Parallel compound CS.
CS. and CSV. compressors can also be operated in parallel. In this case, an additional oil separator and two oil level monitors (OLC) are required on each of the compressors. The oil separator designated as secondary oil separator is installed as a primary separator (e.g. BITZER OA series), designed via the displacement - as for the common oil separator in parallel compounds of HS. compressors. The superior control system must be provided by the contractor.
If the oil level monitoring (OLC) on a compressor indicates the minimum oil level, oil from the oil separator is fed back to this compressor until the maximum oil level (OLCmax) is reached.
In the figure above, the two CS. compressors have a common high-pressure side, the evaporator has two circuits. As a variant, two CS. compressors can also be operated with one evaporator to enable lower part loads.
If oil remains in the evaporator at low part load over a long operating time, a classic oil purge circuit (oil return function) must also be integrated (full load operation of the compressor to increase the flow velocity and return the oil from the evaporator to the compressor). This oil return function could take place via OLCmin of the oil separator (and possibly OLCmin of the compressor in operation) - in this case, the system must be operated with more power, e.g. by setting the slider of the running compressor to CR 100%.
WARNINGDanger of liquid slugging!
The compressor that is fed oil from the oil separator back into the ECO connection must be in operation.