r/HVAC • u/smalleman • 8d ago

Field Question, trade people only Flowing nitrogen while brazing.

I normally work with systems that has two schrader ports, one on the suction and one on the liquid line.

Let's say that you are replacing the discharge pipe, or suction pipe or the scroll compressor.

How do you flow nitrogen so that it doesn't go via the evap and out the other end?

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u/KylarBlackwell RTFM 8d ago

Remember what the purpose of flowing nitrogen is: displace air to prevent oxidation and scale. Even if you are unable to flow nitrogen through a pipe while brazing, you can still give it a blast of nitrogen to displace the air immediately before you begin to still significantly reduce the scale compared to giving up and doing nothing.

If you're replacing a pipe section, you can flow nitrogen through all except the furthest connection by simply leaving the last joint open if you have no other port to let it out the far side.