Refrigerant Piping Precautions; Nitrogen Purging While Brazing - Trane 25 Series Installer Manual

Refrigerant Piping Precautions

Hazard of Explosion and Deadly Gases!
Failure to follow all proper safe refrigerant handling practices could result in death or
serious injury. Never solder, braze or weld on refrigerant pipes or any unit components
that are above atmospheric pressure or where refrigerant may be present. Always
remove refrigerant by following the guidelines established by the EPA Federal Clean
Air Act or other state or local codes as appropriate. After refrigerant removal, use dry
nitrogen to bring system back to atmospheric pressure before opening system for
repairs. Mixtures of refrigerants and air under pressure may become combustible in the
presence of an ignition source leading to an explosion. Excessive heat from soldering,
brazing or welding with refrigerant vapors present can form highly toxic gases and
extremely corrosive acids.
System Component Damage!
Do not remove the seal caps from the refrigerant connections and piping until prepared
to braze refrigerant pipes to the connections. Excessive exposure to atmosphere
(greater than 5 minutes) may allow moisture or other particulates to contaminate the
system, damaging valve seals and causing ice formation in the system components
during operation.

Nitrogen Purging While Brazing

Avoid Unit Damage!
Never braze pipe connections without performing nitrogen purging. Failure to perform
this procedure will damage the unit, resulting in capacity loss and reduced long-term
reliability.
While brazing refrigerant pipes, continuously purge them with nitrogen gas. Use a
pressure regulator to maintain a flow rate of 1.76 ft³/h (0.05 m³/h) or more.
WARNING
NOTICE
NOTICE
Nitrogen purging while brazing refrigerant pipes
Nitrogen
Pressure regulator
Stop valve
Flow meter
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25 Series Single Zone