APPLICATION GUIDELINES
FRCC.PC.007.B5.02
25
OPERATING CONDITIONS
Motor supply SH scroll compressors can be operated at nomi-
nal voltages as indicated section "Motor volt-
age". 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 envelope for SH scroll compressors
is given in the fi gure below, where the condens-
ing and evaporating temperatures represent the
range for steady-state operation. Under transient
conditions, such as start-up and defrost, the com-
pressor may operate outside this envelope for
short periods.
The operating limits serve to defi ne the envelope
within which reliable operations of the compres-
sor are guaranteed:
• Maximum discharge gas temperature: +135°C,
• A suction superheat below 5 K is not recom-
mended due to the risk of liquid fl ood back,
• Maximum superheat of 30 K,
• Minimum and maximum evaporating and con-
densing temperatures as per the operating
envelopes.
SH compressors can be applied from -35°C to 55°C
ambient temperature for SH090-105-120-140-161-
184 and 51°C ambient temperature for SH180-
240-300-380. The compressors are designed as
100 % suction gas cooled without need for addi-
tional fan cooling. Ambient temperature has very
little eff ect on the compressor performance.
Application envelope
Compressor ambient
temperature
10
15
20
25
30
35
40
45
50
55
60
65
70
75
-35 -30 -25 -20 -15 -10 -5 0 5 10 15 20
Evaporating temperature (°C)
Condensing temperature (°C)
SH = 11.1 K
SH = 5 K
POE oil Polyolester oil (POE) is miscible with HFC's (while
mineral oil is not), but has to be evaluated regard-
ing lubrication ability in compressors.
POE oil has better thermal stability than refriger-
ant mineral oil.
POE is more hygroscopic and also holds moisture
more tight than mineral oil.
It also chemically reacts with water leading to acid
and alcohol formation.
In case of enclosed fi tting and high ambient tem-
perature it’s recommend to check the tempera-
ture of power wires and conformity to their insu-
lation specifi cation.
In case of safe tripping by the internal compres-
sor 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
specifi c design features to ensure safe and reli-
able operation. See section ‘Specifi c application
recommendations’.
High ambient temperature
Low ambient temperature
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