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29 Shut-off Valves and Adaptors
Scroll compressors ZH13KVE and ZH18KVE are delivered with brazing connections. Rotalock type shut-off valves
can also fit compressors with braze connections (by the mean of Rotalock adaptors). Rotalock-shut-off valves are
available for the suction as well as the discharge side (see Figure 18 & spare parts list "ZH").
Torque settings for Rotalock connections:
It is strongly recommended to periodically retorque all pipe and fixing connections to the original setting
after the system has been put into operation.
(1)
pressure control connection
(2)
gauge connection
30 Shell Temperature
Under rare circumstances caused by failure of system components such as the condenser or evaporator fan, or loss
of charge, and depending on the type of expansion control, the top shell and discharge line can briefly but repeatedly
reach temperatures above 177°C as the compressor cycles on its internal protection devices. Care must be taken to
ensure that wiring or other materials, which could be damaged by these temperatures, do not come into contact with
the shell.
31 System Charging Procedure
Rapid charging on only the suction side of a single-phase Scroll equipped system or condensing unit can occasionally
result in a temporary no-start condition for the compressor. The reason for this is that if the flanks of the spirals
happen to be in a sealed position, rapid pressurization of the low side without opposing high side pressure can cause
the spirals to seal axially. As a result, until the pressures eventually equalize, the spirals can be held tightly together,
preventing rotation. The best way to avoid this situation is to charge on both the high and the low side simultaneously
at a rate which does not result in axial loading of the spirals. The maximum charging rate can be determined through
simple tests.
32 Unbrazing System Components
If the refrigerant charge is removed from a scroll-equipped unit by bleeding the high side only, it is sometimes
possible for the scrolls to seal preventing pressure equalization through the compressor. This may leave the low side
shell and suction line tubing pressurized. If a brazing torch is the applied to the low side while the low side shell and
suction line contains pressure, the pressurized refrigerant and oil mixtures could ignite when it escapes and contacts
the brazing flame. To prevent this occurrence, it is important to check both the high and the low side with gauges
before unbrazing, or in the case of repairing a unit on an assembly line, bleed refrigerant from both the low and the
high side. Instructions should be provided in appropriate product literature and assembly (line repair) areas.
C6.2.17/1004/E
Rotalock 1"-12UNF
Rotalock 1"1/4-12UNF
Figure 18. Shut-off valves and adaptors
16
Torque [Nm]
70 – 80
110-135
c
b
Z.8.09.00
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