Quote:
Originally Posted by funola
Why Nitrogen? Here's a table of densities and molecular weights Gases - Densities of some common gases. Molecular weight of Helium is 4, Nitrogen is 28, air is 29.
Wouldn't Helium be best finding leaks?
If you do not have Nitrogen, wouldn't air be just as good since it is very close to Nitrogen in molecular weight? Air is 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide. Air has some moisture in it. Not a big deal if you change the Receiver/dryer to a new unit after pressure testing with air, before evacuating. Thoughts?
Edit: The new receiver/dryer connections will not be pressure tested but will be vacuum tested. A chance you'll have to take if you do not have Nitrogen. |
Nitrogen is available as a DRY gas.. so using it to pressure test also means as it is taken out some moisture is removed.. in home HVAC servicing it is common practice to put nitrogen in three times and take it out ...as a moisture removing procedure..
I think Nitrogen is cheaper than helium ... but argon will also work.. helium left over could be used for balloons BUT be careful.. the helium packaged for that is different from that for welding.. and you do not want to INHALE the wrong one being funny.... as one does not have the gases which tell your body to take in the next breath...
If you use nylog of the proper color and tighten the joints using two wrenches.. you should not have a testing difference between helium and nitrogen...