Daikin RWEYQ72PCYD 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 vacuum
drying.
To prevent entry of any impurities and ensure sufficient pressure resis-
tance, 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

Control box cover

[Caution] label

Pressurize the liquid and gas pipes to
500 microns (do not pressurize more than
500 microns). If the pressure does not drop
within 24 hours, the system passes the test. If the pressure drops,
check where the nitrogen leaks from.

•

Vacuum drying:

Use a vacuum pump which can evacuate to

500 microns.

Evacuate the system from the liquid and gas pipes by using a
vacuum pump for more than 2 hours and bring the system to
500 microns 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 moisture
remaining inside the pipe (if piping work is carried out during 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
7.25 psig (0.05 MPa) (vacuum break) with nitrogen gas and evac-
uate the system again using the vacuum pump for 1 hour to
500 microns or less (vacuum drying). If the system cannot be
evacuated to 500 microns 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.

NOTE

Make sure to perform air tight test and vacuum drying using the service
ports of the stop valve shown in the table below.

9-7 Pipe insulation

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

• Make sure to insulate the connection piping and refrigerant branch

kits entirely.

• Be sure to insulate the liquid-side, suction gas-side and discharge

gas-side piping for the inter-unit piping and the refrigerant branch kits.
Not insulating them may cause leaking. (The gas piping can reach
temperatures of 250°F (120°C). Be sure the insulation used can
withstand such temperatures.)

• If you think the humidity around the cooling piping might exceed

86°F (30°C) and RH80%, reinforce the insulation on the cooling pip-
ing (at least 13/16 in. (20 mm) thick). Condensation might form on
the surface of the insulation.

• If there is a possibility that condensation on the stop 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.

WARNING

• 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 supply 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 supply circuit is not
deteriorated.
Using a megatester for 500 V, check that the insulation resistance of
2 M

Ω

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

power supply and ground terminals. Never use the megatester for
the transmission wiring (between outside and indoor unit, outside
and Cool/Heat selector and etc.).

9-9 Additional refrigerant charge

WARNING

• To avoid injury always use protective gloves and eye protection

when charging refrigerant.

•

To avoid injury do not charge with unsuitable substances. Use only
the appropriate refrigerant.

NOTE

•

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 (see above).
When charging a system, care shall be taken that its maximum per-
missible charge is never exceeded, in view of the danger of liquid
hammer.
Refrigerant containers shall be opened slowly.

TO AVOID COMPRESSOR BREAKDOWN. DO NOT CHARGE THE
REFRIGERANT MORE THAN THE SPECIFIED AMOUNT TO RAISE
THE CONDENSING PRESSURE.

• This outside unit is factory charged with refrigerant and depending

on pipe sizes and pipe lengths some systems require additional
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 materi-
als from mixing into the system.

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

How to charge with the siphon tank.

Other ways of charging with the tank.

One outside unit installed

Liquid pipe stop valve
Discharge gas pipe stop valve
Suction gas pipe stop valve

Multiple outside units installed

Liquid pipe stop valve
Discharge gas pipe stop valve
Suction gas pipe stop valve
Oil-equalizing pipe stop valve