Recharging your home air conditioning unit is a common issue that can be resolved with the right tools and knowledge. To recharge your AC system, follow these steps:
- Turn off the AC unit and ensure it is completely powered off before starting the recharge process.
- If your electricity bill is soaring, water is leaking from your AC system, or your unit is blowing hot air instead of cold, your system may need to be recharged.
- Measure the temperature of window AC airflow, measure the room temperature, and calculate the temperature difference window AC is still capable of.
- Locate the service valves, connect the refrigerant canister, and slowly add the refrigerant while monitoring pressure levels.
Refrigerant (commonly called Freon) is in a sealed system and will only get low if there is a leak. Turn on the AC and let it run for at least 15 minutes, then connect the supply hose from your manifold to the refrigerant container.
To recharge your air conditioner, follow these three simple methods:
- Inspect the unit, purchase necessary supplies, turn off your system, protect yourself, and plug the canister.
- Clean the condenser coils outside, shut off the AC unit, and spray them clean. Allow them to dry for an hour to ensure proper functioning.\n3
Adding refrigerant to your air conditioner should only be done if the temperature outside is at least 55°F. The average retail price of refrigerant is $67 per pound, and most units require up to 10 pounds, so your A/C recharge costs could be up to $670.
📹 10 Min. ReCharge MrCool DIY
📹 How to charge mini split yourself, DIY 410a refrigerant, save money!
REMEMBER TO PURGE THE LINES! I started to film right after purging the lines, but just reminding you to get the air out of the …
Worked on my unit a 12K btu single head senville. Not sure where or what leak was, but started to produce heat like it should. Took whole bottle. I checked pressure on unit after charging and it was right where it should be. Will see how long unit continues to run and recomment if need be. Fittings at compressor were all good, no leaks. Did not check flares and connections from the head unit connections with the line set. If it looses charge will take apart cover and insulation and check for leaks. Unit was originally pressure tested and nitrogen purged when installed. Fittings were all good. If it leaks again might be coil in head or compressor unit. Hope sealant did it’s job. Set to 85 F and unit was putting out 109+ degrees, when set to 70F put out around 88 degrees.
Hello Brian, This is a great article. I am getting ready to order your kit. I have a Mr Cool multi zone with 4 line sets. Are each of the zones closed loops unto themselves? Each line has a service port. I suppose I should connect the recharge unit to whatever zone line that is deficient. Mr Cool was reluctant to give me information about how charge the system. Thank You.
Great article! I had no experience with mini-splits, but just bought a house filled with them. One of our units was not working prior to moving in, and of course it’s in the room that’s 75% windows and in Texas and in the summer. I watched this article and did a decent amount of research, and decided it was worth it to risk the price of the kit even if it wasn’t the solution. When the kit showed up I quickly learned my pipe configuration was different than the article. I sent a couple of pics in an email and Brian responded almost immediately, and within 10 minutes I had cold air blowing! The kit barely costs more than many techs will charge just for diagnostics. I could not be happier that I stumbled across this article. Thanks, Brian!!!
This kit works! I admit I was a bit skeptical whether it would fix the low refrigerant problem in my Mitsubishi mini split. I’m happy to say that I had zero problems using the recharging kit and my air temperature went from 61 degrees to 49 degrees. Anyone that’s even a bit “handy” can use this kit without issues. Thank you Mr. Niskala for this article and your money saving kit!!
Mine was blowing room temperature air in heat mode so I got this and tried it. I think I only added a little bit because the needle didn’t really move much, but it made a difference and now it’s blowing warmer air. Maybe it needs a little more, I’m not sure. The needle is in the middle of the blue zone. Who knows how accurate that gauge is?
Just curious. AC systems are sealed and should not leak. Once they leak, you have to find the leak and fix it before charging the system again. Otherwise you will just be recharging in a month or so. Can you tell us what happened before, and what you did to fix the issue with the Mr Cool unit? I am thinking about buying one in the future, and want to know what kind of expected lifetime the units will have.
Will this work on a Mr 4 zone? One of my Zones makes a strange noise everytime the compressor kicks in, the air handler makes a ocean wave sound that last about a minute. It cools the room and all but I’m afraid I might have a leak somewhere or I might be low on refrigerant. Mr cool is well known for shipping the pre charged lines empty I have heard. Will this help.
I have the Mr Cool DIY 12,000 unit. Initially had a bad circuit board replaced then the unit would not switch to heating mode. I have received a new outside condensor unit under warranty and want to make sure I’m doing it correctly. Should I be able to just close the valves on the current outside unit, remove the lineset connections, and then reattach them once the new unit is set and be good to go? I’m wondering if there is a potential for there to be too much charge/refrigerant with hooking a new outside unit to the existing lineset and inside handler unit being that the unit has already been opened and operated? Or am I thinking backwards and I’ll have low charge/refrigerant? I’d like to order the recharge kit and have it on hand before I do the swap if that’s what I’ll need. TIA
Hi Brian, I bought a kit early in 2024, as my 5 year old mr cool 18k wasnt heating or cooling anymore.. The kit worked great. and has been working well. just today the indoor unit was frozen up solid. I let it thaw out, and it is running again. I just used the gauge that came with the kit, and found that my coolant had dropped below the blue zone and into the top of the yellow. So my question is, can I order just the canister of R410a without the gauge? If yes then how would I do that? Thanks, Dan
Brian, thanks for posting this! I just replaced my AC compressor in my car and recharge the system from empty vacuum state to blowing ice cold air here in Houston Texas in 140° heat. Then it occurred to me that the Mr Kool in my garage might be the same process. Your article basically confirmed that including the same R410A. Since this article is 3 years old, I am curious if the system is still holding up even with these recharges? On my vehicle I found that the only source of leaking was the actual Schrader valve where the connection is made with the can. Most vehicle ACs that leak can be tracked down to that Schrader valve. Have you ever vacuumed the entire system down and done a leak check? If so that would be an awesome article to show how that equipment connects if you are aware?
Thank so much for this article! I have a fugitsu unit that was installed seven years ago. I’m getting an A1 code. (about once every other week or so) Everything I can find on the internet points to a low charge. So I think this kit is perfect. Is your Kit pre-blended with with UV Dye & Leak Sealant? And how important is that?
hello from romania,i want to know what means AC mode? i have a daikin ac system and i want to recharge with r410a but now the outside temperature is low,about 8-9-10 celsius degrees so,can i load now?the system can works in heat mode or he must works in cool mode -i have cool mode,heat mode,auto mode,dry mode,and fan mode,so what is ac mode?is a cool mode??
This is an awesome article thank you so showing us! Question: I didn’t have any leaks when I hooked up my 18K Mr. Cool, but I”m wondering how full they really ship them since it’s a DIY. I’m interested to see if it’s just slightly low and a little add of freon would make it even better of an AC unit. It cools nicely now, but if you hit about 110 degrees outside and the garage starts to get hot it does struggle a bit. I do have to admit, this is one nice unit Mr. Cool sells. Anyway, what do you think about adding a little to just a normal DIY install to get the maximum cooling effect?
Brian great article. I just installed a Mr. Cool 4th Gen multi zone mini split. The instant I turned the unit on it showed a PC 03 error. I don’t think the condenser ever kicked on. I reached out to Mr. Cool tech and they think the unit must have been shipped without coolant. They are sending me a your kit to charge. Will your kit work to fill the full condenser? Will I need to vacuum out the system? Does the condenser need to be running while filling?
I purchased your kit this Monday, received in TWO days….thank you!! The gauge on my unit was barely registering when hooked up to my Mr Cool unit and it took the whole can of R410A to reach approximately 60 to 70lbs. Is this common? Also, my charge port was on the lower refrigerant line….I have a 120 volt unit. This may be useful to your subscribers to be aware of. It was the only refrigerant line with a charge port. I just ordered another can to top it off from your website. Thanks again!
thanks for the article. I screwed up when I installed the mini split and didn’t get the lines vacuumed before I released the refigerant. the mini split worked for about 2 weeks and now it’s making a clanking sound on the outside unit. I’d like to get the mini split working. I was thinking I would need to vacuum out the lines correctly this time and then add refigerant. Does that make sense? If I hook up the vacuum correctly this time, will it just suck out the refigerant? Is one of these bottles enough to fully charge a mini split? Thanks in advance.
I have a Samsung split unit. It will on for 15 minute then stop, but when it on there is no cold air coming out just like regular air. I was wondering if it low on refrigerant? I checked the light sensor on the outside unit it said I PM OVER CURRENT. I read the manual and one the solution is to check the refrigerant level. Do you think adding refrigerant will fix this issues?
This kit was a life saver! Brian was so quick to email back and the article was perfect for a step-by-step guide. I actually used this on my camper’s unit which did have a refill port. Mine did not require the adapter, but I had everything I needed. It was easy to do and I plan to buy another kit to recharge my Mitsubishi split unit! 10/10 recommend. Last week’s camping trip was nice and cool!
Thanks Brian. Great article!! I am installing a Mitsubishi mini split but because of line lengths I may have to add more refrigerent. Just a couple of questions before I purchase. What do the dial colors mean. Are they pressure? Also I dont want the dye. Can I get a kit without it? Thanks for your help. Derrick Willmott
Everything about my Mr Cool looks exactly like yours, except for the line connecting the adapter to. My unit connections into the side are reversed to yours. The connection for connecting the R410 can is on top, just the reverse position of yours. Is it possible my unit is hooked up incorrectly? I purchased one of your recharge kits but do not want to use it until I am sure the connections are correct. Thanks, Dan
Can I do this with 134A in like this using a car charger can and single gage ? I have adapters that will allow me to to connect to my AC but I have not seen any other vids saying this can work? You seem to be the only person using them, and I can buy the car kit for a much cheaper price by pound of 134A . Automotive cans are about 50 bucks for 2pounds, with a commercial can it’s 175 a pound plus gage kit !!!! I am not able to afford the cost of commercial help or supplies
Does it matter what the temp is outside when using the gauge? It’s a little warmer today so I hooked the gauge up again and it was showing blue but close to the yellow. I gave it a couple squirts anyway so now it’s basically on the border of blue and yellow. I set it back to heat mode and let it run for a while and now it’s blowing warm air at about 90 degrees. But I have an identical unit that’s newer and that one is putting out more like 125 degrees in heat mode right now. Is there anything else I could check?
I installed a 12k DIY mini. When I went to tunr it on. I heard a spraying sound outside and saw a plum of white smoke. I realized i for got to unscrew out the hex key screws that opens the passage way. Does this mean its totaled? just needs recharged? or possible i ruptured the line at a weak spot? are there remedies to fixing this?
Hey, while installing my mr cool 24k, I kinked one of the lines and it had an obvious leak of refrigerant. It probably leaked for about 10 minutes before I closed the condenser with the Allen key, and then disconnected the broken line from my other line, I will be replacing that broken line, do I have to vacuum? And will this bottle be enough for me to recharge to proper level? I don’t think all of it leaked. Probably a good amount. Will this gauge still give me to a proper reading for my 24k? Or is this only accurate for 18k
So while installing a dual zone 18000 BTU Mrcool, I didn’t tighten a connector well enough. Didn’t show up on the initial soap test, but it lost compression over the next week (which I did not notice since it wasn’t cold/hot enough to run the heat or AC). I found the problem, so now I need to recharge the system. The question: if the system has lost essentially all coolant, will this be enough to recharge it, and will it work?
Will this recharge kit that you have for the Mr Cool AC units work if you have to relocate the AC system and I’ve got the Mr Cool 12,000 BTU in my camper but the camper is being removed and I’m taking the Mr Cool AC unit out of it and putting it into another one. I didn’t know if I’d have to evacuate the lines or what but then I’ve heard that you can’t do it cuz I don’t have something to do I do have a pump but I don’t have anything else
Update: Seems like it was a success! But, you need to update the instructions with the new gauge provided to look at the outer ring for R410 freon. I literally was looking at the wrong Blue. So I put the can back on and it literally took the whole can to get to the middle of the correct blue, where it belongs. And that triggered a much better compression sound. Nice. And no more EC error. BUT, one has to ask, where did ALL the freon go? Why would it take a full can? Doesn’t that imply there is a leak somewhere?
Brian, where can i get this kit. My unit was iced up outside and starting inside. Sprayed a little soap on it and i saw tiny bubbles. Tightened up a little and it stopped. Is it common for it to leak a little going from hot to cold? Its been in for 2 years and i havent had an issue. And there were no leaks at install.
I have two of these Mr Cool DIY units. A 24k in a shop/garage and a 18k in a bedroom. I noticed the 24k occasionally ices up on the suction line but the second I shut it off thaws out almost instantly. Does that mean it’s low on refrigerant a bit? I’m in east Texas and it’s been over a 100’f lately. Have the thermostat set to about 72 and when it gets to the middle of the day the suction line turns white. But literally thaws out the second I hit turn off on my wifi on my phone.
Brian, today I recharged my mrcool 9k. Previously when i was installing it i did not tight enough the pipe connectors it worked for the evening and started to blow warm air. Today i charged it and it started to work but i noticed that the small pipe is not getting hot during cool mode period. Also it was working for the whole day and when I came in late at night it started to blow warm air again. Any ideas Brian? I bought just now a kit from you. Do you open both valve on the unit during the charge?
Brian, What have you heard about R410A refrigerant being phased out on January 2023? Will 410A continue to be available and will it become exorbitantly expensive like R22? Do you know if there an alternate refrigerant that will work in MR COOL units? I understand that R410A has a short shelf life of 1 year which means we can’t really stock up in anticipation of future recharging. Thanks, Ron
Hi Brian, Checked the pressure on my unit (mrcool) and seems to be ok (upper limit on green) The unit blows 72 deg in the house, but temp outside on the pipe that goes into the outside unit is around 45-50. I assume the compressor works but somehow it does not let the coolant to go to the inside unit. Any thoughts, please? Sorin
this is the second part of what you need to do: – this is what I do: – First, if you are low, that means you have a leak.. in my experience, it’s that the fittings come loose after years of vibration… so before you do anything, turn the unit off – and re-tighten the fittings there are the two lines… use 2 wrenches… then I would use a vacuum pump on the system because if there is a leak, there will be some air in the system, and you don’t want that. – once your gauge shows -20 for 30 mins (it means it’s holding vacuum) then you know you have no leak, and can NOW recharge your system…. NOW you can turn the system on full cool and lowest temp it will go… fully empty it will take about 1/2 a container – like the one he shows… I didn’t do the open close – I just opened it up a little bit and close it when you are at like 90 psi, and then do the open close 🙂 – BTW there is no High Side access on these which is not great – there really should be… but like the OP said, just take your time.
So I did use your method of adding refrigerant on another mini split I have, after running it on cool and seeing that the pressure was down to 100 and thinking it was maybe not as cool as it should be. I brought it up to 120 as per your on off method. I left the guage on to monitor it as it seemed like it took quite a bit of refrigerant. I noticed that when off it was up to 250 pounds pressure, then I turned it on and it dropped back to 120. Later I checked it and it was again up around 250 and so I turned on the calling for cold and it dropped to 150. Then I turned it off completely again (to try the same test as before) and I noticed the fan kicked on even while it was off (for a minute) Then I turned it back on, full cold, and it did drop to 120 pounds. But I also decided check how much I had put in by weighing it (the weight of my bittle subtracted from its last measurement of 112oz, after I had weighed in 40 oz to another mini split that was completely empty) and I must have put in about 35oz.. and I now see the total capacity is only 30oz ! I had release a little out in the interim while it was off for fear of having over presureized it. My conclusion is that when the unit is off or not drawing, the pressure goes up. Once it is back on, it drops to the 120 sweet spot. But it seems trange that I could add that much refrigerant and what if it was too much? I will continue to monitor the guage. Thank you!
Great article 👍 My multizone minisplit lost most of its 410A. Repaired the leak and will fully evacuate what may be left in the entire system including the compressor. Pressure test with nitrogen/ then vacuum down to 200 microns and hold/ once that is done, I will add just under 6 pou ds of fresh 410A via one of the line sets. Question: Do the king valves (these are not the line set service valves but are at the top of the multiple zone manifold) need to be closed and then opened only after the line sets have taken the 6 pounds or are the to be open while adding? Not sure if the two line sets (less than 50’) can hold all the 410A. At what point is the system turned on? I dont think it should be running while initially no 410 is in the lines.
Hello Sir, My mini split system was leaking and lost all its freon. Now I need to recharge it to full capacity. The outdoor unit comes with 2.82 lbs of refrigerant, which includes a 15-foot line set. Should I buy a refrigerant weighing scale to recharge the system, or can I follow your method that uses PSI readings around 117–120?
I have very little gas in my unit and it requires 44 oz of 410A. The pipe run from the outside unit to the handler is approximately 11′ and I’m wondering if I should just buy the scale to make sure I get exactly 44 oz in the unit. Do you think it is wise to take this route or the one you have outlined in the article? Thanks.
question, when your releasing the freon in increments..the 2 valves on the condenser..should they be open or close?..if you can please clarify.i appreciated. am just confused, because when your doing a vacuum to your system to make sure there ar no leaks, your suppose to have the valves closed, and then after open the 2nd valve for 5 seconds and close it again, and then remove the vacuum, and then you open both valves again..so for charging the unit, do they have to be open or close…thanks
I found pressure to be really unreliable on a mini split, especially if it’s something with an electronic expansion valve, as they will adjust both the subcooling and superheat on the fly for optimal condition… Mine doesn’t have electronic expansion valves, just capillary tubes, but I did it by pressure and feels like I might have overcharged it, as the compressor started becoming harder and harder to start, and dropping the charge (recovering refrigerants) fixed it. When this is done, the AC is cooling better but also the compressor hard start problem disappeared. However on the R22 system the pressure is reading to around 40 psi (which corresponds to a saturation temperature of about -10C), and it would never go above that, but any attempt to try and go over that either resulted in weakening the compressor or even seizing it up. I think saturation temperature adjusts itself based on various operating conditions as well as fan speed (you really want a ton of airflow over the evaporator to get accurate reading). If you look inside a mini split condenser there’s a capillary tube leading from the condenser coil before it comes out to the valves. I do not know why this exists but there is likely a reason for it. This does not exist in standard AC units with a TXV. I know some even do it by current draw, but again, it seems unreliable. Weight seems to be the most accurate way to do it. It feels like a mini split needs to be completely recovered and then have the charge weighted out.
Thank you so much for sharing the instruction. I am trying to do the top up of R410a myself too. I have gone through quite a number of articles in Youtube and I have learned that at 120 psig (according to the PT Chart) the temperature of the gas at the evaporator should be around 41°F but your digital temperature gauge at the evaporator air outlet was showing 26°F. Have I missed out something? Hope you can help clear this up for me.
Where can I buy a new port that you fill the unit through? It is that brass fitting attached to the AC unit. Mine has an extremely small leak under that large cap next to where you are filling in the article I found the leak with an infrared detector, very small but it does leak! Thanks if you can help! JIM
Thank you for the refrigerant link. I will have all the supplies I need to get this done. QUESTION: When beginning to add the refrigerant, should both high and low pressure valves on the outside unit of the mini split be wide open? What about when doing a back pressure test with Nitrogen. Are they open or closed? I don’t want to mess up the compressor or anything by accidentally shooting nitrogen in there if its not supposed to be. Thank you for all your help. Watched the ads for your websites ad revenue. Will be perusal more of your mini split electrical wiring articles tomorrow.
Hey guys. God bless all. I hope someone can help me. I have a blue ridge mini split multi zone, last year works fine, but now is not cooling, there’s not errors displayed in the indoor unit and not freezing pipes into the outside unit, i still think must be something with refrigerant load. Any idea how to fine a refrigerat load using the gauge.? I know for a single zone is about 117 to 125 psi. Is the same for a 4 zone minisplit? Thanks for any help. God bless America
I could use some help with an issue I have. I have a Blueridge mini split that has a leak it’s been dead for about 2 months now. What would be the best way locate the leak and since it’s not been working for 2 months I’m sure all the R410a has run dry so would I need to refill the unit in order to find the leak? What would you recommend doing?
I connected the hoses to charge my Mitsubishi mini split and it looks like it has 150 psi. Does this mean it is overcharged and I need to remove some of the 410a to get to the 120 psi? The unit is running in cooling mode and the temp outside is 75 and 90% humidity. What is the best way to get it to the sweet spot 117-120 psi? Thanks
Thank you so much for your article I tried it on my Senville two air handler mini split. Aura model 18000btu. It worked like a charm but only after the third try. I must stress to everyone please bleed the lines. Make sure the air conditioner is running when you’re hitting this psi Mark. Again bleed the lines, bleed the lines on the gauges. If you ever have trouble DM me. I can explain to you in detail what I did. I don’t make YouTube articles much at all. My leaks were s result of loose connections. All my refrigerant leaked out so I charged it from empty. Lord bless.
Is your AC running while you are adding this refrigerant? I have seen other articles where they weren’t running and brought the pressure up to 250, then it dropped to 120ish when they started the compressor. (You thought I was starting a dad-joke there didn’t you, well then: it must be hard to catch your AC when it’s running 😆)
Just had a mini split charged with what the guy said was 2 lbs 4 oz of r410a. Prior to the charge the suction line was occasionally freezing if it had been running long enough but it was still throwing air out at 43’f which sounds like 10 degrees hotter than your article says at the end. Now that he added 2 lbs oz the coldest the air coming out is 49-53’f. If he added it while there was ice or something could it have read low on the pressure and then later when stabilized the pressure is now too high causing that 53’f air coming out? Thanks in advance!
I just completed my first mini-split install. BUT it failed! Perfect vacuum pulled (verified 24 hours of holding at -30mmhg). After I introduced the refrigerant, no leaks/perfect. The problem was when I removed my blue hose from the low side connection….it blew refrigerant all over me while unscrewing it and pressure went down to zero! I used the connector/adapter that came with my gauge kit….I think this was the problem. The charging port adapter for vacuum service that I bought has a schrader valve on the one end (green gasket on the connection side) but the one I USED did not have this schrader valve (I thought it did). Quite certain this was my problem. Please help/confirm. I now have to get an HVAC tech in to recharge my system. Any idea how much r410a would have come out? All of it (120 oz) or just a few oz??? Thanks in advance.
When my main living room indoor unit is on In cooling mode it cools off awesome. Approx 1000 sq feet room. But when all 4 units are on it doesn’t cool as effectively and struggles to get to set temp. The other units cool though. Also for the bedroom units to cool really well the main one has to be on and cooling…. What’s up with my unit?? It’s a 4 zone Trane 20 seer I believe.
Thank you for for sharing . The best practice for mini split is to start from zero … Pull the vacuum and add refrigerant by weight. Anyway, I also top up my 9000 BTU gree inverter.. During topping up, I keep monitoring psi on the gauge, current from the clamp meter, temperature on suction line, temperature from supply vs return air on evap unit. I turn my ac to turbo mode or max cool… run for a while …and adding refrigerant… My sweet spot Gauge psi.. 125-130 Current getting close to RLA (it is ok for mini split to ramp up to RLA on turbo mode… We are not gonna keep using turbo mode all the time in real life, right?… The current will go down when on normal operation. Super-Heat keeps fluctuating in the range of 5 +-3, which is normal Delta T or return air temp minus supply air temp on the evap indoor unit is between 15-20 degreeF
I am grateful for these articles. I’m a widow in N.Ca. and the contractors are constantly trying to gouge me. For a single ductless minisplit (21-24seer 18-21 btu) unit I’ve been quoted 6000-10,000. Costco has a mrcool 21seer/18but for $1,500 now I need to get a friend to help me install. I already had the electrician (his bid for a lot of work was 3.8K where most bids are at 7-10K for electrical work) install the 240/40amp circuit & outlet.
Failed recharge. sigh. I recently installed a new Senville 18K btu unit. Did a 1.5 hr vacuum test, no problem. Finished setup and started the system running. (note: It’s winter!) It started heating just fine. Then I got a call and had to leave for six hours. Came back – and it wasn’t heating anymore. Turned it off, and checked the Freon pressure. it was 0. Apparently the system developed a nasty leak somewhere. Since I had shortened the lineset (I only need about 20′), I assumed my flaring job wasn’t good enough. Due to shipping snafus, I had a spare lineset (25′), so I just replaced my shortened one with a factory built one (and looped it). Since I had to wait for the Freon to arrive, I did a VERY LONG (4 day) vacuum test. It held vacuum. It’s 36 deg F outside. Since there was no freon and I didn’t want to run the compressor when empty, I did a slow fill to 100psi. Then powered up the system, and was able to fill it to 115psi. Wouldn’t go higher. (freon too cold??) Yes, it’s in Cooling mode – as I do have an alternate heat source in the house. Let it run for 15 minutes – no cooling, blower running inside, the fan on the outside unit is NOT running, but I can hear the compressor running. Pressure hasn’t changed. Tried flipping it to Heat mode, and waited 15 minutes. No heating inside, inside blower running, outside fan and compressor running. No heat. Pressure hasn’t changed. Gave up and shut it all down. Any suggestions?
My mini split came with 16 ft of lineset. I remove 8 ft. The system was already low from a leak. I used the self recovery system for unit and disconnected lines to shorten. I re flared everything and placed flare seals and nylog on all connections. I vacuumed system down to -30 and it held vacuum for an hour with no change. I released 410a back into the system per manual. Based on outdoor temp and calculated indoor wet bulb temp my target super heat was like 15-20 degrees. According to my psig saturation temp chart my PSI should be at about 116 psi. I slowly added refrigerant over 30 min until I reached 115. Once I reached 115 the gauge started rapidly increasing to unreadable >350 psi. Im worried I overcharged it but how if I was following the chart? Any help would be appreciated. Indoor unit is now icing up.
Great vid! Hey No one has a article on removing part of the charge on a minisplit that has shorter lines than the built in charge was designed for. Can you please do one? I feel like it’s just release the full charge into the lines, start the system, and slowly recover via the suction side of your manifold into a recovery tank while monitoring the scale until you reach the weight that matches the pre-charged weight minus the final weight your line length requires. Is that correct?
I really appreciate your articles, I have several mini splits that I have to charge and if you could help me clarify a few things I would be most thankful. I have several Idea air mini split ac/heat pumps to move, one 3 ton still blowing nice and cold and heats, one 2 ton that cools and heats but not like it used to, and a 1 ton that no longer heats or cools. I’ve watched your article on how to check the pressure and the other on recharging, these units have quick connect fittings so I dont think I can use the nylon sealant. My question is could you suggest a procedure on moving them, i.e am I to just close the line valves, disconnect the quick connect hoses, transport and reconnect everything, reopen the valves, puge air from hoses then follow your 2 articles, or am I missing some steps? Thank you in advance…..
Great articles, thank you. Question: I have fujitsu flex dual zone with an AOU18RLXFZH outdoor unit, are the ideal low side pressures the same 117-120 with both evaporators running indoors? Just had a big snow storm up here in CT so it will be a while before I can run it in AC, but the system has had that water running sound along with gassing sounds after cycling off. Fwiw, its been doing that since I sucked it down, released the precharge and started using it last summer. No leaks according to nitrogen test or electronic leak detector since then.
Thank you Thank you Thank you Following your steps i was able to fill my system I have 2 zones I hook up the gauge to the 1/4 inch pipe like you said and I was scare at first because when I hook up the gauge it was at 50 but when put it on cool and turn on the system it will drop too zero It didn’t exactly match your article but I knew I didn’t have a leak because I pressure test the system and ran a vacuum before So I just said fuk it and follow your article it was on cool and the system was running the gauge was at zero but as I put gas in the gauge will go up little by little until the gauge read 115-117 sweet spot Also I went to each unit and the air went from just cool air too actually cold air I think in your article the system probably had more gas then my system or maybe because my system is 2 zones that why its started at 0 when I ran it Thank you, I really appreciate the help, gonna check to see if you have a donate page like with PayPal want to send you $50 tip for your help bro
You seem like the guy to ask after perusal your articles! I installed a dual zone system myself but had an HVAC Tech make the final connections and vacuum the system. He shortened one of the linesets by about a foot, and the other by about 4.5ft. Can this method be used to check to see if it’s overcharged? The unit comes pre-charged for two linesets 16ft in length. The reason I ask is my unit seems to be a little louder sounding than I expected as I hear others say it’s pretty quiet, and sometimes I feel it’s output could be a little better. Mine sounds like a vacuum when it pumps to the indoor heads, though it is also up on the wall above a walkway in between the neighbor’s house, so I’m not sure if thats what’s making it sound louder. Are you able to advise whether the vacuum sound is normal? It’s not a suction sound but it sounds like a vacuum motor which I presume is the compressor. If I do need to remove refrigerant do you have any advice? I’d rather not call the same guy back as I don’t think he knew what he was doing, and I’ve been having a hard time finding any company that wants to touch it since they didn’t install it.
The a/c was working, not the heat, I turned the a/c on to fill, I had frost on the line. It showed 50, I filled it, I couldn’t fill it past 110. I went inside, the heat worked, when I went outside with the heat on, it was pegged at about 220. I went back in and tried to get the a/c on, it wouldn’t go on, but it is 61 inside and 62 was the lowest the unit would go, so I shut it off. When I went outside, the gauges showed 200. I am assuming it okay, if you have any suggestions, let me know. I can imagine hooking it back up and turning the a/c on to verify pressure. We have 2 ductless heaters and a pellet stove, so we’ll be okay.
Let me start by saying…Love your articles. Very helpful. I have a dual zone mini split and one of the zones is low on pressure.The other one is fine. Can I still run the one that is fine until I get the other one back up to pressure. Also when I go to get 410a refrigerant it ask about e.p.a cert or am I going to sell to someone with e.p.a. cert. do i just say I’m going to resell. Also I’m in California. Does that matter? Thank you for your time. The link doesn’t take me to the tank that you had in the article. Will I need a adapter for the 7.5 lb or the 11lb tank?
Thanks for the tutorial! The AC guy told me that the freon is 1-2 lbs lower than normal two weeks ago. I followed your instruction and made sure all the hoses were securely connected. However, the gauge shows a low side pressure of 0 (the AC is running fine). But it stayed at 210 psi when I release the refrigerant into the unit (is it the tank’s pressure?) Do I need to open the service value to get the pressure readings?
Purging…….. On the yellow hose, 1-connect to tank, and gauges. Slowly open the valve on the REFRIGERANT tank as to slowly release some refrigerant 2-On the gauges, slowly unscrew yellow hose at manifold until you hear air out, should just take a second. Quickly tighten. On the blue (suction) hose, 1-Fully tighten hose on the HVAC unit, and on the gauges. 2-Slowly loosen connection on manifold, the remnants of air in the line will bleed out at the connection to the gauges, (you will hear the sound of air coming out) at the manifold connection, and you can quickly tighten immediately after. It is a split second thing!
Hi, I installed a new 2 zone Lg Mini Split. Getting error code 35 for low pressure after running for a few minutes. I Hooked up the gauges and added only a little 410a. When the fan is running the pressure is at 120 and when the fan stops the pressure is at 68. I’m still getting the CH 35 error code for low pressure when running the unit. The pressure doesn’t seem to be changing. Any advice? Thank you
Hello. I started this profession a couple of months ago. I’ve been doing ac systems but not minisplit. Today I had to check one. The thing was that the system was not cooling and was freezing. I connect everything, blue line to the service valve and and check the pressure of the unit. This is a 410a minisplit. The reading was 50 psi, so I proceed and put some refrigerant in it. The pressure went up to 118 psi. When I turn off the unit, the pressure went up to 250 psi and I waited for 5 min and the pressure was 250 psi. Then I turned on the system again, but the pressure went down to 75 psi…. I don’t understand what happened here. I waited and the pressure was the same. I turned off again….up to 250 psi. The system was not cooling enough and I didn’t want to anything else. The pressure of 250 psi was to high to my knowledge . Did I do anything wrong…..? The compressor was working, the fan…everything. This systems are more electronics than the regular systems…. Appreciate any help. Thanks
Hi for a r410 cylinder or bottle, should i turn it upside down when charging the unit or should it be sitting upright…? Am also intrested on how u actually open n close the valve for charging till it hits 120psi… any tricks or secret? Mean can u show us how u actually did open & close the valve frm 100psi till you reachef 120psi…thnks
Thank you. a great Reference to doing things: I have the gauges adapter and 410A thanks to a friend. i have fujitsu AOU24RML1 4lb. Design pressure High side 450, low side 240 It has two 9KBTU units to one machine? I should add to 240 psi if I am LOW. I’ll look for one with the same machine to help on. appreciate some advice
MAKE SURE YOU WEAR GLOVES….amzn.to/3fxiF1u AND SAFETY GLASSES….. amzn.to/3fuqFjv Remember to purge the yellow line, BEFORE you open the blue valve. So after attaching refrigerant jug, open the valve on the jug. Then press the schrader valve ( the pin that shows on th center of the manifold) with a small screwdriver for a split second, and allow just enough refrigerant out till you hear a split second pssst! We did this just before we started the filming, but did not catch in on the article.
the adapter is unavailable, is there another that you recommend? will this work:amazon.com/Radracing-Female-Swivel-Adapter-Thimble/dp/B0758CYHYL/ref=sr_1_1?dchild=1&keywords=R410A+Straight+Swivel+Adapter%2C+R410A+Mini+Split+Adapter+with+5%2F16%E2%80%99%E2%80%99+SAE+Female+x+1%2F4%E2%80%99%E2%80%99+SAE+Male+Quick+Couplers+Thread%2C+Fits+for+HVAC+Air+Conditioner+Mini+Split+System+-+2+PC&qid=1590721097&s=automotive&sr=1-1
Please bare with me as Im not a HVAC tech. Here goes. I just purchased a LG 22000 btu 1 zone mini split system. The unit comes pre-charged for a 25 foot line set, but I need a 35 foot line set to reach my living room,so I purchased one.. I believe after perusal your 2 articles I would do this…..1) Install the system with the 35 foot line set. 2) Vacuum out the line set down to -30psi, wait a while and check for pressure leaks. If there are no leaks, my next step 3) would be to release the R410A which came pre-charged in the unit into the system. 4) Then I would check the pressure in the line set with the vacuum gauge to see what the psi is and then add as much R410A….. which I would have to purchase separately, to get it to between 117psi and 120psi.. Im pretty sure there is no need to purge the system. Does this procedure sound correct….thanks PS the manual says to add 0.38 oz/ft. So that should be about 3.80 lbs.
I am installing a second-hand 12000BTU mini split, it was working at my parents’ home for the past 2 years. This is the first time I’ve done this. I don’t think it was decommissioned properly as when I attached my gauges there was no vacuum, I vacuumed both compressor & lines together by opening the valve when I vacuumed the lines. I gassed it to 125psi then turned on the evaporator & set it at the lowest temp with the fan on high. However, the compressor kicks in and out & the pressure changes from 240psi when idle, then when running (maybe 30 seconds) it drops as low as 50psi before the compressor goes idle again. What am I getting wrong? Any & all advice is greatly appreciated…
Thank you for the article. My 410a was delivered today and I just got done recharging my 24k BTU Mr Cool. PSI was at 75 and wouldn’t get my garage below 80. It was basically blowing warm air. Turned the AC to 73 and went outside to recharge it. Took about 5 min, As soon as I walked into the garage I could feel the cold air again.. Since I installed the split system myself I had all the tools already. $75 for a bottle of 410a is way better than $500 for a service tech to do it.
Thanks a lot for your article. It is really helpful. I have a R410A refrigerant FUJITSU minisplit with model AOU24RLXFZ. In the label, it said design pressure high side:450psi low side:240 psi. It looks the lower sider PSI is pretty much higher than your normal 120 psi. Currently, my low side pressure is 125 PSI and AC is not cool enough. Does it mean I need to add more refrigerant to achieve 240 PSI on lower side?
How long can you store the refrigerant, if you buy it now and may need it when the AC is needed which would be in a few months from now here in Illinois…..we have 2 mini splits Gree brand, the one is good, no problems the newer model seems to be low on refrigerant at the start up of each summer which will be the third this coming year, we checked for leaks, tighten up the fittings and it’s all good, just never did find where it’s loosing it. It heats fine in the winter though. Luckily we have a friend that an AC guy and he comes by to fill it for about $100 each time, but this would be nice to have handy instead.