21
4.5.3 Tubing Connections
Indoor coils have only a holding charge of dry nitrogen.
Keep all tube ends sealed until connections are to be
made.
• Use type “L” copper refrigeration tubing. Braze the
connections with the following alloys:
– Copper to copper, 5% silver minimum
– Copper to steel or brass, 15% silver minimum
• Be certain both refrigerant shutoff valves at the
outdoor unit are closed.
•
Remove the caps and Schrader cores from the pressure
ports to protect seals from heat damage. Both the
Schrader valves and the service valves have seals that
may be damaged by excessive heat.
•
Clean the inside of the fittings and outside of the tubing
with a clean, dry cloth before soldering. Clean out
debris, chips, dirt, etc., that enters tubing or service
valve connections.
•
Wrap valves with a wet rag or thermal barrier compound
before applying heat.
•
Braze the tubing between the outdoor unit and indoor
coil. Flow dry nitrogen into a pressure port and through
the tubing while brazing, but do not allow pressure inside
tubing which can result in leaks. Once the system is full
of nitrogen, the nitrogen regulator should be turned off to
avoid pressuring the system.
• A
fter brazing, use an appropriate heatsink material to
cool the joint.
• Reinstall the Schrader cores into both pressure ports.
• Do not allow the bare vapor line and liquid line to be in
contact with each other. This causes an undesirable
heat transfer resulting in capacity loss and increased
power consumption.
Tubing
4.0 INSTALLATION
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