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3.7
Discharge gas temperature protection
IMPORTANT
Inadequate lubrication! Scroll set damage! All YRH(V)*KTE/KTG
compressors must be equipped with a discharge gas temperature protection.
A good system control shall prevent the system from operating outside the published operating
envelope and acceptable superheat range, whatever the climatic conditions and the capacity
demand. However, under some extreme operating conditions (such as loss of charge or improper
control operation), the internal discharge gas temperature reached can cause compressor damage.
In order to ensure positive compressor protection, a discharge gas temperature protection sensor is
required for any application with Copeland brand compressors.
The maximum discharge gas temperature is 120 °C for all YRH(V)*KTE/KTG horizontal scroll
compressors.
3.7.1 External discharge line temperature sensor
The use of an external discharge sensor is required for all YRH(V)*KTE/KTG horizontal compressors.
Assembly of the discharge line sensor
To ensure proper functioning and to avoid false readings, the discharge line sensor must be installed
and insulated according to the procedure and recommendations hereunder.
▪ Install the discharge line sensor on the discharge tube 120 mm from the top cap.
▪ The sensor should be placed on the discharge tube in upward position.
▪ The wire must not be in contact with the top cap of the compressor or the discharge tube. Care
should be taken to route the wires so that they do not touch sharp objects.
▪ To avoid any impact on tripping temperature by the ambient, the discharge line sensor must be
properly insulated.
Figure 10: Discharge line sensor with insulation
3.8
Internal pressure relief valve
YRH(V)*KTE/KTG horizontal scroll compressors do not have any internal pressure relief valve. To
ensure safe operation, a high-pressure control must be used in all applications.
3.9
Discharge check valve
YRH(V)*KTE/KTG horizontal scroll compressors contain an internal check valve on the discharge
connection. The check valve prevents rapid discharge to suction pressure equalisation but it is not
entirely gas-tight.
Emerson recommends adding a gas-tight external check valve in the discharge line of the
YRH(V)*KTE/KTG compressors in transport applications, to avoid liquid refrigerant migration into the
compressor during standstill. The external check valve must be qualified for operation in the
discharge line.
3.10 Filter screens
CAUTION
Screen blocking! Compressor breakdown! Use screens with at least
0.6 mm openings.
The use of filter screens finer than 30 x 30
be avoided with these compressors. Field experience has shown that finer mesh screens used to
protect thermal expansion valves, capillary tubes or accumulators can become temporarily or
AGL_AC_ST_YRH_EN_Rev01
mesh
(0.6 mm openings) anywhere in the system should
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