Question on Nitrogen test requirements

My manufacturer (Pioneer) does not mention the nitrogen test in its install manual, but as referenced below, a longer install video says the pressure can be different for the inside unit than the outside, so he recommends 300 PSI for all mini-splits.

It is these kinds of questions that are not spec'd in the manual that make doing this the first time so hard. I guess this is one reason a lot of guys apprentice. I do like the tip of doing smaller PSI tests first.

So, when you say this "I leave the liquid port loose and start the nitrogen flow till I hear it hiss at the valve, shut off the nitrogen and then torque the liquid line to spec. This takes very little gas and is unprofessional but I now know I have an open system."

The lines are empty, so this way you also know you are filling the whole line set, not just the hose. I just saw a message a from a DIY who said when he did the vacuum he forgot to open the lineset, so he just vacuumed his hose.

THOSE are the things that are logical, but potential pitfalls for people who have never done it.

This recommended longer install video is good because he does mention every small step he does along the way.

Thanks for the info on where to get nitrogen. I did watch the triple evac video - understood.My manufacturer (Pioneer) does not mention the nitrogen test in its install manual, but as referenced below, a longer install video says the pressure can be different for the inside unit than the outside, so he recommends 300 PSI for all mini-splits.It is these kinds of questions that are not spec'd in the manual that make doing this the first time so hard. I guess this is one reason a lot of guys apprentice. I do like the tip of doing smaller PSI tests first.So, when you say this "I leave the liquid port loose and start the nitrogen flow till I hear it hiss at the valve, shut off the nitrogen and then torque the liquid line to spec. This takes very little gas and is unprofessional but I now know I have an open system."The lines are empty, so this way you also know you are filling the whole line set, not just the hose. I just saw a message a from a DIY who said when he did the vacuum he forgot to open the lineset, so he just vacuumed his hose.THOSE are the things that are logical, but potential pitfalls for people who have never done it.This recommended longer install video is good because he does mention every small step he does along the way.