17
PMML0204 rev.0-05/2010
5. REFRIGERANT PIPING WORK
REFRIGERANT PIPING
WORK
DANGER:
−
Use refrigerant R410A in the refrigerant cycle. Do
not charge oxygen, acetylene or other flammable
and poisonous gases into the refrigerant cycle when
performing a leakage test or an air-tight test. These
types of gases are extremely dangerous and can cause
an explosion. It is recommended that compressed air,
nitrogen or refrigerant be used for these types of tests.
5.1. PIPING mATERIALS
1. Prepare locally-supplied copper pipes.
2. Select clean copper pipes. Make sure there is no dust
and moisture inside. Before connecting pipes, blow the
inside of the pipes with nitrogen or dry air, to remove any
dust or foreign materials.
3. Select the piping size with the correct thickness and
correct material which can have sufficient pressure
strength.
CAUTION
−
Cover the end of the pipe if the pipe has to be inserted
through a hole.
−
Do not put pipes on the ground directly without a cap or
vinyl tape at the end of the pipe.
−
Remove all the flammable materials around the units. If
not, it will cause a fire.
Correct
Incorrect
5.2. CAUTIONS FOR PIPING CONNECTION WORK
a) Connect the indoor/outdoor connecting pipes. Fix the pipes
and pay attention not to contact with weak materials such as
ceiling. (Otherwise, abnormal sound may be heard due to the
vibration of the piping.)
b) Apply refrigerant oil slightly on the sheet surface of the
pipe and flare nut before the flaring work. And then tighten
the flare nut with the specified tightening torque using two
spanners. Perform the flaring work on the liquid piping side
before the gas piping side. Check the gas leakage after the
flaring work.
NOTE:
-Refrigerant oil is field-supplied.
-[Ethereal Oil FVC50K, FVC68D (Idemitsu Kousan Co. Ltd.)]
c) In case that temperature and humidity inside the ceiling
exceed 27ºC/RH80%, apply additional insulation (approx.
10mm thickness) to the accessory insulation. It prevents dew
condensation on the surface of the insulation (refrigerant pipe
only).
d) Perform the air-tight test (4.15MPa for the test pressure).
Refer to Technical Catalog for Outdoor Unit for more details.
e) Perform cold insulation work by insulating and taping the
flare connection and reducer connection. Also insulate all the
refrigerant pipes.
Apply Refrigerant Oil.
Two Spanners Work
- Required Tightening Torque
Pipe Size
Tightening Torque
Ø6.35
(1/4)
14 ~ 18 N-m
Ø9.53
(3/8)
34 ~ 42 N-m
Ø12.7
(1/2)
49 ~ 61 N-m
Ø15.88
(5/8)
68 ~ 82 N-m
Ø19.05
(3/4)
100 ~ 120 N-m
CAUTION
−
Do not apply excessive force to the flare nut when
tightening. If applied, the flare nut may crack due to aged
deterioration and refrigerant leakage may occur. Use the
specified tightening torque.
−
For more details of the refrigerant piping work, vacuum
pumping and refrigerant charge, refer to Technical Catalog
for Outdoor Unit.
