Daikin VRV REYQ96MTJU Design, Installation & Testing Instruction page 39

Si39-406
Checking for [Check 1] (Where pressure falls while carrying out Steps 1 to 3 described on previous page)
Leaks
[Check 2] (When searching for a minor leak or when there has been a fall in pressure while the
system has been fully pressurized but the source of the leak cannot be traced.)
1. Release the nitrogen until the pressure reaches 13.05psi.
2. Increase pressure to 217psi using gaseous flon gas (R410A). (Nitrogen and flon gas mixed)
3. Search for the source of the leak using a leak detector.
4. If the source of the leak still cannot be traced then repressurize with nitrogen up to 551psi and
Setup of Air-tight Test
As for the air-tight test, the setup of devices shown in the following figure is recommended with
considerations given to "vacuum drying and refrigerant additional charging", which are operation
steps following the air-tightness test.
In order to conduct the air-tight test, with stop valves of 8.Gas side, 10.liquid side and 15.Oil
equalization piping and those of the refrigerant and vacuum pump all closed, then open the
nitrogen gas stop valve, 7.Valve A, 8.Valve B and 17. Valve C while adjusting the nitrogen gas
pressure regulating valve, thus increasing the pressure.
General Information
24 hours later: 543psi 68°F
The pressure drop in such a case is deemed to be zero (successful test).
550
500
psi
450
400
350
300
250
200
150
100
50
0
Check by ear......Listen for the sound of a major leak.
Check by hand......Check for leak by feeling around jointed sections with hand.
Soap and water check (∗Snoop)......Bubbles will reveal the presence of a leak.
check again. (The pressure must not be increased to more than 551psi.)
551psi
217psi
13.05psi
Installation
33