Daikin VRV II Series Design, Installation & Testing Instructions page 35

Si39-303
3.2.5 Air Tight Test
!
Essential Points
The key to successful testing is strict adherence to the following procedure:
a) The liquid and gas piping in each refrigerant system should be pressurized in turn in accordance with
of Testing
(Maintaining
!
Pressure Over a
Period)
!
!
∗
Increasing the system pressure to 3.80MPa does not guarantee the identification of minor leaks if
pressure is maintained for only a short time. It is therefore recommended that the system remain
pressurized in accordance with Step 3 above for at least 24 hours.
Note:
The pressure must on no account be increased beyond 3.80MPa.
b) Check for pressure drop
General Information
Operational steps
Pressurize
Complete
refrigerant pipe
installation work
the following steps. (Nitrogen gas must be used.)
Step 1: increase pressure to 0.3MPa for 3
minutes or more
Step 2: increase pressure to 1.5MPa for 3
minutes or more
Step 3: increase pressure to 3.80MPa for
approx. 24 hours
If there is no drop in pressure then the test is deemed a success.
If the pressure drops then the leak must be located. See following page.
However, if there is a change in the ambient temperature between the pressurizing stage and the time
when you check for a drop in pressure then you will have to adjust your calculations accordingly since a
change of 1°C can account for a pressure change of approximately 0.01MPa.
Compensating adjustment value:
(temperature at time of pressurizing – temperature at time of checking) × 0.01
Example:
Time of pressurizing: 3.80MPa 25°C
24 hours later: 3.75MPa 20°C
The pressure drop in such a case is deemed to be zero (successful test).
Check for pressure drop
Locate and repair leaks



Indicates existence of major leaks




Indicates existence of minor leaks



Installation
Success
(V0987)
29