Operating conditions
Motor supply
CH scroll compressors can be operated at
nominal voltages as indicated 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 CH scroll
compressors is given in the figure 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 operating
limits serve to define the envelope within
which reliable operations of the compressor are
guaranteed:
• Maximum discharge gas temperature: +135°C,
• Due to the risk of liquid flood back the minimum
suction superheat allowed is 5 K
• Maximum superheat of 30 K,
• Minimum and maximum evaporating and
condensing temperatures as per the operating
envelopes.
CH compressors can be applied from -35°C to
51°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.
Application envelope
Compressor ambient
temperature
POE oil
Polyolester oil (POE) is miscible with HFC's
(while mineral oil is not), but has to be evaluated
regarding lubrication ability in compressors.
POE oil has better thermal stability than
refrigerant 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 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’.
High ambient temperature
Low ambient temperature
10
-10
5
0
15
-5
20
25
30
35
40
37.8
26.7
-23.3
1.7 4.4
12.8
-26.1
45
50
55
60
65
70
75
80
85
-35
-40
-45
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
Evaporating temperature (°C)
Condensing temperature
(°C
)
SH 10K
SH 5K
Map CH290
19
FRCC.PC.026.A4.02
Application Guidelines
