410A

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4 Contents Introduction...6 Scroll compressor components... 6 Compressor size... 6 Performance... 6 Compressor model designation...7 Nomenclature... 7 Label... 7 Serial number... 7 Technical specifications...8 Compressor specifications... 8 Performance data... 8 Variable speed drive specifications... 8 Bearings lubrication... 8 Dimensions...9 VRJ Electrical data, connections and wiring...10 Supply Voltage...10 Compressor electrical specifications...10 LRA (Locked Rotor Amp)...10 MCC (Maximum Continuous Current)...10 Winding resistance...10 Wiring connections...11 Terminal cover mounting...11 Terminal cover removal...11 IP rating...11 Internal motor protection...11 Phase sequence and reverse rotation protection...11 Approvals and certificates...12 Approval and certificates...12 Pressure equipment directive 97/23/EC...12 Low voltage directive 73/23/EC, 93/68/EC...12 Internal free volume...12 Operating conditions...13 Refrigerant and lubricants...13 Motor supply...13 Compressor ambient temperature FRCC.PC.019.A2.22

5 Contents Application envelope...14 High and low pressure protection...15 Crankcase heating...15 Oil return management...15 On/off cycling (cycle rate limit)...16 Start-up sequence...16 System design recommendations...17 General...17 Essential piping design considerations...17 Refrigerant charge limit...18 Reversible heat pump systems...18 Minimum sump superheat...18 Preventing liquid flood back...18 Water utilising systems...19 Loss of charge protection...19 Oil level checking and top-up...19 Sound and vibration management...20 Starting sound level...20 Running sound level...20 Stopping sound level...20 Sound generation in a refrigeration system and air conditioning system...20 Installation...22 System cleanliness...22 Compressor handling and storage...22 Compressor mounting...22 Compressor holding charge...22 Tube brazing procedure...22 Brazing material...22 Compressor connection...23 Vacuum evacuation and moisture removal...23 Liquid line filter driers...24 Refrigerant charging...24 Insulation resistance and dielectric strength...24 Compressor replacement after motor burn out...24 Ordering information and packaging...25 Packaging...25 Ordering code numbers...25 FRCC.PC.019.A2.22 5

6 Introduction Danfoss VRJ for residential applications developed by Danfoss is a complete package consisting of a dedicated variable speed compressor, variable speed drive, application controller, electronic expansion valve (EEV), EEV controller and sensors. Three nominal system sizes are available (3, 4 and 5 TR), based on three compressor models. These Selection & Application Guidelines focus on the variable speed scroll compressor. Scroll compressor components The motor stator is rigidly attached to the shell. The rotor is shrink-fit onto the eccentric shaft. The shaft is supported by two bearings, one in the crankcase and the second below the motor. Compressor size Performance Variable speed technology offers more flexibility in compressor selection than fixed speed compressors. Selection of the right variable speed compressor size can be done by different methods: Maximum cooling capacity: select a compressor size that achieves the peak load system cooling capacity demand at its maximum speed. Nominal cooling capacity: select a compressor size that achieves the nominal system cooling capacity at a rotational speed of rpm (50-70Hz). Best Seasonal Efficiency Ratio: select a compressor size that achieves the minimum The Danfoss VRJ compressors referenced in this guide is a fully compliant scroll and actually improves with run time in its early commissioning. system cooling demand at its minimum speed. Ensure that the compressor is able to cover the peak load system cooling capacity. This selection makes the compressor to run for a maximum of time at part load where the system efficiency is highest. Danfoss scroll compressors are manufactured using the most advanced machining, assembly, and process control techniques. In design of both the compressor and the factory, very high standards of reliability and process control were first priority. The result is a highly efficient product with the highest reliability obtainable, and a low sound level. A seventy-two hour run-in is recommended to meet performance expectations. 6 FRCC.PC.019.A2.22

7 Compressor model designation Nomenclature Application, Family & Refrigerant Swept Volume Model Variation Voltage Motor Protection Equipment Version Other Features VRJ 028 U K N P 6 Application, Family & refrigerant V: Variable speed R: Residential J: R410A, PVE lubricant Swept Volume Displacement in cc/rev Other features 6: No other features Equipment version P: Brased connections, spade terminals Motor protection N: No internal motor protection (protection by drive) Model Variation U: Design optimised for high SEER Voltage K: 420V DCL IPM Label Serial number S K Manufacturing location Incremental number Production week Production year FRCC.PC.019.A2.22 7

8 Technical specifications Compressor specifications Compressor Swept volume Displacement Oil charge Net weight model Min speed 30 Hz 60 Hz Max speed cu.in/rev 900 rpm 1800 rpm 3600 rpm 4200 rpm oz lb VRJ VRJ VRJ Performance data Conditions High SEER conditions (H) CHEER conditions Heat Pump conditions SEER conditions (I) Compressor model VRJ028 VRJ035 VRJ044 VRJ028 VRJ035 VRJ044 VRJ028 VRJ035 VRJ044 Nominal Tons 3 Tons 4 Tons 5 Tons 3 Tons 4 Tons 5 Tons 3 Tons 4 Tons 5 Tons Compressor speed Compressor capacity Compressor rpm Hz Btu/hr Ton isentropic efficiency VRJ028 3 Tons VRJ035 4 Tons VRJ044 5 Tons Conditions High SEER conditions (H) CHEER conditions Heat Pump conditions SEER conditions (I) Evaporating Temperature ( F) Condensing Temperature ( F) Superheat ( F) Subcooling ( F) Variable speed drive specifications For dedicated variable speed drive specifications, refer to Danfoss VRJ Installation and Operation instructions. Bearings lubrication A specific oil pump ensures optimal bearing lubrication at all compressor speeds. This to have sufficient bearing lubrication at low speeds as well as avoid excessive Oil Circulation Ratio (OCR) at high speeds. 8 FRCC.PC.019.A2.22

9 Dimensions VRJ x Ø Discharge port 1/2 ODF Suction port 3/4 ODF All dimensions in inch Mounting grommet /16-18 UNC self tapping Ø Ø Recommended torque for mounting bolts: 8 ft.lbs (±1ft.lbs) FRCC.PC.019.A2.22 9

10 Electrical data, connections and wiring Supply Voltage VRJ compressors must not be connected directly to the mains supply. They must only be powered through the dedicated Danfoss variable speed drive. Compressor model VRJ028 VRJ035 VRJ044 Variable Speed Drive Model 176L L L7002 Nominal voltage Voltage range V 1Ph 60Hz V Refer to Danfoss VRJ Installation and Operation instructions for more details about supply voltage. Compressor electrical specifications Compressor model LRA MCC Winding resistance A A Ohm VRJ VRJ VRJ LRA (Locked Rotor Amp) MCC (Maximum Continuous Current) LRA is the higher average current as measured on a mechanically blocked compressor tested under nominal voltage. LRA is printed on the nameplate, according to UL requirements. With The MCC value is the maximum at which the compressor can be operated in transient conditions and out of the operating envelope. The VRJ compressors, the LRA value is low because the variable speed drive reacts very rapidly (far below 1 second). MCC value is measured based on UL conditions (max load) and at low voltage. Winding resistance VRJ scroll compressors are equipped with an IPM (permanent magnet) motor. Winding resistance is the resistance between indicated terminal pins at 77 F (resistance value ± 7%). Winding resistance is generally low and it requires adapted tools for precise measurement. Use a digital ohm-meter, a 4 wires method and measure under stabilised ambient temperature. Winding resistance varies strongly with winding temperature ; If the compressor is stabilised at a different value than 77 F, the measured resistance must be corrected with following formula: a + t amb R tamb = R 77 F a + t 77 F t 77 F : reference temperature = 77 F t amb : temperature during measurement ( F) R 77 F : winding resistance at 77 F R tamb : winding resistance at t amb a: Coefficient a= FRCC.PC.019.A2.22

11 Electrical data, connections and wiring Wiring connections VRJ scroll compressors will only compress gas while rotating counter-clockwise (when viewed from the compressor top). The drawing shows electrical terminal labelling and should be used as a reference when wiring the compressor. Terminal cover mounting Terminal cover removal T1, T2 and T3 of the drive and the compressor must be connected accordingly. Refer to Danfoss VRJ Installation and Operation instructions for details and cable sizes. The terminal cover and gasket should be installed prior to operation of the compressor. The terminal cover has two outside tabs, 180 degrees apart, that push Quick connect spade terminals P terminal box type engage the terminal fence. When installing the cover, check that it is not pinching the lead wires. push push IP rating The compressor terminal box IP rating according to CEI 529 is IP22 for all models. This IP rating is only valid when correctly sized cable glands with the same IP rating are applied. First numeral, level of protection against contact and foreign objects 2 protection against object size over 1/2 inch (fingers of similar) Second numeral, level of protection against water 2 protection against dripping water when tilted up to 15 Internal motor protection Phase sequence and reverse rotation protection VRJ scroll compressors are not equipped with an internal motor protector. Motor protection is provided by the variable speed drive. All The compressor will only operate properly in a single direction. If electrical connections are done correctly between the drive and the compressor terminals (compressor and drive terminals T1, T2 and T3 matching), the drive will provide correct phase supply to the compressor, and reverse rotation will be not possible. motor para-meters are factory preset in order to guaranty optimal locked rotor or overload current protection. If compressor and drive T1, T2 and T3 terminals are not matching, the compressor can go in reverse rotation. This results in excessive noise, no pressure differential between suction and discharge, and suction line warming rather than immediate cooling. The compressor can be rapidly severely damaged in these conditions. FRCC.PC.019.A

12 Approvals and certificates Approval and certificates VRJ scroll compressors comply with the following approvals and certificates. UL (Underwriters Laboratories) Other approvals / certificates All models Contact Danfoss Pressure equipment directive 97/23/EC Refrigerating fluids Group 2 Category PED I Evaluation module no scope Low voltage directive 73/23/EC, 93/68/EC Manufacturer's declaration of incorporation ref. EC Machines Directives 98/392/CE Contact Danfoss Internal free volume Products Internal free volume at LP side without oil (in. 3 ) VRJ FRCC.PC.019.A2.22

13 Operating conditions Refrigerant and lubricants General information PVE Residual moisture Motor supply Compressor ambient temperature High ambient temperature Low ambient temperature VRJ scroll compressor application range is influenced by several parameters which need to be monitored for a safe and reliable operation. These parameters and the main recommendations for good practice and safety devices are explained hereunder: When choosing a refrigerant, different aspects must be taken into consideration: Legislation (now and in the future) Safety Application envelope in relation to expected running conditions Compressor capacity and efficiency Compressor manufacturer recommendations & guidelines Polyvinyl ether (PVE) is an innovative refrigeration lubricant for HFC refrigerant systems. PVE is as hygroscopic as existing polyolester lubricants (POE), but PVE does not chemically react with water; no acids are formed and compressor evacuation is easier. Prior to shipment from the factory, every compressor is dehydrated, evacuated, and charged with dry nitrogen. Maximum residual VRJ scroll compressors can be operated only connected to the dedicated variable speed drive, at nominal voltages as indicated in supply VRJ scroll compressors can be applied from -13 F to 125 F ambient temperature. The compressors are designed as 100 % suction gas In case of enclosed fitting and high ambient temperature, it is recommend to check the Although the compressor itself can withstand low ambient temperature, the system may require specific design features to ensure safe Refrigerant and lubricants Motor supply Compressor ambient temperature Application envelope (evaporating temperature, condensing temperature, return gas temperature) Additional points could influence the final choice: Environmental considerations Standardisation of refrigerants and lubricants Refrigerant cost Refrigerant availability The compressor technology applied in Danfoss VRJ scroll compressors in combination with PVE lubricant provides the best possible result in terms of reliability and compressor lifetime. moisture levels are oz. for model VRJ028, and oz. for VRJ035 and VRJ044. voltage section. Under-voltage and over-voltage operation is allowed within the indicated voltage range. cooled without need for additional fan cooling. Ambient temperature has very little effect on the compressor performance temperature of power wires and conformity to their insulation specification. and reliable operation. See below sections for recommendations. FRCC.PC.019.A

14 Operating conditions Application envelope The operating envelope for VRJ scroll compressors is given in the figure below, where the condensing and evaporating temperatures represent the range for steady-state operation. Under transient conditions, such as start-up and defrost for heat pump applications, the compressor may operate outside this envelope for short periods. The operating limits serve to define the envelope within which reliable operations of the compressor are guaranteed: Maximum discharge gas temperature: +275 F Suction superheat is dedictated by the minimum sump superheat (see graph p16). Maximum superheat of 40 F Minimum and maximum evaporating and condensing temperatures, as per the operating envelopes. All the below limits, temperatures and speeds, are secured by the parameters in the drive and application controller software s. Saturated condensing temp. ( F) RPM RPM RPM RPM RPM RPM RPM ( C) RPM Derated RPM Saturated evaporating temp. ( F) ( C) Maximum discharge gas temperature The discharge temperature depends mainly on the combination of evaporating temperature, condensing temperature and suction gas superheat and speed. Discharge gas temperature should be controlled with an insulated sensor attached to the discharge line, 6 in. from the compressor shell. Maximum discharge gas temperature must not exceed 275 F when the compressor is running within the approved operating envelope. Refer to Danfoss VRJ Installation and Operation instructions for connection details, and to Sensor Selection Guideline manual for selection details and technical brochures about temperature sensors. 14 FRCC.PC.019.A2.22

15 Operating conditions High and low pressure protection Suction and discharge pressure transmitters have to be installed and connected to the variable speed drive to ensure the compressor operates within the application envelope described above. Refer to Danfoss VRJ Installation and Operation instructions for connection details, and to Sensor Selection Guideline manual for selection details and technical brochures about pressure transmitters. Pressure settings R410A Working pressure range high side psig Working pressure range low side psig Maximum high pressure safety switch setting psig 653 Minimum low pressure safety switch setting psig 22 High pressure Low pressure High pressure ratio Crankcase heating Oil return management : LP safety switch shall never be bypassed According to UL requirements, a high pressure safety switch is still mandatory in any system, even with high pressure transmitters connected and used via the variable speed drive. HP switch settings shall not exceed the maximum service pressure of any system components. The high-pressure switch can be set to lower values A low pressure (LP) safety switch is recommended. Deep vacuum operations of a scroll compressor can cause internal electrical arcing and scroll instability. Danfoss scroll compressors exhibit high volumetric efficiency and may draw very low vacuum levels, which could induce such a problem. The minimum Scroll compressors are machines with fixed volume ratio, and operate more efficiently near the design pressure ratio. In the extreme, do not exceed a 7.5:1 pressure ratio (absolute discharge pressure to absolute suction pressure) A crankcase heating function can be provided by injecting a DC current in the motor of the compressor, to keep the compressor warm, and avoid liquid migration during off cycle. A specific function can be enabled to secure the oil return to the compressor. When the compressor is running at minimum speed for depending on the application and ambient conditions. The HP switch must either be placed in a lockout circuit or consist of a manual reset device to prevent cycling around the highpressure limit. If a discharge valve is used, the HP switch must be connected to the service valve gauge port, which must not be isolated. low-pressure safety switch (loss of charge safety switch) setting is given in the above table. Either the LP safety switch must be a manual lockout device or an automatic switch wired into an electrical lockout circuit. The LP switch tolerance must not allow for vacuum operations of the compressor. for extended periods. The Danfoss VRJ scroll compressor is equipped with an internal pressure relief valve for protection against blocked condenser and fan failure conditions. Refer to Danfoss VRJ Installation and Operation instructions for details. extended periods, every half hour, speed will be increased to 2400 rpm for a 80 seconds period. FRCC.PC.019.A

16 Operating conditions On/off cycling (cycle rate limit) The on/off cycling protection is included in the variable speed drive. There is no need for extra on/off cycling protection. Start-up sequence To ensure correct lubrication of all the mechanical parts, VRJ compressors start with a defined ramp-up, and stay at a fixed speed for some seconds. Then the compressor speed increases up to the desired set point according to capacity request. 16 FRCC.PC.019.A2.22

17 System design recommendations General Essential piping design considerations Successful application of scroll compressors is dependent on careful selection of the compressor for the application. If the compressor is not correct for the system, it will operate Proper piping practices should be employed to ensure adequate oil return, even under minimum load conditions with special consideration given to the size and slope of the tubing coming from the evaporator. Tubing returns from the evaporator should be designed so as not to trap oil and to prevent oil and refrigerant migration back to the compressor during off-cycles. It is particularly important and critical with variable capacity systems, where very low velocities can be achieved for long periods of time, generating oil return issues. If the evaporator lies above the compressor, as is often the case in split or remote condenser systems, the addition of a pump-down cycle is strongly recommended. If a pump-down cycle were to be omitted, the suction line must have a loop at the evaporator outlet to prevent refrigerant from draining into the compressor during off-cycles. If the evaporator were situated below the compressor, the suction riser must be trapped so as to prevent liquid refrigerant from collecting at the thermal bulb location (see fig. 1). beyond the limits given in this manual. Poor performance, reduced reliability, or both may result. When the condenser is mounted at a higher position than the compressor, a suitably sized «U»-shaped trap close to the compressor is necessary to prevent oil leaving the compressor from draining back to the discharge side of the compressor during off cycle. The upper loop also helps avoid condensed liquid refrigerant from draining back to the compressor when stopped (see fig. 2). The maximum elevation difference between the indoor and outdoor section cannot exceed 26 feet. System manufacturers should specify precautions for any applications that exceed these limits to ensure compressor reliability. Piping should be designed with adequate threedimensional flexibility. It should not be in contact with the surrounding structure, unless a proper tubing mount has been installed. This protection proves necessary to avoid excess vibration, which can ultimately result in connection or tube failure due to fatigue or wear from abrasion. Aside from tubing and connection damage, excess vibration may be transmitted to the surrounding structure and generate an unacceptable noise level within that structure as well (for more information on noise and vibration, see the section on: Sound and vibration management section. fig % slope, 13 ft/s or more U-trap To condenser fig. 2 Upper loop Condenser max. 13 ft max. 13 ft 26 to 40 ft/s U-trap, as short as possible 0.5 % slope, 13 ft/s or more Evaporator U-trap HP LP 3D flexibility U-trap, as short as possible FRCC.PC.019.A

18 System design recommendations Refrigerant charge limit Reversible heat pump systems Minimum sump superheat Scroll compressors can tolerate liquid refrigerant up to a certain extend without major problems. However, excessive liquid refrigerant in the compressor is always unfavourable for service life. Besides, the installation cooling capacity may be reduced because of the evaporation taking place in the compressor and/or the suction line Transients are likely to occur in reversible heat pump systems, i.e. a changeover cycle from cooling to heating, defrost or low-load short cycles. These transient modes of operation may lead to liquid refrigerant carryover (or flood back) or excessively wet refrigerant return conditions. As such, reversible cycle applications The minimum sump temperature is in the range from 10 F to 30 F above saturated suction instead of the evaporator. System design must be such that the amount of liquid refrigerant in the compressor is limited. In this respect, follow the guidelines given in the section: Essential piping design recommendations in priority. require specific precautions for ensuring a long compressor life and satisfactory operating characteristics. Specific tests for repetitive flood back are required to confirm whether or not special system design considerations should be considered. temperature. Refer to the flood back test criteria. 40 Floodback requirement Sump superheat, F Acceptable Unacceptable Saturated suction temp. F Preventing liquid flood back Danfoss recommends the use of an electronic expansion valve for all air conditioning and heat pump applications with VRJ compressors. An EXV has two key benefits: it provides modulating control of the system under varying load conditions, and it protects the compressors from flood back during adverse running conditions. Exceptions to the use of EXV s with Danfoss VRJ must be approved by Danfoss application engineering. 18 FRCC.PC.019.A2.22

19 System design recommendations Water utilising systems Loss of charge protection Oil level checking and top-up Apart from residual moisture in the system after commissioning, water could also enter the refrigeration circuit during operation. Water in the system shall always be avoided. Not only because it can shortly lead to electrical failure, sludge in sump and corrosion but in particular because it can cause serious safety risks. Common causes for water leaks are corrosion and freezing. Corrosion: Materials in the system shall be compliant with water and protected against corrosion. VRJ scroll compressors together with the variable speed drive include a loss of charge protection function. This protection is ensured if pressure In installations with good oil return and line runs up to 50 ft, no additional oil is required. If installation lines exceed 50 ft, additional oil may be needed. 1 or 2% of the total system refrigerant charge (in weight) can be used to roughly define the required oil top-up quantity. Freezing: When water freezes into ice its volume expands which can damage heat exchanger walls and cause leaks. During off periods water inside heat exchangers could start freezing when ambient temperature is lower than 32 F. During on periods ice banking could occur when the circuit is running continuously at too low load. Both situations should be avoided by connecting a pressure and thermostat switch in the safety line. and temperature sensors are connected to the drive. Always use oil from new cans. Top-up the oil while the compressor is idle. Use any accessible connector on the compressor suction line and a suitable pump. FRCC.PC.019.A

20 Sound and vibration management Starting sound level Running sound level During start-up transients, it is natural for the compressor sound level to be slightly higher than during normal running. Danfoss scroll VRJ scroll compressors are designed with optimised discharge ports and wrap geometry compressors exhibit very little increased start-up transient sound. to reduce the sound level when a compressor is running. Sound level vs Speed Sound power level (dba) / / / / / Condition (Tsat(suction) / Tsat (discharge) and speed (RPM) 45/ Stopping sound level Sound generation in a refrigeration system and air conditioning system Compressor sound radiation VRJ scroll compressors have very low shutdown sound due to minimal volume of discharge volume to push scrolls in reverse at shutdown. Typical sound and vibration in refrigeration and air conditioning systems encountered by design and service engineers may be broken down into the following three source categories. Sound radiation: This generally takes an airborne path. Mechanical vibrations: These generally extend For sound radiating from the compressor, the emission path is airborne and the sound waves are travelling directly from the machine in all directions. The VRJ scroll compressor is designed to be quiet and the frequency of the sound generated is pushed into the higher ranges, which not only are easier to reduce but also do not generate the penetrating power of lower-frequency sound. Due to this small re-expansion, there is no internal break mechanism required to prevent reverse spin of the scroll set. along the parts of the unit and structure. Gas pulsation: This tends to travel through the cooling medium, i.e. the refrigerant. The following sections will focus on the causes and methods of mitigation for each of the above sources. reducing the sound being transmitted to the outside. Ensure that no components capable of transmitting sound/vibration within the unit come into direct contact with any non-insulated parts on the walls of the unit. Because of the Danfoss unique design of a fullsuction gas & oil cooled motor, compressor body insulation across its entire operating range is possible. Use of sound-insulation materials on the inside of unit panels is an effective means of substantially 20 FRCC.PC.019.A2.22

21 Sound and vibration management Mechanical vibrations Speed bypass Gas pulsation Vibration isolation constitutes the primary method for controlling structural vibration. VRJ scroll compressors are designed to produce minimal vibration during operations. The use of rubber isolators on the compressor base plate is very effective in reducing vibration being transmitted from the compressor to the unit. Rubber grommets are supplied with all Danfoss compressors. Once the supplied rubber grommets have been properly mounted, vibrations transmitted from the compressor base plate to the unit are held to a strict minimum. In addition, it is extremely important that the frame supporting the mounted compressor be of sufficient mass and stiffness to help dampen any residual vibration potentially transmitted to the frame. The tubing should be designed so as If vibrations still occur at some typical frequencies, a speed bypass function is available within the VRJ. This function allows avoiding The VRJ scroll compressor has been designed and tested to ensure that gas pulsation has been optimised for the most commonly encountered air conditioning pressure ratio. On heat pump installations and other installations where the pressure ratio lies beyond the typical range, testing should be conducted under all expected to both reduce the transmission of vibrations to other structures and withstand vibration without incurring any damage. Tubing should also be designed for three-dimensional flexibility. During unit development, the complete compressor speed range should be covered, in order to define if abnormal vibrations occur or not. As ultimate solution, speed bypass can be applied. For more information on piping design, please see the section entitled Essential piping design considerations. some frequency ranges and avoiding vibrations to occur. Refer to Danfoss VRJ Installation and Operation instructions for setting details. conditions and operating configurations to ensure that minimum gas pulsation is present. If an unacceptable level is identified, a discharge muffler with the appropriate resonant volume and mass should be installed. This information can be obtained from the component manufacturer. FRCC.PC.019.A

22 Installation System cleanliness Compressor handling and storage Compressor mounting Compressor holding charge Tube brazing procedure Brazing material Each VRJ scroll compressor is shipped with printed Instructions for installation. The refrigerant compression system, regardless of the type of compressor used, will only provide high efficiency and good reliability, along with a long operating life, if the system contains solely the refrigerant and oil it was designed for. Any other substances within the system will not improve performance and, in most cases, will be highly detrimental to system operations. The presence of non-condensable substances and system contaminants, such as metal shavings, solder and flux, has a negative impact on compressor service life. Many of these contaminants are small enough to pass through a mesh screen and can cause considerable damage within a bearing assembly. The use of highly hygroscopic PVE oils in R410A compressors requires that the oil be exposed to the atmosphere just as little as possible. Compressors are provided with a lifting lug. This lug should always be used to lift the compressor. Once the compressor is installed, the lifting lug should never be used to lift the complete installation. The compressor must be handled Maximum inclination from the vertical plane, while operating must not exceed 7 degrees. All compressors are delivered with 4 rubber Each compressor is shipped with a nominal dry nitrogen holding charge between 6 psi and 10 psi, and is sealed with elastomeric plugs. The plugs should be removed with care to avoid oil loss when the holding charge is released. Remove the suction plug first and the discharge plug Do not bend the compressor discharge or suction lines or force system piping into the compressor connections, because this will increase For copper suction and discharge fittings, use copper-phosphorus brazing material. Sil-Fos and other silver brazing materials are also acceptable. System contamination is one of main factors affecting equipment reliability and compressor service life. It is important therefore to take system cleanliness into account when assembling a refrigeration system. During the manufacturing process, circuit contamination may be caused by: Brazing and welding oxides, Filings and particles from the removal of burrs in pipe-work, Brazing flux, Moisture and air. Consequently, when building equipment and assemblies, the following precautions must be taken: never drill holes into the pipe-work after installation. with caution in the vertical position, with a maximum inclination of 15 from vertical. Store the compressor between -30 F and 120 F, not exposed to rain or corrosive atmosphere. grommets and metal sleeves. Compressors must always be mounted with these grommets. afterwards. The plugs shall be removed only just before connecting the compressor to the installation in order to avoid moisture entering the compressor. When the plugs are removed, it is essential to keep the compressor in an upright position to avoid oil spillage. stresses that are a potential cause of failure. Recommended brazing procedures and material, are described on following page. If flux is required for the brazing operation, use coated rod or flux core wire. To avoid system contamination, do not brush flux on. 22 FRCC.PC.019.A2.22

23 Installation Compressor connection Vacuum evacuation and moisture removal When brazing the compressor fittings, do not overheat the compressor shell, which could severely damage certain internal components due to excessive heating. Use of a heat shield and/or a heat-absorbent compound is highly recommended. For brazing the suction and discharge connections, the following procedure is advised: Make sure that no electrical wiring is connected to the compressor. Protect the terminal box and compressor painted surfaces from torch heat damage (see diagram). Use only clean refrigeration-grade copper tubing and clean all connections. Purge nitrogen or CO2 through the compressor in order to prevent against oxidation and flammable conditions. The compressor should not be exposed to the open air for extended periods. Use of a double-tipped torch is recommended. Apply heat evenly to area A until the brazing temperature is reached. Move the torch to area B and apply heat evenly until the brazing temperature has been reached there as well, and then begin adding the brazing material. Move the torch evenly around the joint, in applying only enough brazing material to flow the full circumference of the joint. Move the torch to area C only long enough to draw the brazing material into the joint, but not into the compressor. Remove all remaining flux once the joint has been soldered with a wire brush or a wet cloth. Remaining flux would cause corrosion of the tubing. Moisture obstructs the proper functioning of both the compressor and the refrigeration system. Air and moisture reduce service life and increase condensing pressure, which causes abnormally high discharge temperatures that are then capable of degrading the lubricating properties of the oil. The risk of acid formation is also increased by air and moisture, and this condition can also lead to copper plating. All these phenomena may cause both mechanical Heat shield C B A Ensure that no flux is allowed to enter into the tubing or compressor. Flux is acidic and can cause substantial damage to the internal parts of the system and compressor. The PVE oil used in VRJ compressors is highly hygroscopic and will rapidly absorb moisture from the air. The compressor must therefore not be left open to the atmosphere for a long period of time. The compressor fitting plugs shall be removed just before brazing the compressor. Before eventual unbrazing the compressor or any system component, the refrigerant charge must be removed from both the high and low pressure sides. Failure to do so may result in serious personal injury. Pressure gauges must be used to ensure all pressures are at atmospheric level. For more detailed information on the appropriate materials required for brazing or soldering, please contact the product manufacturer or distributor. For specific applications not covered herein, please contact Danfoss Commercial Compressors for further information. and electrical compressor failures. The typical method for avoiding such problems is a vacuum pump-down executed with a vacuum pump, thus creating a minimum vacuum of 0.02 in Hg (500 µm Hg). Please refer to Bulletin Vacuum pump down and dehydration procedure. Be sure to follow all government regulations regarding refrigerant reclamation and storage. FRCC.PC.019.A

24 Installation Liquid line filter driers Refrigerant charging Insulation resistance and dielectric strength Compressor replacement after motor burn out A properly sized filter drier is required for all Danfoss scroll applications. Danfoss recommends DML (100% molecular sieves) driers for HFC refrigerants R410A with PVE oil. For servicing of existing installations where acid formation is present the Danfoss DCL solid core filter driers It is recommended that system charging be done using the weighed charge method, adding refrigerant to the high side of the system. Charging the high and low sides of a system with gas simultaneously at a controlled rate is also an acceptable method. Insulation resistance must be greater than 1 megohm when measured with a 500 volt direct current megohm tester. Each compressor motor is tested at the factory with a high potential voltage (hi-pot) that exceeds the UL requirement both in potential and in duration. Leakage current is less than 0.5 ma. VRJ scroll compressors are configured with the pump assembly at the top of the shell, and the motor below. As a result, the motor If there has been a motor burnout follow the evacuation procedure described on previous page. Remove and replace the liquid line filter drier and install a Danfoss type DAS burnout drier of appropriate capacity. containing activated alumina are recommended. The drier is to be over sized rather than under sized. When selecting a drier, always take into account its capacity (water content capacity), the system refrigeration capacity and the system refrigerant charge. Never exceed the recommended system charge mentioned by the unit manufacturer, and never charge liquid to the low pressure side. can be partially immersed in refrigerant and oil. The presence of refrigerant around the motor windings will result in lower resistance values to ground and higher leakage current readings. Such readings do not indicate a faulty compressor, and should not be cause for concern. In testing insulation resistance, Danfoss recommends that the system be first operated briefly to distribute refrigerant throughout the system. Following this brief operation, retest the compressor for insulation resistance or current leakage. Refer to the DAS drier instructions and technical information on correct use and monitoring of the burnout drier and the liquid line and suction line filter driers. 24 FRCC.PC.019.A2.22

25 Ordering information and packaging Packaging Single pack Compressors are packed individually in a cardboard box. They can be ordered in any quantity. Minimum ordering quantity = 1. As far as possible, Danfoss will ship the boxes on full pallets of 6 compressors. Each box contains following accessories: 4 grommets 4 assemblies of self tapping US thread bolts, washers and sleeves Industrial pack Compressors are not packed individually but are shipped all together on one pallet. They can be ordered in quantities of full pallets only, multiples 12 compressors. Industrial pack pallet, with mounting hardware, contains following accessories: Returnable pallet 4 grommets per compressor 4 sleeves per compressor As for industrial pack pallets, compressors are not packed individually but are shipped all together on one pallet. They can be ordered in quantities of full pallets only, multiples 16 compressors. Empty pallets must be returned to the compressor factory. Returnable pallets contain neither rubber grommets, nor sleeves. Ordering code numbers Code number Mounting hardware Compressor model included Qty of compressors 3 Tons 4 Tons 5 Tons VRJ028 VRJ035 VRJ044 Single pack Yes 1 121U U U7011 Industrial pack Yes U U U7008 Returnable pallet No U U U7010 FRCC.PC.019.A

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28 Danfoss Commercial Compressors is a worldwide manufacturer of compressors and condensing units for refrigeration and HVAC applications. With a wide range of high quality and innovative products we help your company to find the best possible energy efficient solution that respects the environment and reduces total life cycle costs. We have 40 years of experience within the development of hermetic compressors which has brought us amongst the global leaders in our business, and positioned us as distinct variable speed technology specialists. Today we operate from engineering and manufacturing facilities spread across three continents. Danfoss Turbocor Compressors Danfoss Inverter Scrolls Danfoss Scrolls Danfoss Optyma Condensing Units Danfoss Maneurop Reciprocating Compressors Secop Compressors for Danfoss Our products can be found in a variety of applications such as rooftops, chillers, residential air conditioners, heatpumps, coldrooms, supermarkets, milk tank cooling and industrial cooling processes. Danfoss Commercial Compressors, BP 331, Trévoux Cedex, France FRCC.PC.019.A November Replaces FRCC.PC.019.A October 2010 Copyright Danfoss Commercial Compressors