– 12 –
Outdoor Unit
Installation Manual
6
Air purging
■
Airtight test
After completing the refrigerant piping work, perform an airtight test. Connect a nitrogen gas cylinder and
pressurize the pipes with nitrogen gas as follows to conduct the airtight test.
Gas leak check
Step 1....Pressurize to
0.5 MPa
(5 kg/cm
2
G) for 5 minutes or longer.
Step 2....Pressurize to
1.5 MPa
(15 kg/cm
2
G) for 5 minutes or longer.
Step 3....Pressurize to
4.15 MPa
(42 kg/cm
2
G) <HWT-40, 60 model> for 24 hours.
Pressurize to
4.6 MPa
(46 kg/cm
2
G) <HWT-80, 110 model> for 24 hours.
(However, note that when the ambient temperature differs during pressurization and after 24 hours, the pressure
will change by approximately 0.01 MPa (0.1 kg/cm
2
G) per 1°C, so this should be compensated.)
* After the airtight test is completed, evacuate the nitrogen gas.
If the pressure drops in steps 1 through 3, check the connections for leakage.
Check for leaks with foaming liquid, etc., take steps to fix the leaks such as brazing the pipes again and tightening
the flare nuts, and then perform the airtight test again.
V
L
V
H
High pressure gauge
Gauge manifold
Low pressure gauge
Nitrogen gas
Charge port
Pressure reducing
valve
CAUTION
Never use oxygen, flammable gas, or noxious
gas for the airtight test.
Major leaks can be discovered.
Micro leaks can be
discovered.
■
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 to Water Heat Pump when the
pump stops.
(If oil in the vacuum pump is put in an Air to Water Heat
Pump including R32, it may cause trouble with the
refrigeration cycle.)
Pressure gauge
Gauge manifold valve
Handle High
(Keep fully closed)
Compound pressure gauge
Charge hose
(For R32 or R410A only)
Vacuum pump
adapter for backflow
prevention
(For R32 or R410A
only)
–101 kPa
(–76 cmHg)
Handle Low
Charge hose
(For R32 or
R410A only)
Charge port
(Valve core
(Setting pin))
Packed valve at gas side
Vacuum
pump
23-EN
24-EN
Содержание HWT-1101HRW-E
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