hey guys I'm up on the roof today we're putting in a mini split and one of the questions I get
all the time is proper vacuum in procedure so I'm gonna go over today just the proper vacuum
procedure of a mini split machine and we're also gonna pressurize it with nitrogen before we do
that so I'm going to show you the proper steps to get by that so right now we've got gauges hooked
to the machine and you can hook into either line if you got two fittings and four ports on your
gauges you can hook it to both lines if you have two ports some machines have two some have one
I've got my yellow line hooked to my nitrogen tank I've got it laid to the side just because a roofs
not flat it's phone roof and wants to roll around so those y'all was wondering about that that's why
so what what am i do is I'm gonna pressurize this thing with nitrogen and we're gonna fill it up and
there's not an exact amount of nitrogen you got to put in it 200 250 350 anywhere in that range
the biggest thing you want to see is that it holds that amount whatever you put in there so right now
we're at 360 and it's got to go through both lines and the indoor machine so whenever you do it just
make sure you find you a good number and try to keep it there so I'm uh you can work on 400 here
alright 403 let's let it settle and what we're gonna do is you just find your number and you
just let it sit and again this is a I just got hooked to my adapter and then we're going to
let it sit for like 15 minutes and we'll come back to it and the next step will after it holds
pressure we'll hook the vacuum pump up to it and I'll show you that procedure okay so we're gonna
give it 15 minutes now or 10 minutes and we'll see what pressures do and I'll show you how to
do that so now just sit and wait alright we back at it and you'll see it bounces around
a little bit as the temperature moves but it's still holding the same so now what I'm gonna do
is I'm gonna cut my tank off cut your tank off valves closed that's close we'll remove
the yellow line and now I'm just gonna start bleeding all that nitrogen off so I'm open
I'm gonna believe this knife is you know the system and it's pretty important you see how
long it's taken if some reason you open that hose up and only takes a split second what I've seen
in the past is these fittings here especially if you have a new fitting if they're a new fitting
the rubbers are new then they don't depress the valve core in here and if that valve core don't
depress you're not getting nitrogen through here it's only pressurizing from here back so
anytime you do a vacuum or anything and it just takes a short time and hey it's tight and you
know it only took ten seconds to do that's the reason check your fitting especially if you have
a new fitment you have to tighten it up with a valve or can fit so anyway we're about out and
my next step I got extension cord up here but my next step is and you see always regardless
whether a hold a long time and no problem or not I still take the soap bubbles any type of soap
thick soap put around all my fittings even my fittings and my gauges so anyway I'm gonna get
some power up here then we're going to proceed with the vacuum so I'll show you that part next
alright guys I got my back in pop hooked up and it's connected my yellow hose I've got it turned
on valve on my lines on I've got this on it's pumped down into 29 inches of mercury now hadn't
got deep enough for my microns to start mine has a built-in micron gauge some you got regular set
of gauges you might have to have a separate micron gauge but wait for the microns to get down around
500 microns and I know we're in a deep vacuum and I know all non-condensibles out I've got a
blue hose you can use blue or red mine it really don't matter as long as I know what pressures
I'm reading so I got my blue hose hooked to my service port the service port is open and now
we're sucking from this point back to the whole air handler back to this point here so we're gonna
allow it to suck for a while and you'll hear the actual vacuum pump as it gets down into a deeper
vacuum you'll hear it it actually get lower and lower and quieter and quieter and as this vacuum
falls we'll start reading my claws and now here we go now it's going to start reading microns
before it was infinity because with it wasn't in that deep of vacuum so right now is starting
to fall and I'm gonna give it about 30 minutes and we'll come back to it and I'll show you what we're
what we're falling to and as time progresses that it just keep dropping and dropping and dropping
once I get down to around 500 microns I know there's no non-condensibles of moisture left in
the system all right guys you can hear how quiet it is now and we're down to 349 so she's holding
and matter of fact the valve is off so we can go ahead and just shut that off and we'll come over
here to the service valves and one thing about the service valves you need to remember is trying to
always open the largest one first reason being is the floor refrigerant the txp valves in this one
so you want to flow the refrigerant come through here and not all through your TX v valve at one
time so now we're going to open so we want to open it since I found it right Allen wrench it's
a metric do this with one hand here hey we're good we're gonna open the valves up largest one first
and open it all the way don't crack it and it's got to stop you'll feel it when it hits - stop
right there in the next one let it get to the stop and that's it another important thing is
whenever you put these on don't use any Teflon Teflon to get in system and destroy it the
flare seals not the threads so snug these down and that's it you ready to fire it up