REQ71+10 REQ71~125B7W1B
Split System air conditioners
4PW19495-1B
Installation manual
8
C
HARGING
REFRIGERANT
Precaution for servicing
This unit requires additional charging of refrigerant according to the
length of piping connected at the site. Charge the refrigerant to the
liquid pipe in its liquid state. Since R-410A is a mixed refrigerant, its
composition changes if charged in a state of gas and normal system
operation would no longer be assured.
On this model it is not necessary to charge additionaly if the piping
length
≤
7.5 m.
Additional charging of refrigerant
■
Over 7.5 m, please add refrigerant quantity according to the
following table.
For future servicing, mark with a circle the selected amount on the
table below.
Additional charging amount <unit: kg>
Total charging weight of the refrigerant (after a leak,
etc.)
When the entire refrigerant pipe length is within 7.5 meters, charge
the refrigerant in accordance with the amount mentioned in the
nameplate, and when the pipe length exceeds 7.5 meters, the
charging amount mentioned in the nameplate and that required for
additional charging are to be totalled as the net charging amount.
Precaution for pumping-down operation
The outdoor unit is equipped with a low-pressure switch to protect the
compressor.
Take the following steps to perform the pumping-down operation.
This is the end of pumping-down operation. After pumping-down
operation, the remote controller can show the following:
-
"U4"
-
blank screen
-
indoor fan operates for about 30 seconds
Even when the ON button on the remote controller is pressed, it will
not operate. Turn off the main power supply switch and turn it on
again in need of operation.
NOTE
Following should be executed if there is a possibility of
moisture remaining in 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.
After air purging with a vacuum pump it may happen that
the refrigerant pressure does not rise, not even if the stop
valve is opened. Reason for this phenomenon is the closed
state of for instance the expansion valve in the outdoor unit
circuit, but this is not a problem for running the unit.
When performing service on the unit requiring the
refrigerant system to be opened, refrigerant must be
evacuated according to local regulations.
NOTE
Piping length is the 1 way length, gas or liquid.
Connected piping length is between
Class
7.5~30 m
30~40 m
40~50 m
71
+0.20
+0.70
+1.20
100+125
+0.10
+0.60
+1.10
NOTE
In case of complete recharge of the refrigerant, please first
execute vacuuming. Execute this vacuuming from the
service port. Do not use the port of the stop valve for
vacuuming. Vacuuming can not be executed completely
using such port.
Position of service port:
Heat pump units have 2 ports on the piping. One
between the liquid receiver and the electronic
expansion valve and another one between the heat
exchanger and the 4-way valve.
NOTE
Never short-circuit the low pressure switch in this
operation.
Procedure
Precaution
1
Put a pressure gauge at the
service port of the gas stop
valve.
Use a pressure gauge
reserved for R-410A
exclusively.
2
Start the fan operation with the
remote controller.
Confirm that stop valves both
on the liquid and gas side are
open.
3
Push the pumping-down
button on the PC board of the
outdoor unit.
Compressor and outdoor fan
will start operation
automatically.
If step 3 is performed before
step 2, then the indoor fan
may automatically start
running. Please pay attention
to this.
4
Continue operation for
2 minutes until operation
condition stabilizes.
—
5
Close the stop valve on the
liquid side securely. (See
to use the shut-off valve" on
page 6
)
Insecure closing of the valve
may result in burning of the
compressor.
6
When the low-pressure switch
is activated, the unit stops
working. At this time, close the
stop valve on the gas side.
—
