DC Inverter Cassette Type Unit
16
(5). The evacuation duration depends on the unit’s capacity, generally,
20 minutes for the 18K
units, 30 minutes for the 24/36K units,
and verify if the pressure gauge at the low pressure
side of the manifold valve assembly reads -1.0Mp (-75cmHg), if not, it indicates there is leak
somewhere. Then, close the switch fully and then stop the vacuum pump.
(6). Wait for some time to see if the system pressure can remain unchanged,
5 minutes for the
18K~24K units, 10 minutes for the units
36
K. During this time, the reading of the pressure
gauge at the low pressure side can not be larger than 0.005Mp (0.38cmHg).
(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
pipe
pipe
VAC valve
Vacuum pump
Service port
Low pressure gauge
High pressure gauge
Gauge manifold kit
Fig.20
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.
4.4.2 Additional Charge
Refrigerant suitable for a piping length of 5m is charged in the
18
~
42
K outdoor unit at the
factory.
When the piping of
18
~
42
k unit is longer than 7.5m
,
additional charging is necessary.
For the additional amount, see Table 10.
Table 10
Model
Item
Standard Pipe Length
Unnecessary Charge
Pipe Length
Additional Refrigerant Amount
for Extra Pipe
18K
5m
≤ 7.5m
30 g/m
24~
42
K
5m
≤ 7.5m
60 g/m
