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Digital Inverter
Installation Manual
8
CAUTION
1.
Do not put the crescent wrench on the cap or cover.
The valve may break.
2.
If applying excessive torque, the nut may break
according to some installation conditions.
• After the installation work, be sure to check for gas
leaks of the pipe connections with nitrogen.
• Pressure of R410A is higher than that of R22 (Approx.
1.6 times).
Therefore, using a torque wrench, tighten the flare
pipe connecting sections that connect the indoor/
outdoor units at the specified tightening torque.
Incomplete connections may cause not only a gas
leak, but also trouble with the refrigeration cycle.
Refrigerant Pipe Length
Single
NO GOOD
Cover
Cap
Do not apply refrigerant oil to the flared surface.
Outdoor
unit
Allowable pipe length (m)
Height difference (m)
Total length
Indoor-outdoor H
Minimum
Maximum
Indoor unit: Upper
Outdoor unit: Upper
SM2244
7.5
70
30
30
SM2804
7.5
70
30
30
Outdoor
unit
Pipe diameter (mm)
Number of bent portions
Gas side
Liquid side
SM2244
Ø28.6
Ø12.7
10 or less
SM2804
Ø28.6
Ø12.7
10 or less
H
Indoor Unit
Outdoor Unit
Figure of Single
6
AIR PURGING
Airtight Test
Before starting an airtight test, further tighten the spindle
valves on the gas side and liquid side.
Pressurize the pipe with nitrogen gas charged from the
service port to the design pressure (4.15 MPa) to
conduct the airtight test.
After the airtight test is completed, evacuate the nitrogen
gas.
Air Purge
With respect to the preservation of the terrestrial
environment, adopt “Vacuum pump” to purge air
(Evacuate air in the connecting pipes) when installing the
unit.
• Do not discharge the refrigerant gas to the
atmosphere to preserve the terrestrial environment.
• Use a vacuum pump to discharge the air (nitrogen,
etc.) that remains in the set. If air remains, the capacity
may decrease.
For the vacuum pump, be sure to use one with a
backflow preventer so that the oil in the pump does not
backflow into the pipe of the air conditioner when the
pump stops.
(If oil in the vacuum pump is put in an air conditioner
including R410A, it may cause trouble with the
refrigeration cycle.)
Vacuum pump
Pressure gauge
Gauge manifold valve
Handle High
(Keep fully closed)
Compound pressure gauge
Charge hose
(For R410A only)
Vacuum pump
adapter for counter-
flow prevention
(For R410A only)
–101 kPa
(–76 cmHg)
Handle Low
Charge hose
(For R410A only)
Charge port
(Valve core
(Setting pin))
Packed valve at gas side
Vacuum
pump
As shown in the figure, connect the charge hose after
the manifold valve is closed completely.
L
Attach the connecting port of the charge hose with a
projection to push the valve core (setting pin) to the
charge port of the set.
L
Open Handle Low fully.
L
Turn ON the vacuum pump. (*1)
L
Loosen the flare nut of the packed valve (Gas side) a
little to check that the air passes through. (*2)
L
Retighten the flare nut.
L
Execute vacuuming until the compound pressure
gauge indicates –101 kPa (–76 cmHg). (*1)
L
Close Handle Low completely.
L
Turn OFF the vacuum pump.
L
Leave the vacuum pump as it is for 1 or 2 minutes, and
check that the indicator of the compound pressure
gauge does not return.
L
Open the valve stem or valve handle fully. (First, at
liquid side, then gas side)
L
Disconnect the charge hose from the charge port.
L
Tighten the valve and caps of the charge port securely.
EN-15
EN-16
