Operating conditions
SM084 to 185
SY185 to 380
R22
Motor supply
SM / SY / SZ scroll compressors can be operated
at nominal voltages as indicated on “Motor
voltage code” section. 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 SM / SY / SZ
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 refrigerants R22, R407C, R134a, R404A, R507
and R513A.
The operating limits serve to define the
envelope within which reliable operations of the
compressor are guaranteed:
• Maximum discharge gas temperature: +135°C
• A suction superheat below 5 K (10 K for R407C)
is not recommended due to the risk of liquid
flood back
• Maximum superheat of 30 K
• Minimum and maximum evaporating and
condensing temperatures as per the operating
envelopes.
SM / SY / SZ compressors can be applied from
-35°C to +63°C (for SM/SZ084 to 185) and +53°C
(for SY/SZ 240 to 380) 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 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 at
dew temperatures
Compressor ambient
temperature
High ambient temperature
Low ambient temperature
70
65
60
55
50
45
40
35
30
-25
-20
-15
-10
-5
0
5
10
15
20
Condensing t
emper
atur
e (°C
)
Evaporating temperature (°C)
S.H. = 30 K
SUPERHEAT
S.H. = 11.1 K
S.H. = 5 K
26
AB237986441643en-010801
Application Guidelines
Summary of Contents for R134a
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