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13 Piping installation
NOTICE
The design pressure of the connected air conditioning
parts MUST be 12 MPa (120 bar). If this is not the case,
please contact your dealer for assistance.
CAUTION
When installing a safety valve, ALWAYS add enough
support to the valve. An activated safety valve is under
high pressure. If not installed securely, the safety valve
may cause damage to the piping or the unit.
13.4
Checking the refrigerant piping
Keep the following in mind:
▪ Refrigerant R744 is precharged into the unit.
▪ Always keep both liquid and gas stop valves closed during leak
test and vacuum drying of the field piping.
▪ If installed, see the installation manual of the pressure reduction
kit.
▪ Only use R744 dedicated tools (such as gauge manifold and
charge hose) that are designed to withstand high pressures and
which will prevent water, dirt or dust entering the unit.
CAUTION
Do NOT open the stop valve until you have measured the
insulation resistance of the main power supply circuit.
CAUTION
ALWAYS use nitrogen gas for leak tests.
13.4.1
Checking refrigerant piping: Setup
b
b
a
b
a
b
A
D
B
C
A
Nitrogen (N
)
2
B
R744 refrigerant tank
C
Weighing scales
D
Vacuum pump
E
Outdoor unit
a
Pressure regulator
b
Charge hose
c1, c2
Gas side
d1, d2
Liquid side
e
To refrigeration indoor unit
f
To air conditioning indoor unit
Stop valve
Service port
Field piping
Installation and operation manual
24
E
c1 d1
c2 d2
e
f
NOTICE
The connections to the indoor units and all indoor units
should also be leak and vacuum tested. Keep any possible
(field supplied) field piping valves open as well.
Also see the indoor unit installation manual for more
details. Leak test and vacuum drying should be done
before the power supply is set to the unit.
13.4.2
To perform a leak test
The leak test must satisfy the specifications of EN378‑2.
1 Connect to the gas side (c) and liquid side (d) of the circuit you
want to test. See
"13.4.1 Checking refrigerant piping:
Setup" [ 4 24].
2 Pressurize both liquid side and gas side of the refrigeration
circuit up to 3.0 MPa (30 bar) from the charge port of the stop
valve.
3 Pressurize both liquid side and gas side of the air conditioner
circuit up to 3.0 MPa (30 bar) from the charge port of the stop
valve.
4 Make sure there is no pressure drop for at least 24 hours.
5 If there is a pressure drop, locate the leak and repair.
13.4.3
To perform vacuum drying
1 Connect a vacuum pump to the charge ports of the gas stop
valves (c) and liquid stop valves (d). See
Setup" [ 4 24].
refrigerant piping:
2 Vacuum the unit for at least 2 hours and to –0.1 MPa or below.
3 Leave the unit for more than 1 hour with a vacuum pressure of
–0.1 MPa or less. On the vacuum gauge, check if the pressure
does not increase. If the pressure rises, the system has a leak
or moisture remained into the piping.
In case of a leak
1 Find and repair the leak.
2 When done, vacuum again according to the procedure above.
In case of remaining moisture
When the unit is installed on rainy days, moisture may still remain in
the piping after a first vacuum drying is performed. If so, conduct the
following procedure:
1 Pressurize the nitrogen gas up to 0.05 MPa (for vacuum
destruction) and vacuum for at least 2 hours.
2 Afterwards, vacuum dry the unit to –0.1 MPa or less for at least
1 hour.
3 Repeat vacuum destruction and vacuum drying if the pressure
does not reach –0.1 MPa or less.
4 Leave the unit for more than 1 hour with a vacuum pressure of
–0.1 MPa or less. On the vacuum gauge, check if the pressure
does not increase.
13.5
Insulating the refrigerant piping
After finishing the leak test and vacuum drying, the piping must be
insulated. Take into account the following points:
▪ Be sure to insulate the liquid and gas piping (for all units).
▪ Use heat resistant polyethylene foam which can withstand a
temperature of 70°C for:
▪ all liquid piping at both the air conditioner and the refrigeration
side.
▪ gas piping at the refrigeration side.
▪ Use heat resistant polyethylene foam which can withstand a
temperature of 120°C for gas piping at the air conditioner side.
CO₂ Conveni-Pack outdoor unit and capacity up unit
"13.4.1 Checking
LRYEN10A7Y1+LRNUN5A7Y1
4P605461-1B – 2020.08
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