Daikin VRV-WIII Installation Manual Download

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9-6 Air tight test and vacuum drying

The units were checked for leaks by the manufacturer.
Confirm that the valves are firmly closed before Air tight test or vac-
uum drying.
To prevent entry of any impurities and insure sufficient pressure
resistance, always use the special tools dedicated for R410A.

•

Air tight test:

Make sure to use nitrogen gas.

(For the service port location, refer to the
“Caution” label attached on the front panel
[right] of the outside unit.)

(Refer to figure)

[Service precautions] Label

EL. COMPO. BOX cover

[Caution] Label

Pressurize the liquid and gas pipes to
4.0MPa (40bar) (do not pressurize more
than 4.0MPa (40bar)). If the pressure does
not drop within 24 hours, the system passes the test. If the pres-
sure drops, check where the nitrogen leaks from.

•

Vacuum drying:

Use a vacuum pump which can evacuate to

–100.7kPa (5Torr, –755mmHg).

Evacuate the system from the liquid and gas pipes by using a
vacuum pump for more than 2 hours and bring the system to
–100.7kPa or less. After keeping the system under that condi-
tion for more than 1 hour, check if the vacuum gauge rises or
not. If it rises, the system may either contain moisture inside or
have leaks.

Following should be executed if there is a possibility of mois-
ture remaining inside the pipe (if piping work is carried out dur-
ing the raining season or over a long period of time rainwater
may enter the pipe during work).
After evacuating the system for 2 hours, pressurize the system
to 0.05MPa (vacuum break) with nitrogen gas and evacuate
the system again using the vacuum pump for 1 hour to
–100.7kPa or less (vacuum drying). If the system cannot be
evacuated to –100.7kPa within 2 hours, repeat the operation of
vacuum break and vacuum drying.
Then, after leaving the system in vacuum for 1 hour, confirm
that the vacuum gauge does not rise.

9-7 Pipe insulation

After finishing the leak test and vacuum drying, the piping must be
insulated. Take into account the following points:

• Make sure to insulate the connection piping both liquid-side and

gas-side and refrigerant branch kits entirely.
Not insulating them may cause leaking. (The gas piping can reach
temperatures of 120°C. Be sure the insulation used can withstand
such temperatures.)

• Reinforce the insulation on the refrigerant piping according to the

installation environment. Condensation might form on the surface
of the insulation.

• If there is a possibility that condensation on the shutoff valve might

drip down into the indoor unit through gaps in the insulation and
piping because the outside unit is located higher than the indoor
unit, etc., this must be prevented by caulking the connections, etc.

Caution

Be sure to insulate connection piping, as touching them can
cause burns.

9-8 Checking of device and installation conditions

Be sure to check the followings.

Make sure there is no faulty power wiring or loosing of a nut.
See “

8. FIELD WIRING

”.

Make sure there is no faulty transmission wiring or loosing of a nut.
See “

8. FIELD WIRING

”.

Make sure there is no faulty refrigerant piping.
See “

9.REFRIGERANT PIPING

”.

Make sure piping size is correct.
See “

9-1 Selection of piping material

”.

Make sure insulation work is done.
See “

9-7 Pipe insulation

”.

Make sure insulation resistance of main power circuit is not dete-
riorated.
Using a megatester for 500V, check that the insulation resistance
of 2M

Ω

or more is attained by applying a voltage of 500V DC

between power terminals and earth. Never use the megatester for
the transmission wiring (between outdoor and indoor unit, outdoor
and COOL/HEAT selector and etc.).

9-9 Additional refrigerant charge

Caution

• Refrigerant cannot be charged until field wiring has been com-

pleted.

• Refrigerant may only be charged after performing the leak test

and the vacuum drying.

• When charging a system, care shall be taken that its maximum

permissible charge is never exceeded, in view of the danger of liq-
uid hammer.

• Charging with an unsuitable substance may cause explosions

and accidents, so always ensure that the appropriate refrigerant
(R410A) is charged.

• Refrigerant containers shall be opened slowly.
• Always use protective gloves and protect your eyes when charg-

ing refrigerant.

• This outside unit is factory charged with refrigerant and depend-

ing on pipe sizes and pipe lengths some systems require addi-
tional charging of refrigerant.

• Determine the amount of refrigerant to be added by referring to the

table, write it down on the included “Added Refrigerant” plate and
attach it to the rear side of the front cover.
Note: refer to the example of connection for the amount to be added.

Additional refrigerant charge procedure (1)-normally

• Charge the refrigerant to the liquid pipe in its liquid state. Since

R410A is a mixed refrigerant, its composition changes if charged
in a state of gas and normal system operation would no longer be
assured.

• Make sure to use installation tools you exclusively use on R410A

installations to withstand the pressure and to prevent foreign
materials from mixing into the system.

Before charging, check whether the tank has a siphon attached or
not.

How to charge with a siphon attached tank.

How to charge with other tank.

After the vacuum drying is finished, charge the additional refriger-
ant in its liquid state through the liquid shutoff valve service port.
Taking into account following instructions:

•

Check that gas and liquid shutoff valves are closed.

•

Stop the compressor and charge the specified weight of refrig-
erant.

(If the outside unit is not in operation and the total amount cannot
be charged, follow the Additional refrigerant charge procedure (2)
shown below.)

Note

•

Procedures for charging additional refrigerant.

(Refer to figure 24)

Pressure reducing valve

Nitrogen

Refrigerant tank