Mitsubishi Electric PUHY-RP200YJM-A [17/34] Airtight test evacuation and refriger ant charging

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Caution:

Only use refrigerant R410A.

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

will deteriorate the refrigerating machine oil or cause the compressor to malfunc-

tion.

2 Evacuation

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

nection 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.

(If the degree of vacuum increase is larger than 130 Pa, water might have

entered. Apply pressure to dry nitrogen gas up 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.

[Fig. 10.3.2] (P.7)

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

Note:

•Always add an appropriate amount of refrigerant. Also always charge

the system with liquid refrigerant.

• Use a gauge manifold, charging hose, and other parts for the refrigerant

indicated on the unit.

• Use a graviometer. (One that can measure down to 0.1 kg.)

• Use a vacuum pump with a reverse flow check valve.

(Recommended vacuum gauge: ROBINAIR 14830A Thermistor Vacuum

Gauge)

Also use a vacuum gauge that reaches 65 Pa [abs] or below after operat-

ing for five minutes.

• 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.)

Caution:

• Keep the valve closed until refrigerant charging to the pipes to be added

on site has been completed. Opening the valve before charging the

refrigerant may cause damage to the unit.

• Do not use a leak detection additive.

[Fig. 10.2.3] (P.6)

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.

Heat

insulation

material A

Outer

covering B

3 Refrigerant Charging

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 refriger-

ant 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 refriger-

ant 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 re-

frigerant remaining in the cylinder.

[Fig. 10.3.3] (P.7)

A Syphon pipe B

In case of the R410A cylinder having no syphon pipe.

10.4. Thermal insulation of refrigerant piping

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.

[Fig. 10.4.1] (P.7)

A Steel wire B Piping

C Asphaltic oily mastic or asphalt D Heat insulation material A

E Outer covering B

Glass fiber + Steel wire

Adhesive + Heat - resistant polyethylene foam + Adhesive tape

Indoor Vinyl tape

Floor exposed Water-proof hemp cloth + Bronze asphalt

Outdoor Water-proof hemp cloth + Zinc plate + Oily paint

Note:

• When using polyethylene cover as covering material, asphalt roofing shall

not be required.

• No heat insulation must be provided for electric wires.

[Fig. 10.4.2] (P.7)

A Liquid pipe B Gas pipe C Electric wire

D Finishing tape E Insulator

[Fig. 10.4.3] (P.7)

Service port

(N·m)

Outer diameter of

copper pipe (mm)

ø9.52

ø12.7

ø15.88

ø19.05

ø25.4

Cap (N·m)

Shaft (N·m)

Size of hexagonal

wrench (mm)

Appropriate tightening torque:

Caution:

Make sure to seal-off the openings for the pipe and wire retrieval.

• Small animals, rainwater, or snow entering through the openings may

cause damage to the device.

10.3. Airtight test, evacuation, and refriger-

ant charging

1 Airtight test

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

tion 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.7)

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 refriger-

ant (R410A), gas leakage causes the composition to change and affects perform-

ance. Therefore, perform the airtightness test cautiously.

Restriction

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

gas, it may catch fire or explode.

Airtight test procedure

(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 (Kyuboflex, etc.) and visually check for bubbles.

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

WT05910X01_en_e.p65 10.5.18, 15:4517

Mitsubishi Electric PUHY-RP200YJM-A [17/34] Airtight test evacuation and refriger ant charging

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