Application Guidelines
22
AB141686422149en-US0401
Installation
Liquid line filter driers
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
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.
Refrigerant charging
Insulation resistance and
dielectric strength
Compressor replacement
after motor burn out
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.
Never exceed the recommended system charge
mentioned by the unit manufacturer, and never
charge liquid to the low pressure side.
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
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.
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.
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.
Summary of Contents for VRJ
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