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The Danfoss VZH028-VZH065 series comprises variable speed inverter compressors designed for air-conditioning and reversible heat pump systems in residential applications. These compressors are powered by a dedicated variable speed drive, which can be either a Danfoss drive or a third-party drive. When a Danfoss drive is selected, compatibility between the compressor model and the variable speed drive must be carefully checked.
These compressors utilize inverter technology to vary their speed, allowing for precise control over cooling or heating capacity. This variable speed operation contributes to improved energy efficiency and enhanced comfort by maintaining more stable temperatures. The compressors are designed to operate within specific limits of temperature and speed, which are secured by parameters in the drive and application controller software.
The compressors operate with R410A refrigerant. The model number, serial number, refrigerant type, manufacturing year, supply voltage range (380-480V3~50/60Hz for VZH044CGANA, 400-460V/208-230V for operating maps), maximum operating current, and lubricant type (PVE) and nominal charge are indicated on the compressor's nameplate.
Electrical connections vary by model: VZH028-044 models use quick-connect spade terminals, while VZH052-065 models use ring-connect screw terminals (C & Q terminal box type). The compressor motor cable must be shielded and grounded at both ends (compressor side and frequency converter side) using an EMC cable gland for proper grounding and conductivity.
Operating limits are defined by condensing and evaporating temperatures, as well as compressor speed (RPM). For VZH028-044, operating maps show speeds ranging from 900-6000 rpm, with condensing temperatures up to 75°C and evaporating temperatures from -40°C to 35°C. For VZH052-065, speeds range from 1000-6600 rpm, with similar temperature ranges. The maximum allowed suction superheat is 30K, with an optimum of around 6K. The maximum compressor test pressure for the low side is 30 bar for VZH028-044 and 33.3 bar for VZH052-065; for the high side, it is 41.1 bar. The maximum pressure difference between high and low sides is 36 bar.
Refrigerant charge limits are 3.6 kg for VZH028-044 and 5.4 kg for VZH052-065. Above these limits, protection against liquid flood-back is required, either through a pump-down cycle (minimum 1.18 bar(g) for VZH028-044 / 1.8 bar(g) for VZH052-065) or a suction line accumulator.
The compressors are designed for use with HFC refrigerants and require dedicated equipment that has not been used for CFC or HCFC refrigerants. Clean, dehydrated refrigeration-grade copper tubes and silver alloy brazing material, along with clean and dehydrated system components, are essential for proper installation.
A low-pressure safety switch is mandatory to prevent vacuum operation, with minimum settings of 1.0 bar(g) for VZH028-044 and 1.5 bar for VZH052-065. A discharge temperature sensor, if used, must be correctly installed and fitted to the discharge piping (6 inches from the discharge fitting).
The compressor must be mounted on a horizontal flat surface with less than a 7º slope, using the supplied rubber grommets to dampen vibrations. Piping connected to the compressor must also be flexible in 3 dimensions.
Start-up procedures include slowly releasing the nitrogen holding charge, connecting the compressor to the system promptly to avoid oil contamination, and ensuring no material enters the system during tube cutting. The drive must be energized only when suction and discharge service valves are open. The compressor will start according to defined ramp-up settings. During initial start-up, it is crucial to verify correct rotation direction to ensure proper pumping and avoid issues like excessive noise or lack of pressure differential. A 300-second period is required between starts, and the minimum running time is 12 seconds per start.
Periodic service inspections are recommended to ensure system reliability and compliance with local regulations. This includes verifying safety devices, checking for leaks, monitoring compressor current draw (via Modbus), and confirming consistent system operation with previous maintenance records. Electrical connections should be adequately fastened, and the compressor shell, tubes, and electrical connections should be kept clean and free of rust and oxidation. Regular checks of acid/moisture content in the system and oil are also recommended.
The number of compressor cycles should not exceed 12 starts per hour to prevent short cycling. Internal pressure and surface temperature can be dangerous, so maintenance must be performed by qualified personnel wearing protective goggles and work gloves. The compressor is delivered under nitrogen gas pressure (0.3-0.4 bar / 4-6 psi), and this pressure must be relieved before disassembling any components.
In case of warranty claims, the model number and serial number must always be provided. The fault memory of the frequency converter can be used to recover fault descriptions. Warranty may be voided by the absence of a nameplate, external modifications, an opened or unsealed compressor, rust/water/leak detection dye inside the compressor, use of unapproved refrigerant or lubricant, deviations from recommended installation/application/maintenance instructions, use in mobile applications, use in explosive atmospheric environments, or failure to transmit model/serial numbers with the claim. Compressors and compressor oil should be recycled by a suitable company at their site.
General| Brand | Danfoss |
|---|---|
| Model | VZH028 |
| Category | Air Compressor |
| Language | English |
