Danfoss VLZ065, Инструкции по применению

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Commissioning
Preliminary check
Check electrical power supply:
• Phase order: Reverse rotation is obvious if the
compressor do not build up pressure and sound
level is abnormal high. VLZ compressor will only
operate properly in one direction. If electrical
connections are done correctly between the
drive and the compressor terminals (compressor
terminals T1,T2,T3 and drive terminals U, V & W
matching), the drive will provide correct phase
supply to the compressor, and reverse rotation
will be not possible: For more details refer to
“Motor protection”.
• Voltage and voltage unbalance within tolerance:
For more details refer to section “Motor voltage”.
Initial start-up
System monitoring
• Crankcase heaters must be energized at least 6
hours in advance to remove refrigerant.
• 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 system must be monitored after initial
startup for a minimum of 60 minutes to ensure
proper operating characteristics such as:
• Proper metering device operation and desired
superheat readings
• Suction and discharge pressure are within
acceptable levels
• Correct oil level in compressor sump indicating
proper oil return
• Low foaming in sight glass and compressor
sump temperature 10K (18°F) above saturation
temperature to show that there is no refrigerant
migration taking place
• Acceptable cycling rate of compressors,
including duration of run times.
A short cycling protection is provided in the CDS
frequency converter. It is factory preset “enabled”
with the following parameters in:
28.01 - interval between 2 starts: 300 seconds
28.02 - minimum run time: 60 seconds.
This minimum run time is set to guaranty long
enough running time at start up in order to
create enough refrigerant flow velocity in the
system to recover the oil to the compressor
sump.
• Current draw of compressor within acceptable
values (RLA ratings)
• No abnormal vibrations and noise.
In installations with good oil return and line runs
up to 15 m (49 feet), no additional oil is required.
If installation lines exceed 15 m (49 feet),
additional oil may be needed. 1 or 2% of the total
system refrigerant charge (in kg) can be used to
roughly define the required oil top-up quantity
(in liters) but in any case, the oil charge has to be
adjusted based on the oil level in the compressor
sight glass.
When the compressor is running under stabilized
conditions, the oil level must be visible in the
sight glass.
The presence of foam filling in the sight glass
indicates large concentration of refrigerant in the
oil and / or presence of liquid returning to the
compressor.
The oil level can also be checked a few minutes
after the compressor stops, the level must be
between 1/4 and 3/4 of sight glass.
When the compressor is off, the level in the
sight glass can be influenced by the presence of
refrigerant in the oil.
Top-up the oil while the compressor is idle. Use
the Schrader connector or any other accessible
connector on the compressor suction line and
a suitable pump. See news bulletin “Lubricants
filling in instructions for Danfoss Commercial
Compressors” TI 2-025-0402.
Oil level checking and
top-up
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AB444226142054en-000101