Specifications

ManualsBrandsDaikin ManualsAir ConditionerRXYQQ20T7Y1B

RXYQQ8~20T7Y1B

VRV IV System Air Conditioner

4P345099-1 – 2013.04

Installation and operation manual

10.4.6. Vacuum drying

To remove all moisture from the system, proceed as follows:

1 Evacuate the system for at least 2 hours to a target vacuum of

–100.7 kPa.

2 Check that, with the vacuum pump turned off, the target vacuum

is maintained for at least 1 hour.

3 Should you fail to reach the target vacuum within 2 hours or

maintain the vacuum for 1 hour, the system may contain too

much moisture.

4 In that case, break the vacuum by pressurizing with nitrogen gas

to a gauge pressure of 0.05 MPa (0.5 bar) and repeat steps 1 to

3 until all moisture has been removed.

5 The outdoor stop valves can now be opened, and/or additional

refrigerant can be charged (see "14.4. Method for adding

refrigerant" on page 32).

11. 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 and refrigerant

branch kits entirely.

 Be sure to insulate the liquid and gas piping (for all units).

 Use heat resistant polyethylene foam which can withstand a

temperature of 70°C for liquid piping and polyethylene foam

which can withstand a temperature of 120°C for gas piping.

 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 stop valve might

drip down into the indoor unit through gaps in the insulation and

piping because the outdoor unit is located higher than the indoor

unit, this must be prevented by sealing up the connections. See

below figure.

1 Insulation material

2 Caulking etc.

12. Electrical wiring work

12.1. Precautions on electrical wiring work

For the existing power supply and transmission wiring, check that the

specifications match the requirements as described in this chapter

and that other parts (especially terminals) do not appear to have

deteriorated. Implement appropriate procedures (e.g., replacement) if

required.

NOTICE

Make sure to use a recommended bubble test solution

from your wholesaler. Do not use soap water, which may

cause cracking of flare nuts (soap water may contain salt,

which absorbs moisture that will freeze when the piping

gets cold), and/or lead to corrosion of flared joints (soap

water may contain ammonia which causes a corrosive

effect between the brass flare nut and the copper flare.

INFORMATION

After opening the stop valve, it is possible that the pressure

in the refrigerant piping does not rise. This might be

caused by e.g., the closed state of the expansion valve in

the outdoor unit circuit, but does not present any problem

for correct operation of the unit.

NOTICE

The connections to the indoor units and all indoor units

should also be leak and vacuum tested. Keep, if existing,

all (field supplied) field valves to the indoor units open as

well.

Leak test and vacuum drying should be done before the

power supply is set to the unit. If not, see "10.4. Leak test

and vacuum drying" on page 19 for more information.

Ambient temperature Humidity Minimum thickness

≤30°C 75% to 80% RH 15 mm

>30°C ≥80% RH 20 mm

WARNING

Electrical installation. All field wiring and components must

be installed by a licensed electrician and must comply with

the applicable legislation.

NOTICE

Electrical wiring work recommendations. To persons in

charge of electrical wiring work: Do not operate the unit

until the refrigerant piping is complete. "10.4. Leak test and

vacuum drying" on page 19. Running the unit before the

piping is ready will break the compressor.

DANGER: Electrical shock

See "2. General safety precautions" on page 2.