Danfoss R22 - Motor Supply; Compressor Ambient Temperature; Application Envelope at Dew Temperatures

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 page 18.
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 gures
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 gures below show the operating envelopes
for SM / SY compressors with refrigerants R22
and for SZ compressors with R407C, R134a,
R404A and R507C.
The operating limits serve to dene the
envelope within which reliable operations of the
compressor are guaranteed:
• Maximum discharge gas temperature: 275°F
• A suction superheat below 9°F (18°F for R407C)
is not recommended due to the risk of liquid
ood back
• Maximum superheat of 54°F
• Minimum and maximum evaporating and
condensing temperatures as per the operating
envelopes.
SM / SY / SZ compressors can be applied from
-31°F to 145.4°F (for SM/SZ084 to 185) and 127.4°F
(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 eect on the
compressor performance.
In case of enclosed tting and high ambient
temperature it’s recommend to check the
temperature of power wires and conformity to
their insulation specication.
In case of safe tripping by the compressor
overload protection the compressor must cool
down to about 140°F 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 specic design features to ensure safe
and reliable operation. See section ‘Specic
application recommendations’.
Application envelope at dew
temperatures
Compressor ambient
temperature
High ambient temperature
Low ambient temperature
80
90
100
110
120
130
140
150
160
-10 0 10 20 30 40 50 60
Condensing temperature (°F)
Evaporating temperature (°F)
S.H. = 54°F SUPERHEAT
S.H. = 20°F
S.H. = 9°F
Application guidelines
26
FRCC.PC.003.A5.22