Leak Test And Vacuum Drying; Additional Refrigerant Charge; Procedures For Adding Refrigerant - Panasonic U-4ML4DPQ Installationsanleitung

9.7. Leak test and vacuum drying

The units were checked for leaks by the manufacturer.
See figure 6 and refer to "Additional refrigerant charge" on page 10
for nomenclature of the parts in figure 6.
• Confirm that the gas and liquid line stop valves are firmly closed
before pressure test or vacuuming.
• Make sure that valve A is completely open.
Air tight test and vacuum drying
Air tight test: Make sure to use nitrogen gas. (For the service
port position, refer to "9.2. Cautions for handling stop valve" on
page 7.
Pressurize the liquid and gas pipes to 4.0 MPa (40 bar) (do not
pressurize more than 4.0 MPa (40 bar)). 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
–100.7 kPa (5 Torr, –755 mm Hg)
1. Evacuate the system from the liquid and gas pipes by using a
vacuum pump for more than 2 hours and bring the system to
–100.7 kPa. After keeping the system under that condition 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.
2. 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
0.05 MPa (vacuum break) with nitrogen gas and evacuate the
system again using the vacuum pump for 1 hour to –100.7 kPa
(vacuum drying). If the system cannot be evacuated to –100.7 kPa
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.
10. A
DDITIONAL REFRIGERANT CHARGE
Refrigerant cannot be charged until field wiring has
been completed.
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 permissible charge is never exceeded, in
view of the danger of liquid 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 charging refrigerant.
When performing service on the unit requiring the
refrigerant system to be opened, refrigerant must be
evacuated according to local regulations.
Do not use the automatic refrigerant charging function
while working on the indoor units.
When using the automatic refrigerant charging
function, the indoor units operate automatically as
well as the outdoor unit.
When the power is on, please close the front
panel when leaving the unit.
Installation manual
10
See figure 6.
1 Pressure reducing valve
2 Nitrogen
3 Tank
4 Siphon system
5 Measuring instrument
6 Vacuum pomp
7 Valve A
8 Gas line stop valve
9 Outdoor unit
10 Liquid line stop valve
11 Indoor unit
12 Stop valve service port
13 Charge hose
To avoid compressor breakdown. Do not charge the refrigerant
more than the specified amount.
This outdoor unit is factory charged with refrigerant and
depending on pipe sizes and pipe lengths some systems require
additional charging of refrigerant. See "How to calculate the
additional refrigerant to be charged" on page 9.
In case re-charge is required, refer to the nameplate of the unit.
The nameplate states the type of refrigerant and necessary
amount.
Precautions when adding R410A
Be sure to charge the specified amount of refrigerant in liquid state to
the liquid pipe.
Since this refrigerant is a mixed refrigerant, adding it in gas form may
cause the refrigerant composition to change, preventing normal
operation.
Before charging, check whether the refrigerant cylinder is
equipped with a siphon tube or not.
Charge the liquid
refrigerant with the cylinder
in upright position.

10.1. 3 procedures for adding refrigerant

Procedure 1: Adding refrigerant by using the automatic
refrigerant charging function (recommended)
How to connect the tank?
4 5
6
1 2
7
3
When the refrigerant tank is connected and the specified operation is
performed, the appropriate amount of refrigerant will be charged into
the system. After charging, the system will stop automatically. The
refrigerant must be charged according to the procedure described
below.
Charge the liquid
refrigerant with the cylinder
in up-side-down position.
1 Liquid line stop valve
2 Gas line stop valve
3 To indoor unit
4 Service port for adding
refrigerant
5 Valve A
6 R410A Tank
7 Measuring instrument
U-4~6ML4DPQ
Urban Multi air conditioner
4PW29037-1