Johnson Controls SABROE DualPAC, Руководство по эксплуатации

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Operating manual – DualPAC with reciprocating compressors
0012201 en 2021.04
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Design and function
3.2.8 Pressure regulation system (electrical)
The DualPAC unit has two electrical expansion systems. The high-pressure system is connected
to the condenser outlet and regulates the liquid level in the GHUR cooler and controls the expan-
sion between the high and intermediate pressure sides.
The liquid level in the condenser is controlled by the level sensor, pos. 3, Fig. 14 fitted in the re-
ceiver. The sensor registers whether there is refrigerant vapour or liquid in the receiver. At in-
creasing liquid level, the level sensor signals to an electrical regulator in the electrical panel,
which signals the expansion valve, pos. 1, Fig. 15 to open and vice versa.
During normal operation, the receiver should be a little more than half filled with liquid.
In UniSAB III, the set point for the liquid level must be set at 20% in order for the receiver to be a
little more than half filled with liquid. See subsection 8.5 for set-up of the AKS 4100 280 mm level
sensor.
Fig. 15: Pressure regulation
The low level control valve, pos. 2 in Fig. 15 is mounted in the GHUR cooler outlet pipe and regu-
lates the level in the evaporator. It also controls the expansion between the intermediate pressure
and the low pressure side. The level in the evaporator is controlled by the level sensor, pos. 1,
Fig. 16.
Fig. 16: Evaporator level sensor