Air Source Screw Water Chiller Unit – Installation Operation and Maintenance Manual
28
2)
Copper Pipe End Trimming
(1) Purpose
Remove the burr on pipe ends and clean the inner space of pipe. In this way, no scratch will
occur on the sealing interface during pipe end expansion.
(2) Operation method
①
Use a scraper to remove the burr in the inner side of the pipe end. Slope the pipe downwards;
otherwise, copper cuttings may enter the pipe.
②
Chamfer the pipe, and then use cotton gauze to clean the copper cuttings inside the pipe.
③
Do not make any scratches. Otherwise, the pipe may break during end expansion.
④
Cut the part that is severely deformed and start from a new end.
3)
Pipe Expanding
1.
Purpose: Expand the pipe end to enable the insertion of copper pipe. In this way, less soldering
point is required.
2.
Note: Parts for connection must be smooth. Remove the burrs in the inner side of pipe end.
3.
Operation method: Insert the head of the pipe expander into the pipe. After the pipe is expanded,
view the copper pipe from another angle and maintain the pipe end and left a straight line mark.
6
.3.2.9 Soldering
Nitrogen protection during copper pipe soldering
1)
Purpose: Prevent the generation of oxide skin inside the copper pipe due to high temperature.
2)
Disadvantages of soldering without nitrogen protection:
Without sufficient nitrogen being filled into the refrigerant pipe that is being brazed, the inner surface of
copper pipe will be oxidized. The generated oxide will block the refrigerant system and deteriorate the
lubricant in the compressor. As a result, the compressor will burn and the performance of air conditioner
will decrease.
Therefore, nitrogen must be filled into the refrigerant pipe continuously during soldering. Ensure that the
nitrogen flow can reach every soldering point until the soldering is finished and the copper pipe returns to
the ambient temperature. Set the nitrogen pressure appropriately. Excessive pressure may cause bubble
