Oil separator below compressor level

The safest arrangement: Install the oil separator below the compressor level and lay the discharge gas line with a downward gradient (see following figure). This ensures that oil can drain out of the discharge gas side of the compressor towards the oil separator even during standstill.

Example for HS.53 to 74:

Arrangement of oil separator, discharge gas line and oil injection line with oil separator below compressor level. The picture shows an HS. compressor, but applies analogously to OS. compressors. For OS.A compressors with R717 (ammonia), see Technical Information AT-640.

Example for HS.85:

Arrangement of oil separator, discharge gas line and oil injection line with oil separator below compressor level, example with HS.85 compressor. It is recommended that the discharge gas line from the compressor to the oil separator be installed with some gradient – horizontal laying as shown here is a borderline case, because no oil should flow back into the compressor.

Legend for refrigerant circuit HS./OS.53 to 85 (except with R717)
Legend
1	Compressor
2	Oil solenoid valve
3	Oil flow switch
4	Oil filter
5	Standstill bypass (if required)
6	Oil separator with heating and oil level switch
7	Differential pressure valve (if required)
8	Water cooled oil cooler (if required)
9	Condenser
10	Air cooled oil cooler
11	Oil pump (if required)
12	Mixing valve (if required)
	Suction gas filter
	Sight glass
	Control valve
	Solenoid valve
	Check valve
	Shut-off valve
PRV	Pressure regulating valve
LZ	Level monitor
FZ	Flow limiter
PC	Pressure-controlled
TC	Temperature-controlled

Legend contains connection positions that do not appear in every diagram.

For single compressors, a standstill bypass should also lead from the inlet of the oil separator to the suction side of the compressor. Detailed description: Standstill bypass for oil separator.

Only pipe bends with large radii should be used for oil lines and there should be few deflections. The oil solenoid valve must be close to the injection point and correctly dimensioned. This also applies to the following versions.