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

I bought a 1 ton Pioneer Mini Split Used on Craigslist for 250. I was present when the HVAC guys recovered the refrigerant and helped disassemble the mini split system for me to take home from the seller's house. The seller ended up buying 3 Daikin mini splits to replace the 3 Pioneer mini splits he was selling.

I took one of the systems he was selling home with the same line set he used and installed everything (piping and electrical). I hooked up a harbor freight vacuum pump up to the service port and let it vacuum for about three hours before releasing the refrigerant.

Went in to check and every thing worked perfectly. It worked fine for about 24 hours. Then the next day i heard what sounded like the sound of ice forming. I then noticed that the liquid high side tubing was frosting up and had what appeared to have lots of icy snow-like stuff forming where the flare nut is. So i powered it off immediately and began research. Apparently, I either have a leak or a restriction forming from moisture or something in the lines.. Still haven't pinpointed reason but i plan to.

I went to sleep woke up and tried turning the ac unit on again now that the ice had melted. This time the ice didn't show up but instead there was a layer of icy frost. I turned the temperature to its lowest setting to see what it was pushing out and it feels like its just pushing out ambient air. Now i'm REALLY Sad.

Next day i try again and this time instead of a pretty thick layer of frost its basically just ice cold condensation but still blowing out ambient air.

I tried turning the heat on to the max 86 degrees and it is also ambient air.

So my GUESS is the refrigerant all leaked out. And if i were to guess the leak or the restriction is in the area of that one flare nut. Does it sound like i obviously had a leak? I am leaning toward that notion myself and would like to confirm.

At this point i am thinking about buying a nitrogen regulator and bringing home a nitrogen bottle from work to do a leak test. And if i have a leak and can fix it, i will order a bottle of refrigerant from ebay and charge it myself.

Just wondering if there is anything I may be overlooking?

To fix it, i think im going to need to purchase about 200 dollars worth of tools (50 dollar nitrogen pressure regulator, 150 dollar micron gauge). i already have a harbor freight 2.5 cfm single stage vacuum pump, mastercool flaring tool and manifold gauges.

More than likely the refrigerant leaked out, before vacuuming out you should do the pressure test with nitrogen and gauges. Varies on each unit but usually you put about ~200 pounds of pressure in the system and let it sit for an hour or so to be sure pressure stays. If its losing pressure use soap and water to find the leak.

Once that is done you should use a 2 stage vacuum pump and gauges and pump for a few hours, let sit for an or hour so after you turn the pump off and turn line on gauges off that goes to the pump to make sure the vacuum holds, which it should if the pressure test was successful. Then when all is good you can release the refrigerant into the line set.

Those flare connections can suck.. I had to reflare one of the ends on my mini split when I installed it as one end just would not seal and would fail the pressure test over and over.. finally was able to get it to seal and hold pressure/vacuum after redoing the flare connection a couple times.

linky said:

Those flare connections can suck.. I had to reflare one of the ends on my mini split when I installed it as one end just would not seal and would fail the pressure test over and over.. finally was able to get it to seal and hold pressure/vacuum after redoing the flare connection a couple times.

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They really do suck, I wish they would give the option for brazing, just have a copper tube sticking out to braze onto the line set. Not like I'm a pro, but on that small of tubing, if you get it good and clean, use a turbo torch with MAP gas, and an appropriate stick of silfos... it really isn't that hard. I've brazed up a few systems, and had no leaks at all.

Gotta pressure test w the nitrogen. Your vac pump likely not up to the challenge. Either get a 2 stage pump or Get the micron gauge to see where it gets you.

did you open the valves at the condensing unit?

Thank you for all your responses!!

linky said:

Those flare connections can suck.. I had to reflare one of the ends on my mini split when I installed it as one end just would not seal and would fail the pressure test over and over.. finally was able to get it to seal and hold pressure/vacuum after redoing the flare connection a couple times.

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Curious what kind of flaring tool you used? I used the flaring tool on only 1 tip of the high side line i didn't flare all 4 ends of tubing. I thought it was a pretty flawless flare i am thinking i might've undertightened or over tightened too now that i think about it as i didn't use a torque wrench

BakedBandit said:

Gotta pressure test w the nitrogen. Your vac pump likely not up to the challenge. Either get a 2 stage pump or Get the micron gauge to see where it gets you.

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you make a good point. as long as i pass the pressure leak test i can hook up any 2 stage vacuum pump and run it for hours and can be confident it got down to at least 500 microns because i dont have a leak right?

MrBungle said:

did you open the valves at the condensing unit?

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yes the valves at the condesnsing unit are all the way open right now.

where was the frost forming on the high side? near the indoor unit or the outdoor unit? its odd that the high side is frosting up and not the low side.. makes me think there might be a restriction probably at the metering device Do you have access you refrigerant gauges?

Does the pioneer offer any sort of built in diagnostics in the form of light flashes/beeps at the indoor unit?

I have been running daikins for years now and they will throw a code with beeps and light flashes if the coolant is low.

I didn't use the micron gauge, just ran pump for like 2 hours. Doing the nitrogen test first should help make it so no moisture is in the lines and that will help the vac pump do its job better. If there is moisturenin the lines it can take forever as it boils and freezes.

MrBungle said:

where was the frost forming on the high side? near the indoor unit or the outdoor unit? its odd that the high side is frosting up and not the low side.. makes me think there might be a restriction probably at the metering device Do you have access you refrigerant gauges?

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the frost was forming near the indoor unit. The frost starts about two inches before the indoor high side flare nut and ends at about two inches AFTER the indoor high side flare nut.

Does this indicate a possible restriction where the frost is at? Or is it still possible to have a restriction at the metering device and still see frost where i saw it?

the metering device is the tee that my service port is a part of, correct?

is there a way to confirm whether the metering device has a restriction or not?

the metering device is typically near the indoor unit in the area you are talking about... it sounds like it might be an orifice type metering device? I'm guessing there is no filter drier? any chance for some pics?

MrBungle said:

the metering device is typically near the indoor unit in the area you are talking about... it sounds like it might be an orifice type metering device? I'm guessing there is no filter drier? any chance for some pics?

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heres a picture of the line sets indoor next to the head unit. the frost was building up on the smaller high side about 2 inches before and 2 inches after the flare nut.






In the last picture i show how i have my line sets "unrolled." remember, i bought this ac used and the seller rolled up the line sets and i had to unroll it then bend it to fit my grow room. It is in a snake like "S"because i plan to put a SCROG net there and didnt want the line sets in the way.. does it look like theres likely kinks? i tried to be careful. Should I definitely fork out about a hundred dollars or so for a new line set??

And i still have no clue where the metering device is. Is it behind my AC head unit? I also am not sure about if it has a filter drier or not. Where would that usually be?

newguy41410 said:

And i still have no clue where the metering device is. Is it behind my AC head unit? I also am not sure about if it has a filter drier or not. Where would that usually be?

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The metering device would be inside the condensing unit, so technically both line sets are on the low side. If you did not install a filter/drier it does not have one, and I'm not sure if they are a great idea on a mini split. There isn't a lot of room for error with a mini split, their performance/longevity come from as close to perfect installation as possible.

newguy41410 said:

you make a good point. as long as i pass the pressure leak test i can hook up any 2 stage vacuum pump and run it for hours and can be confident it got down to at least 500 microns because i dont have a leak right?

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You should be shooting for 50 micron, not 500, and it should be able to hold it for at least 15 minutes. If you can't hold 50 micron, there are either leaks or ice crystals.

a filter drier is a good install on any refrigeration device it will protect your metering device if contaminants do get into the system some how, tho with these quick install line sets you may have a point.... and the metering device is on the inside near the evap coil.... its the part that creates a pressure drop on the refrigerant as it enters the evaporator to remove heat from the air that passes over the outside of the coil...

I don't see a filter drier on that set up.....and the metering device is probably inside the indoor unit near where the liquid line separates into capillary lines....

I don't know how much time passed between the tear down and the reinstall... how did the tech recover the refrigerant? did he pump it down into the condenser? or use a separate machine and a tank?

I'm not ruling out a lost charge.. I'd just like to know more..... did you mix up some dish soap and water and spray the connections? are there any spots around your connections with oil build up? like on the wall or around the flare nut?

have you tried running it at all since?

good luck pulling down to 50 microns... fucking POE oil has a vapor pressure higher than that at vacuum.

could probably hit 50 microns if you piled dry ice all around the compressor and reciever and evaporator. but thats about it.

there is no point to pulling a vacuum that deep.

what most manufacturers want is 300-500 microns after valving off the pump and waiting a minute or less.

queequeg152 said:

good luck pulling down to 50 microns... fucking POE oil has a vapor pressure higher than that at vacuum.

could probably hit 50 microns if you piled dry ice all around the compressor and reciever and evaporator. but thats about it.

there is no point to pulling a vacuum that deep.

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I've only installed one new LG system, since I bought the micron gauge. From what you say, I'm thinking I might have over killed it. I know I had a bitch of a time getting it below 100 microns. I had to do away with the manifold gauge, and then even had to do away with the rubber hoses. I ended up using copper tubing with a tee to hook the micron gauge to. I'm actually glad to know that I was that far overkill. Like I said, I'm not a pro, and don't do this sort of work for money. I was just trying to do the best possible install for a friend of mine, and didn't mind wasting a couple days to assure that the system was installed the best that it could possibly be installed. Yes, 50 micron is probably beyond reality for a used system, I managed to hit 50 and hold 90, with a lot of work and a nice new dual stage vac pump with new oil.

MrBungle said:

a filter drier is a good install on any refrigeration device it will protect your metering device if contaminants do get into the system some how

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I have seen some heat pump models that will not deal with a filter/drier properly, and can cause some real havoc.

MrBungle said:

and the metering device is probably inside the indoor unit near where the liquid line separates into capillary lines....?

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No.

The metering device will not be inside.
The metering device will not be a cap tube system (not for cooling anyway.)

I don't know what exact model you have, but you can easily find the schematics for it with a simple google search. https://www.highseer.com/pdf/WYC_SM.pdf Here is an example, that should be close.

thanks I see now... and I did a lil more googling.. if you have a pioneer WYE series.... there should be a trouble code on the display with a letter and number

MrBungle said:

a filter drier is a good install on any refrigeration device it will protect your metering device if contaminants do get into the system some how, tho with these quick install line sets you may have a point.... and the metering device is on the inside near the evap coil.... its the part that creates a pressure drop on the refrigerant as it enters the evaporator to remove heat from the air that passes over the outside of the coil...

I don't see a filter drier on that set up.....and the metering device is probably inside the indoor unit near where the liquid line separates into capillary lines....

I don't know how much time passed between the tear down and the reinstall... how did the tech recover the refrigerant? did he pump it down into the condenser? or use a separate machine and a tank?

I'm not ruling out a lost charge.. I'd just like to know more..... did you mix up some dish soap and water and spray the connections? are there any spots around your connections with oil build up? like on the wall or around the flare nut?

have you tried running it at all since?

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About two weeks elapsed between the tear down and the reinstall. The tech recovered the refrigerant by pumping it down into the condenser. No i did not use dish soap and spray the connections. I plan to do so when i get the nitrogen pressure regulator so i can pressurize the system to test for leaks. Unless I should do so now? I think there was oil build up on the one flare nut on the high side that was frosting up. I wiped everything down to see if oil would come back out and i havent seen any oil come back out.

OldPhart said:

I don't know what exact model you have, but you can easily find the schematics for it with a simple google search. https://www.highseer.com/pdf/WYC_SM.pdf Here is an example, that should be close.

Click to expand...

MrBungle said:

thanks I see now... and I did a lil more googling.. if you have a pioneer WYE series.... there should be a trouble code on the display with a letter and number

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Just tried powering on the AC again. No error codes still. High side line isn't even getting frosty anymore but is getting a little cold. Cold enough to "sweat" condensation but not frost. Blowing out ambient air. No refrigerant whatsoever i think?


I took the panel off the indoor unit to see if there is a way to enter diagnostic mode to show me trouble codes. No diagnostic mode apparently. Am I suppose to run it until a code pops up?? Im afraid of ruining condenser by running without refrigerant. Should I just let it run until a code pops up or can this stress out the condensing unit??

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?

on new ACR copper you could probably get below 100 microns easily, but only if you valve off the condensing unit and evacuate the line set only.

the difference between 500 and 100 microns is negligible with respect to water vapor.

regarding filter/dryers.

keep in mind most of these systems put the EEV inside the condensing unit. i think some of the multihead units do not.... but some do.

with the EEV on the inside of the microscopic condensing unit, its unlikely you will find anywhere to isntall a filter dryer owing to how cramped the space is.

also i think some minisplit manufacturers use PVE oil which does not cooperate with filter dryers but will tolerate more moisture than POE oil.