Справочник Пользователя для Mitsubishi Electronics puhy-ep-yjm-a(-bs)

GB

A

  Example of closure materials (field supply)

B

  Fill the gap at the site

Make sure to seal-off the space around areas where the wires and refrigerant 

pipes enter the unit to ensure that small animals, rainwater, or snow cannot 

enter the unit through such openings and cause damage to the unit.

1

 

 

Perform with the valve of the outdoor unit closed, and pressurize the 

connection piping and the indoor unit from the service port provided on the 

valve of the outdoor unit. (Always pressurize from both the liquid pipe and 

the gas pipe service ports.)
[Fig. 10.3.1] (P.8)

A

Nitrogen gas

B

To indoor unit

C

System analyzer

D

Low knob

E

Hi knob

F

Valve

G

Liquid pipe

H

Gas pipe

I

Outdoor unit

J

Service port

Observe the following restrictions when conducting an air tightness test 

to prevent negative effects on the refrigerating machine oil. Also, with 

nonazeotropic refrigerant (R410A), gas leakage causes the composition to 

change and affects performance. Therefore, perform the airtightness test 

cautiously.

-  The use of other refrigerants such as R22 or R407C, which contains chlorine, 

will deteriorate the refrigerating machine oil or cause the compressor to 

malfunction.

2

 

 

Evacuate with the valve of the outdoor unit closed and evacuate both the 

connection piping and the indoor unit from the service port provided on the 

valve of the outdoor unit using a vacuum pump. (Always evacuate from the 

service port of both liquid pipe and gas pipe.) After the vacuum reaches  

650 Pa [abs], continue evacuation for at least one hour or more. Then, stop 

the vacuum pump and leave it for 1 hour. Ensure the degree of vacuum 

has not increased. 

to 0.05 MPa and vacuum again.) Finally, seal in with the liquid refrigerant 

through the liquid pipe, and adjust the gas piping to obtain an appropriate 

amount of the refrigerant during operation.

 

* Never perform air purging using refrigerant.

A

System analyzer

B

Low knob

C

Hi knob

D

Valve

E

Liquid pipe

F

Gas pipe

G

Service port

H

Three-way joint

I

Valve

J

Valve

K

R410A cylinder

L

Scale

M

Vacuum pump

N

To indoor unit

O

Outdoor unit

3

 

 

Since the refrigerant used with the unit is nonazerotropic, it must be charged 

in the liquid state. Consequently, when charging the unit with refrigerant from 

a cylinder, if the cylinder does not have a syphon pipe, charge the liquid 

refrigerant by turning the cylinder upside-down as shown in Fig.10.3.3. If 

the cylinder has a syphon pipe like that shown in the picture on the right, 

the liquid refrigerant can be charged with the cylinder standing upright. 

Therefore, give careful attention to the cylinder specifications. If the unit 

should be charged with gas refrigerant, replace all the refrigerant with new 

refrigerant. Do not use the refrigerant remaining in the cylinder.
[Fig. 10.3.3] (P.8)

A

Syphon pipe

B

In case of the R410A cylinder having  no syphon pipe.

Airtight test procedure

Restriction

(1) After pressurizing to the design pressure (4.15 MPa) using nitrogen gas, allow it to stand 

for about one day. If the pressure does not drop, airtightness is good.
However, if the pressure drops, since the leaking point is unknown, the following bubble 
test may also be performed.

(2) After the pressurization described above, spray the flare connection parts, brazed parts, and 

other parts that may leak with a bubbling agent (Gupoflex, etc.) and visually check for bubbles.

(3) After the airtight test, wipe off the bubbling agent.

If a flammable gas or air (oxygen) is used as the pressurization 

• 

gas, it may catch fire or explode.

Determine the amount of additional refrigerant charge by using the formula, 

• 

and charge refrigerant additionally through the service port after completing 

piping connection work.
After completing work, tighten the service port and cap securely so as not to 

• 

generate any gas leakage.  (Refer to the table on the below for appropriate 

tightening torque.)

Appropriate tightening torque:

Outer diameter 

of copper pipe 

(mm)

Cap 

(N·m)

Shaft 

(N·m)

Size of 

hexagonal 

wrench (mm)

Service port 

(N·m)

ø9.52

15

6

4

12

ø12.7

20

9

4

ø15.88

25

15

6

ø19.05

25

30

8

ø25.4

25

30

8

ø28.58

25

-

-

16

Be sure to add insulation work to refrigerant piping by covering liquid pipe and 

gas pipe separately with enough thickness heat-resistant polyethylene, so that 

no gap is observed in the joint between indoor unit and insulating material, and 

insulating materials themselves. When insulation work is insufficient, there is a 

possibility of condensation drip, etc. Pay special attention to insulation work in 

the ceiling plenum.

A

Steel wire

B

Piping

C

Asphaltic oily mastic or asphalt

D

Heat insulation material A

E

Outer covering B

Heat 

insulation 

material A

Glass fiber + Steel wire
Adhesive + Heat - resistant polyethylene foam + Adhesive tape

Outer 

covering B

Indoor

Vinyl tape

Floor exposed Water-proof hemp cloth + Bronze asphalt

Outdoor

Water-proof hemp cloth + Zinc plate + Oily paint

A

Liquid pipe

B

Gas pipe

C

Electric wire

D

Finishing tape

E

Insulator

WT05962X01_GB.indd   18

2010/08/26   19:20:59