DC Inverter U-match Series Floor Ceiling Type Unit
16
assembly should be kept closed, otherwise evacuation would fail.
(5). The evacuation duration depends on the unit’s capacity, generally, 20 minutes for the
18K units, 30 minutes for the 24/36K units, 45 minutes for the 48K 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
18/24K units, 10 minutes for the 36/48K units. 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
18K~36K: Refrigerant suitable for a piping length of 5m is charged in the outdoor unit at the
factory. When the piping is longer than 7m, additional charging is necessary.
48K: Refrigerant suitable for a piping length of 7.5m is charged in the outdoor unit at the factory.
When the piping is longer than 10 m, additional charging is necessary.
For the additional amount, see Table 4.4.
Table 4.4
Model
Item
Additional Refrigerant Amount
for Extra Pipe
18K
30 g/m
24~48K
60 g/m
When the height difference between the indoor unit and outdoor unit is larger than 10 meters,
