Danfoss VLZ028 Scroll Inverter Compressors Instructions

VLZ028 Scroll Inverter Compressors
Instructions

VLZ028 Scroll Inverter Compressors

1. Model number
2. Serial Number
3. Refrigerant
4. Manufacturing year
5. Supply voltage range
6. Max operating current
7. Lubricant type and nominal charge

Operating limits

All the above limits, temperatures and speeds, are secured by parameters in the drive and application controller softwares.

Electrical connections

VLZ028 – VLZ065 compressors can be powered by the dedicated variable speed drive.
When Danfoss drive is selected, check carefully for compatibility between compressor model and variable speed drive.

* China region only

Installation and servicing of the compressor by qualified personnel only. Follow these instructions and sound refrigeration engineering practice relating to installation, commissioning, maintenance and service.
The compressor must only be used for its designed purpose(s) and within its scope of application (refer to «operating limits»). Consult Application guidelines and datasheet available from cc.danfoss.com
Never operate compressorwithout terminal box cover in place and secured.
Under all circumstances, the EN378 (or other applicable local safety regulation) requirements must be fulfilled. Wear protective goggles and work gloves.
The compressor must be handled with caution in the vertical position (maximum offset from the vertical : 15°).
The compressor is delivered under nitrogen gas pressure (between 0.3 and 0.4 bar / 4 and 6 psi). Do not disassemble bolts, plugs, fittings, etc… unless all pressure has been relieved from the compressor.

Basic connections

• Depending on the frequency converter version, the physical position of individual connectors may differ from below diagram.
• Always make sure that the compressor terminals T1, T2, T3 are connected to the frequency converter terminals U, V, W respectively.
• The compressor motor cable must be shielded and the armoured part must be connected to ground on both cable ends; at the side of the compressor and at the side of the frequency converter.
• Use an EMC cable gland for cable installation and perfect grounding; The metallic terminal box of the compressor has a paint-free surface around the connection hole for better conductivity.
• A low pressure safety switch is mandatory to avoid compressor vacuum operation.
• At start-up, verify that the compressor rotates in the right direction and pumps.

Oil level switch assembly

Install the screw-in optical part on oil level switch port. (Factory preset for manifold version VLZ compressor.)| Install the electrical part on optical part. Make sure the cable outlet downside vertically.

• For LC-PR, make sure the cable outlet downside or upside vertically.

Electrical connections/Wiring for Oil level sensor
See at the correct diagram corresponding to different power supply models for proper wiring

1. Power supply wire
2. Power supply wire
3. Output wire
4. Not used

1. Power supply (L or 24V)
2. Output NO CONTACT
3. Power supply (N or 0V)
4. Output COMMON

Introduction

These instructions pertain to the VLZ028-VLZ065 variable scroll compressors used for refrigeration systems. They provide necessary information regarding safety and proper usage of this product.

Handling and storage

• Handle the compressor with care. Use the dedicated handles in the packaging. Use the compressor lifting lug and use appropriate and safe lifting equipment.
• Store and transport the compressor in an upright position.
• Store the compressor between -35°C and 55°C/-31°F and 131°F.
• Don’t expose the compressor and the packaging to rain or corrosive atmosphere.

Safety measures before assembly

Never use the compressor in a flammable atmosphere.

• The compressor ambient temperature may not exceed 50°C during off-cycle.
• Mount the compressor on a horizontal flat surface with less than 7° slope.
• When installing a compressor model VLZ, use equipment specifically reserved for HFC refrigerants, which was never used for CFC or HCFC refrigerants.
• Use clean and dehydrated refrigeration-grade copper tubes and silver alloy brazing material.
• Use clean and dehydrated system components.
• The piping connected to the compressor must be flexible in 3 dimensions to dampen vibrations.
• The compressor must always be mounted using the rubber grommets supplied with the compressor.

Assembly

• Slowly release the nitrogen holding charge through discharge and suction ports.
• Connect the compressor to the system as soon as possible to avoid oil contamination from ambient moisture.
• Avoid material entering into the system while cutting tubes. Never drill holes where burrs cannot be removed.
• Braze with great care using state-of-the-art technique and vent piping with nitrogen gas flow.
• Connect the required safety and control devices.

Leak detection
Never pressurize the circuit with oxygen or dry air. This could cause fire or explosion.

• Do not use leak detection dye.
• Perform a leak detection test on the complete system.
• The low side test pressure must not exceed 31 bar/450 psi.
• When a leak is discovered, repair the leak and repeat the leak detection.

Vacuum dehydration

• Never use the compressor to evacuate the system.
• Connect a vacuum pump to both the LP & HP sides.
• Pull down the system under a vacuum of 500 µm Hg (0.67 mbar) / 0.02 inch Hg absolute.
• Do not use a mega ohmmeter nor apply power to the compressor while it is under vacuum as this may cause internal damage.

Electrical connections

• Switch off and isolate the main power supply.
• Before touching any potentially live part of the drive, wait at least 4 minutes.
• The compressor is protected against excess current by the frequency converter. Follow local regulations regarding power line protection.The compressor must be connected to ground.
• Use 6.3 mm tabs for quick connect spade terminals.
• Use a self-tapping screw to connect the ground conductor to the compressor.
• Care must be taken during installation to ensure that the compressor operates in the correct direction. T1 (U), T2 (V) and T3 (W) terminals of compressor and drive U, V, W must match. Please refer to drawings for typical wiring connections and examine the specific wiring diagram located in the frequency converter package. For further details, refer to the application guidelines.
• Mounting: The base frame of the frequency converter must be very well fixed to the support to ensure a very good continuity between the ground potential of all electrical panels and electrical boxes of the system.
• Wiring: All control wires have to be of a screened design. The cable for electrical motor supply has to be of a shielded design as well. Correct earthing of the shield cover has to be done using the method shown on drawings, every time this one has to be earthed on each end of the cables. Distinct cable trays must be used for control and motor supply.
• The frequency converter ensures direct motor protection and the factory set parameters are such to protect the motor over all current malfunctions. An external overload is not necessary.
• Set the frequency converter parameters in accordance with Danfoss recommendations for the frequency converter and VLZ variable speed compressor.
• Refer to variable speed drive manual for electrical connections details and installation.
• Compressor motor protection is provided by the variable speed drive.

Filling the system

• Keep the compressor switched off.
• Fill the refrigerant in liquid phase into the outlet of the condenser or the liquid receiver. The charge must be as closed as possible to the nominal system charge to avoid low pressure operation and excessive superheat. For VLZ028-044, the refrigerant charge limit is 3.6 kg, Pump down switch setting should be not lower than 1.0 bar(g) for R448A/1.0 bar(g) for R449A/1.5 bar(g) for R404A.
• Never leave the filling cylinder connected to the circuit.

Verification before commissioning
Use safety devices such as safety pressure switch and mechanical relief valve in compliance with both generally and locally applicable regulations and safety standards. Ensure that they are operational and properly set.
Check that the settings of high-pressure switches do not exceed the maximum service pressure of any system component.

• A low-pressure switch is mandatory to avoid vacuum operation. Minimum setting 0.8 bar(g) for R448A/R449A. Minimum pressure 1.3 bar(g) for R404A.
• Verify that all electrical connections are properly fastened and in compliance with local regulations.
• When using discharge temperature sensor, ensure that the discharge temperature sensor is correctly installed and fitted to the discharge piping (6 inches from discharge fitting) and well connected, especially after maintenance operations.
• After comissioning it is strongly recommended to keep the frequency converter always energized.

Start-up

• Never start the compressor when no refrigerant is charged.
• Do not provide any power to the drive unless suction and discharge service valves on compressor are open, if installed.
• Energize the drive. The compressor must start, according to defined ramp-up settings. If the compressor does not start, check wiring conformity.
• Check the frequency converter control panel: If any alarm is displayed check the wiring and in particular the polarity of the control cables. If an alarm is shown, refer to the frequency converter application manual. Verify in particular the combination of compressor, frequency converter and refrigerant.
• Check current draw and voltage levels on the mains. The values for the compressor electrical motor can be directly displayed on the frequency converter control panel.
• The optimum compressor suction superheat is around 10K.
• Eventual reverse rotation can be detected by following phenomena; the excessive noise, no pressure differential between suction and discharge, and line warming rather than immediate cooling. A service technician should be present at initial start-up to verify that wiring from drive to compressor is properly phased and that the compressor is rotating in the correct direction.
• Note that a 300 seconds period is necessary between 2 starts, a shorter period will be not allowed by the drive. The minimum running time is 12s for each start.

Check with running compressor
Check current draw and voltage. Measurement of amps and volts during running conditions must be taken at other points in the power supply, not in the compressor electrical box.

• Check suction superheat to reduce risk of slugging.

• Observe the oil level at start and during operation to confirm that the oil level remains visible. Excess foaming in oil sight glass indicates refrigerant on the sump.

• Monitor the oil sight glass for 1 hour after system equilibrium to ensure proper oil return to the compressor. This oil check has to be done over the speed range to guarantee:
  – a good oil return at low speed with minimum gas velocity.
  – a good oil management at high speed with maximum oil carry over.

• Respect the operating limits.

• Check all tubes for abnormal vibration. Movements in excess of 1.5 mm/0.06 inch require corrective measures such as tube brackets.

• When needed, additional refrigerant in liquid phase may be added in the low-pressure side as far as possible from the compressor. The compressor must be operating during this process.

• Do not overcharge the system.

• Never release refrigerant to atmosphere.

• Before leaving the installation site, carry out a general installation inspection regarding cleanliness, noise and leak detection.

• Record type and amount of refrigerant charge as well as operating conditions as a reference for future inspections.

• Compressor failure to build up pressure: Check all bypass valves in the system to ensure that none of these has been opened. Also check that all solenoid valves are in their proper position.

• Abnormal running noise: Ensure the absence of any liquid flood-back to the compressor by means of measuring the return gas superheat and compressor sump temperature. The sump should be at least 10K above the saturated suction temperature under steady-state operating conditions.

• The high-pressure switch trips out: Check condenser operations (condenser cleanliness, fan operation, water flow and water pressure valve, water filter, etc.). If all these are OK, the problem may be due to either refrigerant overcharging or the presence of a noncondensable (e.g. air, moisture) in the circuit.

• The low-pressure switch trips out: Check evaporator operations (coil cleanliness, fan operations, water flow, water filter, etc.), liquid refrigerant flow and pressure drops (solenoid valve, filter dryer, expansion valve, etc.), refrigerant charge.

• Low refrigerant charge: The correct refrigerant charge is given by the liquid sight glass indication, the condenser delta T in relation to the refrigerant pressure tables (pressuretemperature), the superheat and the subcooling, etc. (if additional charge is deemed necessary, refer to section 8).

• Compressor short cycling: The number of cycles shall never exceed 12 starts per hour.

Maintenance

Internal pressure and surface temperature are dangerous and may cause permanent injury. Maintenance operators and installers require appropriate skills and tools. Tubing temperature may exceed 100°C / 212°F and can cause severe burns.
Ensure that periodic service inspections to ensure system reliability and as required by local regulations are performed. To prevent system related compressor problems, following periodic maintenance is recommended:

• Verify that safety devices are operational and properly set.
• Ensure that the system is leak tight.
• Check the compressor current draw by reading one of the parameters via Modbus.
• Confirm that the system is operating in a way consistent with previous maintenance records and ambient conditions.
• Check that all electrical connections are still adequately fastened.
• Keep the compressor clean and verify the absence of rust and oxidation on the compressor shell, tubes and electrical connections.
• Acid/moisture content in system and oil should be checked regularly.

Warranty

Always transmit the model number and serial number with any claim filed regarding this product.
Use the fault memory of the frequency converter to recover the fault descriptions before initializing the system and even before shutting off the power.
Variable speed drive model and serial number must also be transmitted with the claim. The product warranty may be void in following cases:

• Absence of nameplate.
• External modifications; in particular, drilling, welding, broken feet and shock marks.
• Compressor opened or returned unsealed.
• Rust, water or leak detection dye inside the compressor.
• Use of a refrigerant or lubricant not approved by Danfoss.
• Any deviation from recommended instructions pertaining to installation, application or maintenance.
• Use in mobile applications.
• Use in explosive atmospheric environment.
• No model number or serial number transmitted with the warranty claim.

Disposal
Danfoss recommends that compressors and compressor oil should be recycled by a suitable company at its site.

Any information, including, but not limited to information on selection of product, its application or use, product design, weight, dimensions, capacity or any other technical data in product manuals, catalogues descriptions, advertisements, etc. and whether made available in writing, orally, electronically, online or via download, shall be considered informative, and is only binding if and to the extent, explicit reference is made in a quotation or order confirmation. Danfoss cannot accept any responsibility for possible errors in catalogues, brochures, videos and other material. Danfoss reserves the right to alter its products without notice. This also applies to products ordered but not delivered provided that such alterations can be made without changes to form, fit or function of the product.
All trademarks in this material are property of Danfoss A/S or Danfoss group companies. Danfoss and the Danfoss logo are trademarks of Danfoss A/S. All rights reserved.

Danfoss A/S Climate Solutions
danfoss.com
+45 7488 2222
8510286P01AA- AN280556890612en-000201

References

• Read more on our commercial compressors | Danfoss | Danfoss

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