Air Tight Test And Vacuum Drying; To Insulate The Refrigerant Piping - Daikin VRV W T Serie Manual De Instalación

5 Installation
NOTE
Do not connect the vacuum pump to the suction gas stop
valve if the unit is intended to run in heat pump mode. This
will increase the risk of unit failure.
Valve
Valve A
Valve B
Valve C
Valve D
Liquid line stop valve
Gas line stop valve
High pressure/low pressure gas
line stop valve
NOTE
The connections to the indoor units and all indoor units
should also be leak and vacuum tested. Keep any possible
(field supplied) field piping valves open as well.
Refer to the indoor unit installation manual for more details.
Leak test and vacuum drying should be done before the
power supply is set to the unit. If not, see also the flow
chart earlier described in this chapter (see
checking the refrigerant piping" on page
5 .4 .4

Air tight test and vacuum drying

▪ After finished piping work, carry out air tight test and vacuum
drying.
NOTE
▪ Always use nitrogen gas for the air tightness test.
▪ Absolutely do not open the stop valve until the main
power circuit insulation measurement has been
completed. (Measuring after the stop valve is opened
will cause the insulation value to drop.)
<Needed tools>
Gauge manifold ▪ To prevent entry of any impurities and insure
Charge hose sufficient pressure resistance, always use the
valve special tools dedicated for R410A.
▪ Use charge hose that have pushing stick for
connecting to service port of stop valves or
refrigerant charge port.
Vacuum pump ▪ The vacuum pump for vacuum drying should
be able to lower the pressure to 500 microns.
▪ Take care the pump oil never flow backward
into the refrigerant pipe during the pump stops.
NOTE
▪ The air-tightness test and vacuum drying should be
done using the service ports of suction gas pipe, high/
low pressure gas pipe and liquid pipe stop valve. See
the [R410A] Label attached to the front panel of the
outside unit for details on the location of the service
port.
▪ See "5.6.4 To charge refrigerant" on page 28
on handling the stop valve.
▪ The refrigerant charge port is connected to unit pipe.
When shipped, the unit contains the refrigerant, so use
caution when attaching the charge hose.
Installation manual
24
State of valve
Open
Open
Open
Open
Close
Close
Close
"5.4.1 About
23).
for details
<Air tight test>
Pressurize the suction gas pipe, high/low pressure gas pipe and
liquid pipe from the service ports of each stop valve to 3.8 MPa (550
psi) (do not pressurize more than 3.8 MPa (550 psi)). If the pressure
does not drop within 24 hours, the system passes the test.
If there is a pressure drop, check for leaks, make repairs and
perform the air tight test again.
<Vacuum drying>
Evacuate the system from the suction gas pipe, high/low pressure
gas pipe and liquid pipe stop valve service ports 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 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.
NOTE
During the rainy season, moisture might enter the
piping . If working during a rainy season and the work
takes long enough for condensation to form inside the
pipes, take the following precautions:
After evacuating the system for 2 hours, pressurize the
system to 375,000 microns (vacuum break) with nitrogen
gas and evacuate 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 a vacuum for 1 hour,
confirm that the vacuum gauge does not rise.
5 .5

To insulate the refrigerant piping

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.
▪ Always insulate the suction gas pipe, high/low pressure gas pipe,
liquid pipe and pipe connections.
▪ Use heat resistant polyethylene foam which can withstand a
temperature of 158°F (70°C) for liquid piping and polyethylene
foam which can withstand a temperature of 248°F (120°C) for gas
piping.
▪ Reinforce the insulation on the refrigerant piping according to the
installation environment.
Ambient Humidity
temperature
≤86°F 75% to 80% RH
>86°F ≥80% RH
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, this must be prevented by sealing up the connections. See
below figure.
RWEQ96~432TATJU + RWEQ96~432TAYDU
VRV W T-Series water-cooled system air conditioner
Minimum thickness
0.6 inch
0.79 inch
4P484115-1A – 2017.10