Trane 4TXK6512G1000AA Service Manual page 138

Leak test
The leak test must satisfy specification
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).
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 .
After opening the stop valve, it is possible that the pressure in the refrigerant piping does not rise. This migeh 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.
Charging refrigerant
Important information regarding the refrigerant used
 This product contains fluorinated greenhouse gases covered by the Kyoto Protocol . Do not vent gases into
the atmopsphere .
 Evacuate Indoor Unit and interconnecting pipework to a vacuum pressure of 500 microns and hold for 15 minutes.
 The Outdoor unit is supplied with refrigerant HFC-410A (R410A) sufficient for 30m line length .
Calculate additional refrigerant to suit your line length; refer supplied Specification Sheet .
 Open the service valve at the Outdoor unit to allow refrigerant to flow throughout the system .
 For long line lengths, oil (of the correct type) should be added to the refrigerant system at the rate shown in the
Specification Date table .(see paragraph 9 .5)
 Leak check all brazed and fitted joints .
Precautions and general guidelines
 When servicing the unit requires the refrigerant system to be opened, treatment and evacuation of refrigerant
must be done in accordance with applicable legislation .
 Refrigerant can not be charged until field wiring has been completed .
Refrigerant may only be charged after performing the leak test and vacuum drying .
Notice
5 . The stop valves can now be opened, and/or additional
refrigerant can be charged .
Information