Mitsubishi Electric 250 YHA-A, Installation Manual

9

B

G

H

C

A

F

E

D

I

Fig. 5-6

1

2

5. Installing the refrigerant piping

5.5. Stop valve opening method (Fig. 5-6)

(1) Remove the cap and turn the valve rod counterclockwise as far as it will go with

the use of hexagonal wrench. Stop turning when it hits the stopper.

(2) Make sure that the stop valve is open completely, push in the handle and rotate

the cap back to its original position.

A

Valve

B

Unit side

C

Open

D

Cap

E

Local pipe side

5.6. Addition of refrigerant (Fig. 5-7)

• Additional charging is not necessary for this unit if the pipe length does not exceed

30 m.

• If the pipe length exceeds 30 m, charge the unit with additional R410A refrigerant

according to the permitted pipe lengths in the chart below.

* When the unit is stopped, charge the unit with the additional refrigerant through

the liquid stop valve after the pipe extensions and indoor unit have been
vacuumized.
When the unit is operating, add refrigerant to the gas check valve using a
safety charger. Do not add liquid refrigerant directly to the check valve.

* After charging the unit with refrigerant, note the added refrigerant amount on

the service label (attached to the unit).
Refer to the “1.5. Using R410A refrigerant air conditioners” for more informa-

tion.

• Be careful when installing multiple units. Connecting to an incorrect indoor unit can

lead to abnormally high pressure and have a serious effect on operation perform-
ance.

A+B+C+D

Amount of additional refrigerant charge (kg)

30 m and less

31-40 m and less

41-50 m and less

51-60 m and less

61-70 m and less

71-120 m and less

0.9 kg

1.8 kg

2.7 kg

3.6 kg

1.2 kg

2.4 kg

3.6 kg

4.8 kg

Outdoor unit

RP200

RP250

At time of shipping

(kg)

10.5

10.5

No additional

charge necessary

Calculate the amount of

additional refrigerant

charge using formula

provided below.

Main piping:
Liquid line size
ø9.52 overall length 

×

0.09 (Gas line: ø28.58)

(m) 

×

 0.09 (kg/m)

Branch piping: Liquid
line size
ø9.52 overall length 

×

0.06 (Gas line: ø15.88)

(m) 

×

 0.06 (kg/m)

Branch piping: Liquid
line size
ø6.35 overall length 

×

0.02 (Gas line: ø15.88)

(m) 

×

 0.02 (kg/m)

3.6 (kg)

Amount of additional
charge

(kg)

Main piping:
Liquid line size
ø12.7 overall length 

×

0.12

(m) 

×

 0.12 (kg/m)

+

+

+

–

=

Additional charge amount
for 70 meters

RP200 3.6 kg
RP250 4.8 kg

When length exceeds 70 m

When the total length of the piping exceeds 70 m, calculate the amount of additional charge based on the following requirements.

Note: If the calculation produces a negative number (i.e. a “minus” charge), of if calculation results in an amount that is less than the “Additional charge amount for 70 m,”

perform the additional charge using the amount shown in “Additional charge amount for 70 m.”

Fig. 5-7

1

Indoor unit

2

Outdoor unit

3

Main piping

4

Branch piping

5

Multi distribution
pipe (option)

Outdoor unit : RP250 A: ø12.7 ... 65 m
Indoor unit 1 : RP71

B: ø9.52 ... 5 m

Indoor unit 2 : RP71

C: ø9.52 ... 5 m

Indoor unit 3 : RP71

D: ø9.52 ... 5 m

Main piping ø12.7 is A = 65 m
Branch piping ø9.52 is B + C + D = 15 m
Therefore, the amount of additional charge is: 65 

×

 0.12 + 15 

×

 0.06 -3.6=5.1 (kg)

(Fractions are rounded up)

F

Close

G

Service port

H

Wrench hole

Liquid side : 4 mm hexagonal wrench

Gas side :

10 mm hexagonal wrench

D

A

H

B

C

1

1

1

4

4

4

5

3

2

Max. 1m