Daikin VRV 5-S Series - 19.3 Precautions When Charging Refrigerant

18 | Piping installation
Installer and user reference guide
94
RXYSA4~6A7V/Y1B
VRV 5-S system air conditioner
4P600330-1D – 2023.02
B Valve B
C Valve C
Valve Status
Valve A Open
Valve B Open
Valve C Open
Liquid line stop valve Close
Gas line stop valve Close
NOTICE
Indoor units should also be leak and vacuum tested. Keep any possible (field
supplied) field piping valves open as well.
18.3.4 To perform a leak test
Vacuum leak test
1 Evacuate the system from the liquid and gas piping to a gauge pressure of
–⁠100.7kPa (–⁠1.007bar) for more than 2 hours.
2 Once reached, turn off the vacuum pump and check that the pressure does
not rise for at least 1 minute.
3 Should the pressure rise, the system may either contain moisture (see vacuum
drying below) or have leaks.
Pressure leak test
1 Break the vacuum by pressurising with nitrogen gas to a minimum gauge
pressure of 0.2 MPa (2 bar). Never set the gauge pressure higher than the
maximum working pressure of the unit, i.e. 3.52MPa (35.2bar).
2 Test for leaks by applying a bubble test solution to all piping connections.
3 Discharge all nitrogen gas.
NOTICE
ALWAYS use a recommended bubble test solution from your wholesaler.
NEVER use soap water:
▪ Soap water may cause cracking of components, such as flare nuts or stop valve
caps.
▪ Soap water may contain salt, which absorbs moisture that will freeze when the
piping gets cold.
▪ Soap water contains ammonia which may lead to corrosion of flared joints
(between the brass flare nut and the copper flare).
To check for leaks after charging refrigerant
After charging refrigerant in the system an additional leak test must be performed.
Refer to "19.8To check for refrigerant leaks after charging"[4103].