Precautions For Refrigerant Cycle Design - Hitachi CA47TLA-D2PE3 Manual

1-2．PRECAUTIONS FOR REFRIGERANT CYCLE DESIGN
(1) Oil Return and Oil Quantity
*The refrigerant cycle should be so designed that the oil return to the compressor should
always be secured, and oil should not accumulate.
*The compressor should be operated by keeping the shaft horizontal, but in reality the
compressor should be operated with a maximum of 5.6 degrees (9.8%) inclination in all
directions. The minimum oil contained in the compressor in this case should be the values
stated in Table 1-1 or higher.
However, this oil quantity does not consider the fluctuation of the oil surface when the
inclination exceeds 5.6 degrees (9.8%), or the train or bus starts or stops abnormally.
Table 1-1 Minimum Oil Quantity
φ 160 series
φ 190 series
*The compressor should be installed vertically to the moving direction of the train or bus as
shown in Figure 1-1.
*This minimum oil quantity of 0.6ℓ or 1.0ℓ may not ensure the proper oil supply to the sliding
part of the compressor when the inclination exceeds 5.6 degrees (9.8%), and may result in
failure to perform normal operation.
*In order to operate the compressor in the state of securing the specified oil quantity, DO
NOT operate two compressors connected in parallel with one system (tandem operation).
The oil quantity may be unbalanced between the two compressors due to a slight difference
in the operating conditions. As a result, it may cause the malfunction of the compressor
when it is used for many years. Accordingly, be sure to use the compressor through
different systems.
Air conditioning unit
Compressor
Train or bus
Figure 1-1. Direction in which the compressor needs to be installed
(2) Oil Quantity Management in the Compressor
* With regard to the oil quantity in the compressor when it is in operation, the oil surface must
be observed with the oil sight glass of the compressor under any of the usage conditions
described in 1-2.(1), and you need to ensure that it is at the minimum oil quantity or more.
* An oil sight glass does not come with the standard compressor. It is possible to provide a
sample compressor with the oil gauge when a customer conducts a product development
test. Please feel free to contact us.
Minimum oil quantity
0.6 liter
1.0 liter
5