Johnson Controls DHR18CSB21S, Installation And Maintenance Manual

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(7) Slightly open the liquid valve and let some refrigerant go to the connection pipe to balance the
pressure inside and outside of the connection pipe, so that air will not come into the connection
pipe when removing the hose. Note that the gas and liquid valve can be opened fully only after the
manifold valve assembly is removed.
(8) Place back the caps of the liquid valve, gas valve and also the service port.
Hose with the valve pin
gauge manifold Pressure gauge (Low-pressure)
Pressure gauge (Hi-pressure)
Switch (Low-pressure)
Switch (Hi-pressure)
Connection pipe (to indoor unit)
Liquid valve
Gas valve
Service port
Cap
Hose
Vacuum pump
Cap
Service pipe
Cap
Connection pipe
Figure 3-3-7
Note:
For the large-sized unit, it has the service port for both the gas valve and the liquid valve.
During evacuation, it is available to connect two hoses of the manifold valve assembly to two service ports
to quicken the evacuating speed.
4
.1.7.2 Additional Charge
Refrigerant suitable for a piping length of 7.6m (25feet) is charged in the outdoor unit at the factory.
When the piping is longer than 7.6m (25feet), additional charging is necessary.
For the additional amount, see Table 3-3-2.
Table 3-3-2
Item
Model
Additional Refrigerant Amount for
Extra Pipe
18k 45g per 1.5 m (1.6 ounce per 5 feet )
24k~48k 90g per 1.5 m (3.2 ounce per 5 feet )
When the height difference between the indoor unit and outdoor unit is larger than 10m (32-4/5feet),