Daikin VRV Plus Series General Information Manual page 37

Si33-003.book Page 33 Monday, June 25, 2001 9:06 AM
SiE33-003
Special vacuum drying
This vacuum drying method is selected when there is a suspicion that there may be moisture in the pipes.
For example:
The special vacuum drying method is the same as the standard method except that nitrogen is introduced
into the pipes to break the vacuum on one or more occasions during the course of the operation.
[Operational steps]
1. Vacuum drying (1st time): 2 hours
2. Vacuum breaking (1st time): Use nitrogen to raise pressure to +0.05MPa.
3. Vacuum drying (2nd time): Operate the vacuum pump for at least 1 hour.
4. Carry out maintained vacuum test: 1 hour
5. Additional charge of refrigerant
6. Open stop valve to the full
∗ The gas used for the vacuum breaking operation must be nitrogen.
General Information
When moisture was discovered during the refrigerant pipe flushing operation
When there is a risk of condensation forming inside the pipes during periods of heavy rainfall
When there is a risk of condensation forming inside the pipes due to a long term of works
When there is a risk that rainwater may have entered the pipes during installation
(Since the nitrogen gas used to break the vacuum is dry nitrogen this process serves only to enhance
the overall drying effect of the vacuum drying operation itself.
However, since the effectiveness of this process is severely impaired by a high moisture level inside the
pipes, the utmost care is required during installation to see that water does not enter or form inside the
refrigerant pipes.)
(Observations: Degree of vacuum has reached 5 mmHg. If the degree of vacuum has not reached 5
mmHg after 2 hours or more then repeat the operations at 2 (vacuum breaking) and 3 (vacuum drying)
above.)
(The use of oxygen brings a serious risk of explosions)
: http://splitoff.ru/tehn-doc.html
Installation
33