Operating conditions
Motor supply
MLZ/MLM scroll compressors can be operated at
nominal voltages as indicated in the table in the
section “Motor voltage”. Under-voltage and over-
voltage operation is allowed within the indicated
voltage ranges. In case of risk of under-voltage
operation, special attention must be paid to
current draw.
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/MLM compressors with refrigerants
R404A and R22. The operating limits serve
to define the envelope within which reliable
operations of the compressor are guaranteed:
• Maximum discharge gas temperature: +135°C.
• Minimum suction superheat should be above
5 K due to the risk of liquid flood-back.
• Attention to suction line insulation to reduce
unuseful superheat.
• Minimum and maximum evaporating and
condensing temperatures as per the operating
envelopes.
MLZ/MLM compressors can be applied from
-35°C to 55°C ambient temperature. The
compressors are designed as 100% suction gas
cooled without need for additional fan cooling.
Ambient temperature has very little effect on the
compressor performance.
In case of enclosed fitting and high ambient
temperature it’s recommend to check the
temperature of power wires and conformity to
their insulation specification.
In case of safe tripping by the internal
compressor overload protection the compressor
must cool down to about 60°C before the
overload will reset. A high ambient temperature
can strongly delay this cool-down process.
Although the compressor itself can withstand
low ambient temperature, the system may
require specific design features to ensure safe
and reliable operation. See section ‘Specific
application recommendations’.
Application envelope
Compressor ambient
temperature
High ambient temperature
Low ambient temperature
MLZ116 - R404A
RGT: +20°C
Superheat: 10 K
Condensing t
emp
er
atur
e (°C
)
Evaporating temperature (°C)
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
5
10
15
20
25
30
35
40
45
50
55
60
65
19
FRCC.PC.035.A5.02
Application Guidelines
Single compressors
