Daikin VRV IV+, Installer And User Reference Manual

Page: 61 / 168

6 | Installation
Installer and user reference guide
61
RYYQ+RYMQ+RXYQ8~20U7Y1B
VRV IV+ heat pump
4P546228-1A – 2019.10
Valve State of valve
Liquid line stop valve Close
Gas line stop valve Close
Equalising line stop valve Close
NOTICE
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
"6.5.1 About checking the refrigerant
piping" [
4
59]).
6.5.4 To perform a leak test
The leak test must satisfy the specifications of EN378‑2.
To check for leaks: Vacuum leak test
1 Evacuate the system from the liquid and gas piping to –⁠100.7 kPa (–⁠1.007 bar)
(5 Torr absolute) 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.
To check for 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 operation pressure of the unit, i.e. 4.0 MPa (40 bar).
2 Test for leaks by applying a bubble test solution to all piping connections.
3 Discharge all nitrogen gas.
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).
6.5.5 To perform vacuum drying
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
"6.5.1 About checking the refrigerant piping" [ 4 59] for more
information.
To remove all moisture from the system, proceed as follows: