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Vol. 2.6 © 2020 Hanbell Precise Machinery Co., Ltd. All rights reserved
Oil pressure in the oil tank
Pressure in the oil tank must be kept as low as possible for oil return to the oil tank finally.
A pipe is connected between the oil tank and the suction casing (item 15 in Figure 4.4).
Therefore, in normal condition the pressure difference between oil tank and suction side
is-0.2~0.5bar.
Note
：
1. If oil pressure is abnormal inside the oil tank, the possible cause might be that the
labyrinth ring for separating high/ low pressure is damaged and a large amount
of refrigerant leak as shown in Figure 4.6.
2. When the oil tank pressure (P3) is 0.6 kg/cm² higher than the suction pressure
(Ps), system should provide an alarm signal
to users. When the oil tank pressure is 0.8
kg/cm² higher than the suction pressure,
system should be stopped for protection
and troubleshooting.
P3-Ps
≧
≧
≧
≧
0.6kgf/cm
2
22
2
alarm
P3-Ps
≧
≧
≧
≧
0.8kgf/cm
2
22
2
shut down
Figure 4.6 L a b yrin t h rin g
RT series compressors are equipped with rigid bearings and fine oil separators.
Therefore, oil carry-over in the system is much less. For oil return from the evaporator,
orifice size of the oil return outlet of the evaporator should be confined. Suggested orifice
sizes are shown as the table as below. Too much liquid refrigerant will cause poor
lubrication for bearings resulting in serious damage to the compressor.
Model
Size of orifice
RT-120~140
RT-111
φ
2
RT-160~200
RT-221, 161
φ
3
RT-240~280
φ
4
Unit: mm
