3.2 CH unit
3.2.1 Considerations
D A N G E R
•
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.
3.2.2 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.
C A U T I O N
•
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.
3.2.3 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.
1
Apply refrigerant oil.
2
Two spanners work.
N O T E
•
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. 10
mm thickness) to the accessory insulation. It prevents dew condensation on the surface of the insulation (refrigerant pipe
only).
D) Perform the air-tight test (4.15 MPa 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.
1
2
3 Piping work and
refrigerant charge
66
SMGB0065 rev. 1 - 12/2010
