Mitsubishi Electric PUHZ-FRP71VHA2 Installation Manual page 7

4. Installing the refrigerant piping
Stop valve
A
B
C
D
E
A Service port D Sealed, same way for gas side
B Open/Close section E Pipe cover
C Local pipe
Fig. 4-4
(2)
Fig. 4-5
A Valve H Double spanner section
B Unit side (Do not apply a spanner other than to this
C Cap section. Doing so would cause coolant leaks.)
D Local pipe side I Seal section
E Pipe cover (Seal the end of the heat insulation material at
F Service port the pipe connection section with whatever seal
G Wrench hole material you have on hand so that water does
not infiltrate the heat insulation material.)
B
C
Fig. 4-6
4.6. Addition of refrigerant
• Additional charging is not necessary if the total pipe length does not exceed 30 m.
• If the total pipe length exceeds 30m, charge the unit with additional R410A re-
frigerant according to the permitted pipe lengths in the chart shown on the right.
* 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.
* The figure to the left is an example
only.
A
The stop valve shape, service port
position, etc., may vary according to
the model.
* Turn section only.
A
(Do not further tighten sections A
D
and together.)
B
Charge hose
C
Service port
D
4.4. Refrigerant pipe airtight testing method (Fig. 4-4)
(1) Connect the testing tools.
• Make sure the stop valves are closed and do not open them.
• Add pressure to the refrigerant lines through the service port A of the liquid
stop valve.
(2) Do not add pressure to the specified pressure all at once; add pressure little by
little.
1 Pressurize to 0.5 MPa (5 kgf/cm
pressure does not decrease.
2 Pressurize to 1.5 MPa (15 kgf/cm
pressure does not decrease.
3 Pressurize to 4.15 MPa (41.5 kgf/cm
perature and refrigerant pressure.
(3) If the specified pressure holds for about one day and does not decrease, the
pipes have passed the test and there are no leaks.
• If the surrounding temperature changes by 1 °C, the pressure will change by
about 0.01 MPa (0.1 kgf/cm G). Make the necessary corrections.

(4) If the pressure decreases in steps (2) or (3), there is a gas leak. Look for the
source of the gas leak.
4.5. Stop valve opening method (Fig. 4-5)
The stop valve opening method varies according to the outdoor unit model. Use the
appropriate method to open the stop valves.
1 Remove the cap and turn the valve rod counterclockwise as far as it will go with
the use of a 4 mm hexagonal wrench. Stop turning when it hits the stopper.
(ø9.52: Approximately 10 revolutions)
2 Make sure that the stop valve is open completely, push in the handle and rotate
the cap back to its original position.
Refrigerant pipes are protectively wrapped
• The pipes can be protectively wrapped up to a diameter of ø90 before or after
connecting the pipes. Cut out the knockout in the pipe cover following the groove
and wrap the pipes.
Pipe inlet gap
• Use putty or sealant to seal the pipe inlet around the pipes so that no gaps re-
main. (If the gaps are not closed, noise may be emitted or water and dust will
enter the unit and breakdown may result.)
Precautions when using the charge valve (Fig. 4-6)
Do not tighten the service port too much when installing it, otherwise, the valve
core could be deformed and become loose, causing a gas leak.
After positioning section B in the desired direction, turn section A only and tighten
it.
Do not further tighten sections A and B together after tightening section A.
• 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
performance.
Permitted pipe Permitted vertical
length (total) difference
-60 m -20 m
* The total pipe length equals the indoor-outdoor pipe length plus the
cylinder- or hydrobox-outdoor pipe length. The max. pipe length for
each side is 30 m.
G), wait five minutes, and make sure the

G), wait five minutes, and make sure the

G) and measure the surrounding tem-

Additional refrigerant charging amount
(total)
31 - 40 m 41 - 50 m 51-60
0.6 kg 1.2 kg 1.8 kg
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