Once the brazing operation of refrigeration lines is completed, the field-brazed connections must
be checked for leaks:
1. Pressurize the system with clean nitrogen 200 and 400 psig.
2. Monitor the pressure for 15–30 minutes. Use soap bubbles or alternate methods of leak-
checking for all field brazed joints.
3. After completing the leak check, evacuate the interconnecting lines to hold a 350-micron
vacuum for 15–30 minutes.
If gauge pressure rises above 500 microns in one minute, then evacuation is incomplete or
the system has a leak.
Table 3: Recommended refrigerant line sizes
Less than 75 linear feet
Model number
Liquid line
Suction line
DSH024C
3/8
3/4
DSH036C
3/8
3/4
DSH048C
1/2
7/8
DSH060C
1/2
7/8
DSH096C
2 X 1/2
2 X 7/8
DSH120C
2 X 1/2
2 X 7/8
Note:
Measurements are in inches
Model DSH024C–120C Horizontal R-410A Air Conditioning Units C-Generation Smart Equipment Controller
18
Johnson Controls
