1 – Introduction
These instructions pertain to the VLZ028-
VLZ044 variable scroll compressors used for air-
conditioning and reversible heat pump systems
in residential applications. They provide neces-
sary information regarding safety and proper us-
age of this product.
2 – Handling and storage
• Handle the compressor with care. Use the dedi-
cated handles in the packaging. Use the com-
pressor lifting lug and use appropriate and safe
lifting equipment.
• Store and transport the compressor in an up-
right position.
• Store the compressor between -35°C and 55°C
/ -31°F and 131°F.
• Don’t expose the compressor and the packag-
ing to rain or corrosive atmosphere.
3 – Safety measures before assembly
Never use the compressor in a flammable at-
mosphere.
• The compressor ambient temperature may
not exceed 55°C during off-cycle.
• Mount the compressor on a horizontal flat sur-
face with less than 7° slope.
• When installing a compressor model VLZ, use
equipment specifically reserved for HFC refrig-
erants, 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 vibra-
tions.
• The compressor must always be mounted using
the rubber grommets supplied with the com-
pressor.
4 – 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 de-
vices.
5 – 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 sys-
tem.
• 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.
6 – Vacuum dehydration
• Never use the compressor to evacuate the sys-
tem.
• 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.
7 – 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 lo-
cal regulations regarding power line protec-
tion.The compressor must be connected to
ground.
• Use 6.3 mm tabs for quick connect spade ter-
minals.
• 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) ter-
minals of compressor and drive U, V, W must
match. Please refer to drawings for typical wir-
ing connections and examine the specific wir-
ing diagram located in the frequency converter
package. For further details, refer to the appli-
cation guidelines.
• Mounting: The base frame of the frequency
converter must be very well fixed to the sup-
port 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
screeened design. The cable for electrical mo-
tor 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 mal-
functions.
An external overload is not necessary.
• Set the frequency converter parameters in
accordance with Danfoss recommendations
for the CDS803 frequency converter and VLZ
variable speed compressor.
• Refer to variable speed drive manual for electri-
cal connections details and installation.
• Compressor motor protection is provided by
the variable speed drive.
8 – 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 pres-
sure operation and excessive superheat. For
VLZ028-044, the refrigerant charge limit is
3.6kg.Above this limit; protect the compressor
against liquid flood-back with a pump-down
cycle not lower than 1.1 bar(g) for R448A/1.1
bar(g) for R449A/ 1.6 bar(g) for R404A or a suc-
tion line accumulator.
• Never leave the filling cylinder connected to
the circuit.
9 – Verification before commissioning
Use safety devices such as safety pressure
switch and mechanical relief valve in compli-
ance 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.
Refrigerant
R448A R449A R404A
Min. low pressure
safety switch setting
bar(g) 0.8
0.8
1.3
• Verify that all electrical connections are prop-
erly fastened and in compliance with local
regulations.
• When using a dome sensor, ensure the dome
sensor is correctly installed and fitted into
bracket on top of the shell. The sensor need
to be well connected, especially after mainte-
nance operations.
• After comissioning it is strongly recommended
to keep the frequency converter always ener-
gized.
10 – Start-up
• Never start the compressor when no refriger-
ant is charged.
• Do not provide any power to the drive unless
suction and discharge service valves on com-
pressor 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 con-
formity.
• 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 particu-
lar the combination of compressor, frequency
converter and refrigerant.
Instructions
© Danfoss | DCS (CC) | 2017.07 | 3
8510286P01B - FRCC.PI.039.A3.02
