Installation
Note: Insulate all refrigerant piping and connections.
Refrigerant Piping Procedures (Outdoor Units)
Each CTA unit ships with a holding charge of dry nitrogen. The nitrogen should be removed and the entire sys- tem evacuated (at the proper time) to avoid possible contamination.
1.Remove the service access panel.
2.Locate the liquid and discharge lines. Check that the piping connec- tion stubs on the valves (Figure 6) line up properly with the holes in the unit cabinet.
Figure 6
3.Locate the gauge ports on the dis- charge and liquid lines. Depress the valve core to release the nitrogen from the unit.
Note: If nitrogen is not released from the unit, there is a leak in the system. Locate the leak and repair before pro- ceeding with the installation.
4.Unbraze the tube seal caps to reveal the line braze connections.
WARNING:
Hazardous Pressures!
Coil has a nitrogen holding charge. Do not remove seal caps by heating the caps while coil is under pressure. Depress the gauge port valve cores to gradu- ally relieve nitrogen holding charge. Remove valve cores before removing the tubing seal caps. Failure to properly relieve pressure could result in death or serious injury.
CAUTION:
Equipment Damage!
Do not remove the seal caps from refrigerant connections until pre- pared to braze refrigerant lines to the connections. Excessive expo- sure to atmosphere may allow moisture or dirt to contaminate the system, damaging valve seals and causing ice formation in sys- tem components.
5.Cut, fit and braze tubing, starting at the outdoor unit and work toward the indoor unit.
Note: Use long radius bells for all 90 degree bends.
All brazing should be done using a 2 to 3 psig dry nitrogen purge flowing through the pipe being brazed (Figure 6).
WARNING:
Hazardous Pressures!
When using dry nitrogen cylin- ders for pressurizing units for leak testing, always provide a pressure regulator on the cylinder to prevent excessively high unit pressures. Never pressurize unit
above the maximum recom- mended unit test pressure as specified in applicable unit litera- ture. Failure to properly regulate pressure could result in a violent explosion, which could result in death or serious injury or equip- ment or
CAUTION:
Equipment Damage!
6.Shut off nitrogen supply.
7.Shut off the manifold valve for the line that is connected to the dis- charge line gauge port.
Figure 7
Refrigerant Piping Procedure (Indoor Unit)
Once liquid and discharge lines are complete to the refrigerant connec- tions on the indoor unit, depress the gauge port valve cores on the suction and discharge lines to gradually relieve nitrogen holding charge.
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