Haier Smart Power Series Service Manual page 144

7.6 Leak test and vacuum drying
When all piping work is complete and the outdoor unit is connected to the indoor unit, it is necessary to :
• Check for any leakages in the refrigerant piping
• To perform vacuum drying to remove all moisture in the refrigerant piping.
If there is a possibility of moisture being present in the refrigerant piping (for example, rainwater may have entered
the piping) , first carry out the vacuum drying procedure below until all moisture has been removed.
7.6.1 General guidelines
• All piping inside the unit has been factory tested for leaks.
• Use a 2-stage vacuum pump with a non-return valve which can evacuate to a gauge pressure of-100.7kPa (5 Torr
absolute,-755mm Hg) .
• Connect the vacuum pump to both the service port of the gas stop valve and the liquid stop valve to increase
• Do not purge the air with refrigerants. Use a vacuum pump to evacuate the installation. No additional refrigerant is
provided for air purging.
Make sure that the gas stop valve and liquid stop valve are firmly closed before performing the leak test or
vacuum drying.
7.6.2 Leak test
The leak test must satisfy specification EN378-2.
1. Vacuum leak test
1.1 Evacuate the system from the liquid and gas piping to -100.7 kPa (5 Torr) .
1.2 Once reached, turn off the vacuum pump and check that the pressure does not rise for at least 1 minute.
1.3 Should the pressure rise, the system may either contain moisture (refer to the paragraph " Vacuum drying ")
or have leaks.
2. Pressure leak test
2.1 Break the vacuum by pressurizing 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. 4.0MPa (40bar) .
2.2 Test for leaks by applying a bubble test solution to all piping connections.
Make sure to use a recommended bubble test solution from your wholesaler.
Do not use soap water, which may cause cracking of falre 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) .
7.6.3 Vacuum drying
To remove all mositure from the system, proceed as follows:
1. Evacuate the system for at least 2 hours to a target vacuum of -100.7 kPa (=-1.007 bar) .
2. Check that, with the vacuum pump turned off, the target vacuum is maintained for at least 1 hour.
3. Should you fail to reach the target vacuum within 2 hours or maintain the vacuum for 1 hour, the system may
contain too much moisture.
4. In that case, break the vacuum by pressurizing with nigrogen gas to a gauge pressure of 0.05 MPa (0.5bar) and
repeat steps 1 to 3 unit all moisture has been removed.
5. The stop valves can now be opened, and/or additional refrigerant can be charged
After opening the stop valve, it is possible that the pressure in the refrigerant piping does not rise. This migh be
caused by e.g. the closed state of the expansion valve in the outdoor unit circuit, but does not present any problem
for correct operation of the unit.
NOTICE
NOTICE
INFORMATION
142
Smart Power