Motor Supply; Compressor Ambient Temperature; Application Envelope - Danfoss MLZ Selection & Application Manuallines

A
PPLICATION GUIDELINES

Motor supply

Compressor ambient
temperature
High ambient temperature
Low ambient temperature

Application envelope

O
PERATING CONDITIONS
MLZ / MLM scroll compressors can be operated at
nominal voltages as indicated on page 14. Under-
voltage and over-voltage operation is allowed
within the indicated voltage ranges. In case of
MLZ / MLM compressors can be applied from
-31°F to 122°F ambient temperature. The com-
pressors are designed as 100 % suction gas cooled
In case of enclosed fitting and high ambient tem-
perature it's recommend to check the temperature
of power wires and conformity to their insulation
specification.
Although the compressor itself can withstand low
ambient temperature, the system may require
specific design features to ensure safe and reli-
The operating envelopes for MLZ/MLM scroll
compressors are given in the figures below, where
the condensing and evaporating temperatures
represent the range for steady-state operation.
Under transient conditions, such as start-up and
defrost, the compressor may operate outside this
envelope for short periods.
The figures below show the operating envelopes
for MLZ compressors with refrigerants R404A/507,
160
140
Transient conditions
120
100
80
60
40
-30 -20 -10
FRCC.PC.016.A1.22
risk of under-voltage operation, special attention
must be paid to current draw and start assist for
single-phase compressors may be required.
without need for additional fan cooling. Ambient
temperature has very little effect on the compres-
sor performance.
In case of safe tripping by the internal compres-
sor overload protection the compressor must cool
down to about 140°F before the overload will re-
set. A high ambient temperature can strongly de-
lay this cool-down process.
able operation. See section 'Specific application
recommendations' .
R134a and R22. The operating limits serve to de-
fine the envelope within which reliable operations
of the compressor are guaranteed:
• Maximum discharge gas temperature: 275°F
• A suction superheat below 10°F is not recom-
mended due to the risk of liquid flood back
• Minimum and maximum evaporating and con-
densing temperatures as per the operating en-
velopes.
MLZ - R404A / R507
RGT: 65°F
0 10 20 30
Evaporating temperature (°F)
40 50 60
21