11
4) Turn on the Nitrogen bottle valve, ensuring that air outlet pressure at the pressure reducing valve increases to
0.5Mpa(5kg/cm
2
g), and then turn on the valve which connects the gas side Pipes to and the instrument distributor.
Air intake
Air offtake
0.5MPa
(5kg/cm
2
G)
Pressure
reducing
valve
valve
Nitrogen
Preesure
0.5MPa
(5kg/cm
2
G)
copper pipe
6.4
copper pipe
6.4
VL VH
Indoor
Outdoor
High air
pressure mete
Low air pressure meter
3-way valve fully closed
(Gas side)
Instrument shunt
Fully tightened
Fully tightened
Fully tightened
3-way valve fully closed
(Liquid side)
Braze welding joint
Braze welding joint
Braze welding joint
Service port
Service port
Relief valve
Nitrogen tanker
Outdoor units
Indoor units
Air tightness test
Air tightness test should be carried out after refrigerant piping completes.
Air tightness test uses nitrogen tanker to pressurize as shown below.
Valves of both gas and liquid should be closed off. In order to prevent nitrogen into recycle system of outdoor unit,
make sure valve handle is tightened. (Both sides of gas and liquid)
Pressurize to each refrigeration system should be slow step by step.Pressurization must be executed through gas
and liquid valve.
Notice
It is absolutely forbidden to use oxygen, inflammable gas or harmful gas to do air tightness test.
Step 1: 0.3MPa(3.0kg/cm
2
g) Pressurize more than three minutes.
Step 2: 1.5MPa(15kg/cm
2
g) Pressurize more than three minutes.----- Find out serious leakage.
Step 3: 3.0MPa(30kg/cm
2
g) Pressurize about 24 hours.----- Find out slight leakage.
Installation Procedures
Connecting piping
5) Block up at the end of an indoor unit gas pipe by hand. When the pressure inside the gas pipe is at the required
pressure for cleaning, remove the hand swiftly to allow the air to escape from inside the pipe. Then repeat the
process until the pipe is clean. (Place a piece of gauze at the end of the pipe to confirm that all foreign articles and
water have been removed.Cleaning can cease when no foreign bodies are wisible on the gauze.)
6) Turn off the instrument distributor and repeat the operation cycle for the next indoor unit.When all gas pipes are
finished,turn off the instrument distributor,and then turn on the valve which connects lipuid pipes to the instrument
distributor to clean the liquid pipes using the same method as for the gas pipes.
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