Installed Used Mini-Split But I Think I Leaked Out All Refrigerant

[queequeg152]

I SHOULD MENTION:
When I first released refrigerant into the system by opening stem valve, I had a blast of pressure come out the low side flare nut because I apparently didn't tighten the flare nut enough. I quickly closed the valve and took a wrench to the flare nut immediately before too much refrigerant could leak out. I was surprised the AC worked for 24 hours ice cold before crapping out. This tells me I didn't leak all my refrigerant out with that initial release? But maybe the leak could be at the low side flare nut outside and I plan to use nitrogen to verify. You can see what looks like a wet spot under the low side ports. I think the r410a stained the concrete from when the refrigerant blasted out the flare nut from 5 nights ago?

wet spot it probably oil.

keep in mind r410 is a mixture of refrigerants with different boiling points.

when you leak vapor you typically leak more of one refrigerant than the other causing the ratio of r32, r125 etc to change.

basically when you leak vapor, you need to recover the charge and weigh in a new charge.


put your gauges on the unit and see if there is any pressure.

if you have any pressure, do a fast leak check with some soapy water.

the leak is probably at a flare nut. this is where probably 95% of minisplit leaks are at.

find the bad flare, cut it off and reflare the copper with a decent flaring tool. hilmore makes a good one.

while you are at it, cut off all that fucking extra lineset length. what is that bullshit?

alternately you can just swage and braze or even soft solder the connection.

if you dont find any leaks with what little pressure is left... recover the charge and pressurize it with nitrogen and do the leak check again.

do not vent the remaining charge of refrigerant. recover it with a proper machine.

only shit bags vent to atmosphere.

 

[MrBungle]

yea that wet spot is an oil stain... it looks like you lost your charge thru the low side flare nut....there was probably enough refrigerant for it to run with that small loss when you opened the stem valve but as the system ran pressurized over that 24 hour period you probably lost the charge or most of it... to be safe I would recover whatever is left in the system and weigh in a fresh charge...

I learned some things today too thanks Old Phart and Quee

I was reading about fractionalization and 410a.... it doesn't have much temp glide for a refrigerant mixture.. but like you said... the leak being most likely on the low side... would give the different gases a chance boil off separately

 

[the gnome]

wet spot it probably oil.
while you are at it, cut off all that fucking extra lineset length. what is that bullshit?
alternately you can just swage and braze or even soft solder the connection.

yes, it's oil, many times you can locate a leak by feeling the oil at places where the line is connected together
there's a very good reason these units come with flare fittings
AND
extra lineset

when working with minisplits copper lines do NOT braze ANY fitting unless you're running an inert gas in the lines like nitrogen that will negate the formation of crap inside the line.
without it and brazing can get that black soot/ash inside the line and that shit breaks loose easily,
you can imagine the tight specs with minisplit innards and crap breaking loose floating thru the system.
there's a metering device thats extremely sensitive to any debris
floating thru it and is usually the 1st thing to gets clogged.
it doesn't take much of anything messing with this component
and you'll need a service tech or someone that kno's
his stuff to get it back on track,
not to mention down time and people messing around your grow op


as far as extra line set it's seems self explanatory.
but be aware DIY's
any length cut off needs to be re-fitted with a flair and measure what was cut, as most know MS's r410 is weighed in by length of line.

 

[newguy41410]

Ok guys, had to take a break from trying to fix the AC as some family problems came up.

Had some time so today, i went out to hook up my manifold gauge up to the outdoor unit and it is giving me a pressure reading of only 36 PSI. So i have definitely leaked out most of my refrigerant. I think this chart (taken from web site that sells my mini split) says i should be reading about 125 PSI when its about 75 degrees farenheit in my growroom and outside, correct??

https://www.highseer.com/pdf/Temperature-Pressure-Chart.pdf

I wanted to do a pressure test using nitrogen so first I pumped down whatever refrigerant i had left into the outdoor unit and shut off both low side and high side valve stems, and then used a nitrogen tank to introduce about 250 PSI of nitrogen into the line sets. It has been about 9 hours since and pressure is still at 250 PSI.

At this point, i am going to sleep and then when i wake up i plan to do a triple evacuation using nitrogen [since i have a cheap harbor freight pump (not sure how to do triple evac yet need to do some googling)]


after triple evacuation, I'll need to add refrigerant.. Can i just add refrigerant until i get a specific PSI as indicated in the chart i linked above?? In other words can i keep adding refrigerant until i get about 125 PSI and then stop charging??

someone mentioned i need to recover what ever little refrigerant i have left before adding a new charge... but wouldn't that really need purchasing of a recovery tank? i really dont want to spend much more on things i wont be using so often. im hoping i can just use PSI readings to have a good idea of whether my system has enough refrigerant or not? Thanks for all your help so far it has been greatly appreciated!

PS - im using high side (red side) of manifold gauge because the blue side gauge only goes up to 120 psi

 

[OldPhart]

Had some time so today, i went out to hook up my manifold gauge up to the outdoor unit and it is giving me a pressure reading of only 36 PSI. So i have definitely leaked out most of my refrigerant. I think this chart (taken from web site that sells my mini split) says i should be reading about 125 PSI when its about 75 degrees farenheit in my growroom and outside, correct??

https://www.highseer.com/pdf/Temperature-Pressure-Chart.pdf

I wanted to do a pressure test using nitrogen so first I pumped down whatever refrigerant i had left into the outdoor unit and shut off both low side and high side valve stems, and then used a nitrogen tank to introduce about 250 PSI of nitrogen into the line sets. It has been about 9 hours since and pressure is still at 250 PSI.

At this point, i am going to sleep and then when i wake up i plan to do a triple evacuation using nitrogen [since i have a cheap harbor freight pump (not sure how to do triple evac yet need to do some googling)]


after triple evacuation, I'll need to add refrigerant.. Can i just add refrigerant until i get a specific PSI as indicated in the chart i linked above?? In other words can i keep adding refrigerant until i get about 125 PSI and then stop charging??

someone mentioned i need to recover what ever little refrigerant i have left before adding a new charge... but wouldn't that really need purchasing of a recovery tank? i really dont want to spend much more on things i wont be using so often. im hoping i can just use PSI readings to have a good idea of whether my system has enough refrigerant or not? Thanks for all your help so far it has been greatly appreciated!

PS - im using high side (red side) of manifold gauge because the blue side gauge only goes up to 120 psi

I think it is time to call in a pro. You don't have any appreciable amount of coolant left in the system at 36 PSI, so there is nothing to recover. No you can not use the pressure to set the charge level on the system, it needs to be weighed in. I would open the valves up since there is really nothing left in the system and see if there are leaks in the condensing unit. You are isolating the system from the nitrogen bottle while pressure testing, right?

 

[MrBungle]

unfortunately charging to a specific psi won't do it.. It is possible to charge without a scale its just kinda complicated...

 

[newguy41410]

I think it is time to call in a pro. You don't have any appreciable amount of coolant left in the system at 36 PSI, so there is nothing to recover. No you can not use the pressure to set the charge level on the system, it needs to be weighed in. I would open the valves up since there is really nothing left in the system and see if there are leaks in the condensing unit. You are isolating the system from the nitrogen bottle while pressure testing, right?

unfortunately charging to a specific psi won't do it.. It is possible to charge without a scale its just kinda complicated...

OK, so after I pumped down the outdoor unit down to 0 PSI i closed the valve and left the gauge on for about 15 minutes to make sure that the pressure did not climb. So this is one indication my condensing unit isn't leaking correct? i also woke up to find the gauge still read 200 psi. I also opened up both valve stems and introduced more nitrogen to reach 200 psi, and it was able to hold the 200 psi for fifteen minutes.

With this all true, is it safe to say I'm leak-free?

If so, I'm thinking about just taking my outdoor unit to the local HVAC shop instead of having them come to my place and see my grow. I can just take my ODU to them and ask them to charge ennough r410a for X amount of line set, no
questions asked, correct?

 

[MrBungle]

I don't think it will work that way.... they will want to know whats going on... it could make them liable if there was an accident or something of that nature...not to mention those valves can be leaky after they have been opened and closed a few times

 

[queequeg152]

if you cannot afford the tools to work on hvac equipment, you should not be working on hvac equipment.

if you dont want to buy the tools to do the job properly you need to hire a professional.
a charging cylinder is like 100 bucks, and a recovery machine starts around 300-400 bucks. i bought mine used for around 200 bucks.

you dont even necessarily need a recovery unit btw. you can pump down the liquid into a recovery tank using the condensing unit compressor itself. look up this procedure. all you need is a vacuum pump to evacuate the recovery tank. also look up the units manual and make sure to follow any recovery instructions they offer.

this is not a good way to avoid refrigerant releases... its not even a legal EPA procedure for 410, but its better than venting it to the atmosphere. normally after you pump the liquid out, you would then hook up a recovery machine to recover the vapor... but since you dont have one and dont want to buy one... you would vent the remaining vapor.

but your cheapest non tool buying bet would be to haul the condensing unit itself to a professional to recover what little charge is left. again though a recovery tank is only like 100 bucks. do not run the system into a vacuum. a hermi scroll or hermi rotary compressor does not want to run itself into a deep vacuum.

also do not weigh in any charge untill you find the fucking leak.
this should be obivious, but its not clear to me what you are proposing to do to find the leak?

after you recover the charge you need to pressurize the whole system with ntirogen and leak check.

after you find the leak you are probably going to need to reflare the copper. buy a real flaring tool and copper cutting tool to do this.

after you do all of then THEN triple evac with your vacuum pump down to what ever microns the manufacturer wants.

then charge to what ever weight the manufacturer wants.