Mini Split Book on Our Website- www.acservicetech.com/mini-split-book Mini Split Book on Amazon- amzn.to/3ytHJSs Mini Split Book on TruTech Tools- www.trutechtools.com/BooksGuides Mini Split E-Book on Google- play.google.com/store/books/details?id=HN-iEAAAQBAJ Mini Split E-Book on Apple- books.apple.com/us/book/id6445178399

I think a lot of this is over people's heads, but I appreciate your detail and technical knowledge. Well done!

Finally got it up and running. The only delays we had was because we realized we needed some extra parts (I’ll list that below) kzfaq.infoUgkxihMYiJNXcHdbH-7ihymsLz61l7jVyb5O . So we have a loft where our current hvac just couldn’t seem to keep cool during the summer. We have been using a window unit since we bought this house over 6 years ago (all the houses in this neighborhood were built in the 80’s and majority of the houses built like ours use a window unit). I hate window units because they are just so noisy and the one we had really only cools one side of the loft. I had contemplated upgrading our current HVAC, but with all the rising prices these days, it would take years before saving up enough to do that. With the advice of my father-in-law (used to run an HVAC business), he recommended we get an inverter instead. We thought we bought everything we needed, but there were just a few other parts we didn’t anticipate needing (which is what caused most of our delay). My friend and father-in-law did all the work to get it installed and running and now we have nice cool air circulating nicely throughout the entire loft. It is very quiet and even the outside unit is much quieter than our main HVAC unit. Saved ourselves thousands getting this.

So in other words you can check it but it could mean 100 different things. 😎 I'm back where I was before the video lol.

Graig is best HVAC educator ever you my friend are a GOAT I have learned so much watching your videos -Thank you very much for all you do for your trade, a true gentlemen and scholar ..

I take care of over 300 minisplits here in Florida. this numbers work for me: Indoor blowing between 55 to 60 Outdoor compressor FLA as close to what the name plate says. Superheat between 1 and 5. clean filters, clean coils. low pressure is different between minisplits. The manufacturer can give you the numbers expected based on model, tonnage, indoor and outdoor unit combo, etc don't over think it.

I work in Saudi Arabia, mini splits have been the standard here for well over 10 years. Here we can see ambient temps at a mild 135-140 degrees. When checking a charge it’s not uncommon to see units charged at 2-5 degrees of superheat. Anything higher than that during the summer time and the high pressure sensor will shut the compressor down. Winter time where the temps dip down to 40 degrees we normally are out recovering and charging back to the factory specifications. The units are wonderful but they are very finicky

Great Video. It's nice how you put the temp and gauge together and explained superheat and subcooling. The explanation given was very understandable. Great teacher

Step 1. Understand that the only way to get the correct amount of freon is to start with en empty system as correct super heat numbers cannot be correctly optained. Step 2: hookup recovery machine and recovery tank and remove remaining freon from the minisplit. Step3: with minisplit completely vacuumed out, break the vaccum with exact weight clearly written on the minisplit cover. R410a container must be placed upside-down as to draw liquid, on a scale, zeroed out before proceeding. If the minisplit calls for 91oz, then add Exactly the amount it calls for to a fully vacced out system. Have to charge on mini split in AC mode unless you know how to unplug stuff inside on the control board.if its wintertime just make sure the head is in a warm room with small space heater in front of it.

Very good teaching of mini-split systems, one of the best I have seen, thank you.

This is my favorite ac service video. It's interesting how this unit uses temperature to regulate pressure. In automotive ac we a focused on pressure. What an eye opener

Thanks for the video. I have to admit, I'm a little disappointed in the OEM failure to fully exploit the capabilities of the onboard monitoring/control system. The hardware is capable of supporting additional sensors on a bus which could essentially diagnose everything that can go wrong on the unit. It could easily be enhanced to support monitoring/alerting for accumulator levels (in a deterministic state), line temps/pressures, etc. These units should be able to tell the service tech exactly what needs to be done to restore to factory spec. Failed opportunity on the part of OEMs As an embedded systems/real time process automation engineer, I"m half tempted to buy an additional unit and prototype a retrofit kit. Imagine being a service tech, you arrive on site, and you wirelessly connect to obtain a diagnostic report for the unit. It tells you everything you need to know in seconds. For that matter, the customer could simply email the report to the service company.

Thank you for all your teaching videos. They are making huge difference around the world.

Great video! Thx. I especially like seeing the cut open EEV and the accumulator. The accumulator is a bit of a different design with the input at the top and then 2 internal tubes running to the compressor.

That was great i so appreciate your wonderful knowledge on Mini splits take care

Perfect video! I knew I was not educated enough with these and your comments highlighted what I need to study next. Thanks for pointing me in right direction

Thanks for the great information on mini split pressures. I just bought one and now I will be able to pressure test and charge the system. I love all your videos and am an avid fan of all of them.

Thanks ! Good job ! That cut away of the accumulater is cool along with the metering devices . I'm a fan . Thanks again & again good work !

I really appreciate you putting this video out. Many clients are going this way of the mini split systems. Thanks.

One of the easiest ways to work out a low charge on these inverter units is the low lapour line pressure i agree, another way is to check temperature from indoor supply air in cooling mode and compare to room temp.. basically for r410 and r32 if we dont see atleast 10-15°C (50-60°F) temp drop on the evaporator after atleast 15min operation, then i would start digging further for leaks.

So what I gather from this video is that writing down all this information for future troubleshooting is golden. I'm struggling with a Mini Split right now. After pressure testing the line sets to 400 psi, and then leaving them pressured to 200 psi for 3 days, checking for leaks every day, one flare started to leak after 3 weeks of running. Seriously disappointing. Now I have to have a guy come in, vacuum all of the refrigerant out and re-fill it. Very expensive. I will check out all of your other articles.

Very good video man!!!👏

I would like to see a video on leak repair service on a multizone mini-split. In particular the refrigerant recovery replacement assuming an unknown loss of refrigerant due to the leak. I will assume the leak has been found and fixed with usual procedures. Probably a re-flare. Some questions based on need to charge by weight are: 1: Best way to recover without oil loss? As a vapor? 2. Entire system evacuated since all refrigerant has to be recovered even if repair was to an isolated line. 3: Should recovered refrigerant be reused? If a leak, recovery tank has less than full charge so it may mean careful weight measure and weighing in remaining as virgin. 4. System test of all zones? 5.What else? 6. Perhaps bringing the remaining system up with removed leaking evap. head. as temporary measure while new on order. Great channel, book, and cards. Thank you!! Helped me get 608 universal and refresh on modern methods and tools.

thanks, Craig!!!! awesome presentation as always.

Hi! Acabo de ver que estás subtitulando tus videos al español y t agradezco por ese motivo. Ahora puedo entender al 100% tus videos. Mi inglés es muy básico pero ahora no hay excusas para seguir aprendiendo. Thank you so much!

I think something else that needs to be noted is that Freon is not something to play with, you can be seriously injured with it, this really isn't for the amateur.

Very helpful and in-depth information, thank you, you guys are outstanding!!!

You'll Split unit explanation is the best what is over here.

So my question is why do you even need a precise charge with the mini split? The accumulator obviously accounts for a slight overcharge because it is designed to run on a various amount of line set. So it seems like you can just keep adding refrigerant until you get a good pressure...

I would appreciate more of a takeaway conclusion headlining this video. The TL:DR version is that on a mini split you can't actually just easily take pressure and temp measurements and determine the refrigerant charge state, and so they are just very very hard for even a trained tech to diagnose. The most practical advice is at the end about 11:00 mark, where you list a couple of conditions where refrigerant is likely low. It's pretty disappointing to me that these units don't give more feedback in general about what the unit is doing, and more feedback in particular when something is amiss. Even in normal op, mine just beeps once or twice, and the remote only lists what your last setting request was. The lack of a diagnostic data out, leads I think to the technicians just throwing up their hands and replacing the whole unit. This happened to my parents on a unit that just wouldn't cool even after many visits by the tech. They had no clue what was going on. They ended up just having to replace the whole thing at $4 grand. It seems you roll the dice with these things and about all you can do in event of a malfunction is check for leaks on the lines and maybe add a bit of refr. in a blind hope that will fix it. If not . . . replace. You bank on the fact that most of them seem to run for 10 or 15 years I guess and cross your fingers.

Thanks for the information 👍 , I look forward to watching more videos like this , Very informative 💯👍😎

Thank you once again for an amazing instructional video and procedures for checking charge on mini split

Can also check the delta T at the indoor unit while on the highest fan setting. Should get 20-25 temp split from return to supply.

Great video and excellent explanation of how to install a mini split system. Thank you, for sharing.

Panasonic inverters Outdoor unit has a PCB. use the test run button to lock in values then charge refrigerant.

What about testing inverter boards in general . Thanks you o great work. Montreal says Hello

Wow, I mean it's really good content, but if you're a beginner watching this video, it will blow your mind because he's spitting out technician jargon at 10x speed. It's like, dude I get it you know your stuff, but I don't. haha!

So you spent 12 minutes and 27 seconds to say that there is no answer to the question in your title! Priceless!!

I’ve seen that the service manual usually tells you what pressure to expect based on indoor / outdoor temps so you can at least verify it’s not low.

the only time beer can cold is acceptable :D

very usefull, thanks a lot , just one clarification ..one above case for refrigerant charging we can only get hint from subcoolings if ts shows low saturated temp then its means refrigerant is less.

Thank you for this amazing video. I would have 2 questions: - Does the saturated temperature vary depending on the ambient outdoor temperature when the unit is running on lowest temperature setting in turbo mode? - Inverter mini splits show on the outdoor unit plate a value of Amps in cooling mode. Example: For a 12000BTU unit = 4,5A If the 4,5A are not reached in turbo mode on lowest temperature should refrigerant be added? Thank you very much Really appreciate your help SR

Hello. Good morning How can I follow the correct sequence of lessons and video sequences

Wow, that was a serious schooling lessons! Excellent, thank you!

Would forced cooling mode like the MHIs have for pumpdown help to check ?

Can you do a check/recharge video on a MrCool Universal heatpump inverter? The plate doesn't have any subcool or superheat on it just a designed max and min pressure. Thanks. BTW - mine has gone into low refrigerant E3 mode and techs are stumped on how to charge

Hey, i've a Panasonic Mini split inverter (only for cooling no heating) it has a constant speed outdoor fan & a capillary metering device & it has a special mode in which the compressor gets locked on its maximum rpm, also in that mode, the indoor blower runs at its maximum rpm. Now, can i measure the target superheat? Using the DBT & WBT and compare it against actual superheat to find the minisplit's proper charge?

very helpful information on mini split thx

I normally use Supply Air Temp, Amp Draw, Suction Pressure, and SuperHeat.....Mixed with some experience. But pull charge and weigh it is best way.

Excellent explanation

Mitsubishi/fujitshu.. you cannot do super heat or subcooling accurately on ANY minisplit system ...

I top them off. Get it running at 100 percent (usually two 1500 watt heaters on the inside unit). I shoot for a saturation heat of 40.

Are there any brands of mini splits that will allow you to set the eev wide open and the fans full on? basically a unit that is made to be able to test it?

How accurate do you need to be when weighing in a charge on a mini split? What if you can't get an exact measurement of the lineset?

Great job

I’ve never understood why the U.S doesn’t make it Celsius at least with HVAC.. So much easier to say below zero is freezing and above is not..

Thanks for sharing this Craig. I don’t mini split a bit complicated

I don’t have very much experience with mini splits or inverters, but I’m 608 certified and worked HVAC for a little while as a service tech. I installed a mini split in my garage. It worked well enough, but being OCD, I wanted to check the pressure. Unfortunately I had a bad hose, and lost some refrigerant, not a lot, but enough that its performance is not so good. There’s no visible drip from the drain line like there was before the leak. I’m just gonna go ahead and add some 410 a little at a time, until the drain line produces a drip again. From what I understand, the test port pressure should be 110 to 160 psi. I noticed your pressure was in the 150 range for all of the demonstration. Worst case scenario, I can purchase a recovery machine and a scale close to what I’ll be charged by HVAC company.

L.G. tech training says to check charge by the delta T at the indoor unit (18-20 F) not by gauges

Gree Vireo mini split units have liquid and suction service port connection at the service valves.

Best video you have done, very well explained thank you!

What about if there is a micro leak on the indoor coil and the customer wants to keep it running and you couldn't pull out the charge because you know it can't pull down a vacuum successfully? Not able to fix leak on coil

Thanks for all the videos and the book. I’m still unsure about the correct refridgerant charge on my mini split. The outdoor unit lists the charge weight and the instructions say that’s for certain lengths of line sets (my outdoor unit can run 5 indoor units). If my total line set length does not exceed the total length in the manual am I ok with just the charge weight listed on the outdoor unit? Some of my line sets are shorter than the ‘max’ length, others are longer, but in total I’m less than the total length listed in the instructions. Thanks.

So you can't check the refrigerant charge accurately?

If the line set is increased by 10 feet how much of an increase of refrigerant should be added charging a unit after evacuating it?

Excellent video sir, thanks for sharing.

Recover weigh back in to factory specs, done.

Another great Video, Thank you

Very articulate but please slow down for us southerners. Good job

Refrigerant pressure compaired to ambient outside temperatures would give an indication of charge level. The system must be off to allow high and low side lines to equalize and raise to ambient air temps. The resulting psi compaired to temprature chart should give some information on state of charge.

Cool vid, thanks for all the content you provide

Thank u for this helpful video God bless

This video is much needed to get the point across basically( don’t use beer can cold don’t you superheat don’t guess because that’s all you’re doing is guessing) RTFM Some of the better manufacturers have dip switches on their control board. Or a software interface module that connects to the control board to your laptop computer with the manufacture software. In the severe situation if for some reason you cannot completely drained the charge and refill it to the manufactures weight of refrigerant. You use the software on your laptop or the DIP switch on the control board to put it into a hard set TEST MODE. It uses software that is hardwired in the control board to take over and use the temperature sensors and pressure transducers throughout the system to calculate and set the indoor blower motor at a set speed that it was designed for testing. It will set the outdoor condenser fan motor into a test mode for airflow over the condenser that was designed just for testing and checking the refrigerant. Using all the sensors and transducers with that software it will set the compressor add a speed and volume flow of refrigerant that was just meant for testing. And then through your software you can read the superheat across your indoor coils because now all the airflow at the condenser and indoor coil are set to the correct CFM for testing purposes only. Or you will be reading your laptop screen with the manufacturer software and RTFM Read the fantastic manual and I don’t mean the installation manual you’ll have to go for training or have access to the maintenance service manual that is different than an installation manual. For that specific make and model for that manufacture to find out what their recommended superheat drop across the coil should be. Only after running these procedures in this order could you even come close to correctly topping off the charge to get the correct refrigerant quantity but only if the outdoor and indoor ambient temperatures are within the testing range specified in the manual. RTFM. If you try to use this method any other way or without the dip switches in test mode or software depending on the ambient conditions indoor and outdoor you may still read a superheat number that looks correct when comparing to the service manual but it will be absolutely wrong because the hardware was not hard locked into the TEST MODE. Some manufacturers do not provide this information or have this capability because they’re very low end units therefore you’re up shit creek without a paddle. Recover all the refrigerant and recharge it to the specific weight and don’t forget to take an account the “ADDER “ for lines at length if needed. Some manufactures on top of a line set adder for refrigerant rate per foot. Also have a air handler BTU adder for the size of each air handler attached to the system. So depending on the size of your system with four air handler’s or nine air handler you may need many ounces more or many pounds more just because of the size of the air handler’s (“. RTFM !!!”) I’m tired of going in to burnt out compressors on VRF systems were somebody with 20 or 30 years more experience than me use the old school method of topping off the system. And then when you tell them what they done and explain how the system works they say. (“ I didn’t know “). Because it’s just a correct way to completely recover all the refrigerant if you own and use a four-cylinder NAVAC Recovery machine it only takes a few minutes to recover the entire charge so what’s the loss no big deal. If you own any other manufacturers recovery machine you’ll be sitting there for a long time on top of a hot room using a garden hose or a bucket of water attempting pathetically to cool down your refrigerant recovery tank. Crying and whining and using the excuse it takes too long to recover the refrigerant and recharge it it’s easier to just top it off. This is where owning and knowing how to use the correct recovery unit for the correct situation comes into play. NAVAC 4-cylinder recovery !!! You can lead a horse to water but you can’t make them drink 🤔 And don’t forget RTFM On some units you have to flip the dip switches on the circuit control board to go into recovery mode and open up solenoid’s that are closing off the refrigerant path possibly through a distributor box blocking refrigerant flow RTFM Otherwise when you perform your recovery there will still be a lot of refrigerant locked in the line set and air handler’s and when you weigh in your new refrigerant charge that you think is correct you are now actually way overcharged. RTFM I come across this a lot coming in behind other people with many many more years of experience than me and who are a lot better at a lot of other things than me I am just a student learning.

Recently had a mini split installed. Technician did not evac the copper lines before turning it on. Its cooling pretty well, but I think should be a few degrees cooler. I wonder if the evap unit is also precharged with refrigerant, or is it empty? Not evacuating the lines let a lot of air and water into the system. It was 85F and 80% humidity the day they installed.

In mini split is better way to recover the refrigerant then change in weight? Thanks.

Do U have a vid on doing a complete recovery ,pressure test and vacuum of the complete system. Thanks for Ur videos

Supposed to be the accumulator must have and eye sight glass in order to see the level of refregerant or any level electronucs just to protect the compressor.

Hello. My English is not perfect. I hope I understand the main statement of this video: Mini split with capillary as throttling method: recharging can be done with superheat measuring Mini split with EEV as throttling method: recharging can't be done with superheat measuring. In this case you have to recover all the refrigerant and then you have to fill in the correct amount of refrigerant. Is this right?

As usual excellent video! So what should be the limit for inverter units i.e I mean what degree of subcooling (condenser side) and degree of superheat ( evaporator side), one should follow? Is there any rule of thumb? Thanks.

Thanks for the precise details. Would you say tolerances are quite wide. If you lost a cup full of gas it continues to work? Say for instance if you opened a valve a quarter turn for half a second and let gas escape would it still likely work? Obviously when disconnecting gauges a bit is lost so I'm wondering if you can put a number on it and say how tolerant the system is with losses in different examples like letting out certain amount of gas on purpose.

I wonder if it might be possible to use an IR camera to view accumulator tank to evaluate how much liquid is in accumulator to evaluate charge of mini-split?

Thanks for the video

The correct of changing a minisplit is to charge it correct from start, take all refreigersnt and way in appropiatley . Check your sat temps. Head pressure. And your diff split. You leave that split alone. If you don't have low loss fittings do not touch that unit . They are way more finnicky

So basically in the winter your air conditioning the outside and the heat from that is blown inside the home. I have always understood that AC was very inefficient.

Bismillahirrahmanirrahim. I can learn the usage of the Refrigerant from you. So, to many to full of Refrigerant, is also not good. Too little, also not good. Thanks. Best regards from Indonesia South East Asia. Wslm.

So main question: if I discharge my system, and refill with proper amount of refrigerant do I need to add oil or does the oil remain in there when I vacuum and recover? Nobody has a clear answer

Starting at 11:47 is the answer. There really is no way to tell, needs to be recovered, tested and repaired for leaks, and then charged with the precise weighted charge for the system. Even at that, charge may have to be adjusted for linesets that are shorter or longer than the baseline which I believe is usually 66 ft in total. Trying to adjust the charge at random can result in damage, not worth taking a chance.

Very good video. So, in some ways, it's a bit like automotive AC. Evacuate and weigh-in the charge. Still not sure why they don't provide a liquid line test port?

thanks, great video

The number one cause of compressor failure is not over charging. It’s a dirty condenser and/or a dirty evaporator. And that’s all there is to it professor. Overcharging is not the #1 cause. It’s liquid slugs or excessive head pressure and excessive compressor discharge temperatures. Keep her clean.

Mini-splits would put us out of business. I would need to hire a computer scientist/plumber/electrician/carpenter/welder/refrigeration tech/salesman...... Good luck finding one of them.

Nice clip. Very interesting. Thank you. I watched it because I am trying to understand better the functioning of an inverter. In a nutshell, if one out of two mini split wall unit is turned off can I assume that the energy consumption of the compression is cut by half, roughly? If not, what would be the ratio. I have 2x12k minis hooked to a 24k compressor.

Great educational video!!!

What is the running pressure range for cooling and heating for R22, R410a and R32. Thanks

Can you go over this same tutorial over a multi zone mini split unit. I have a 3 zone C&H ceiling cassettes ( only 2 zones being used). One unit runs very cold the other is not . I cant find the leaks if it is leaking.

Hey I know this was old but I see a lot of people having trouble with there inverter mini splits showing a pc04 error code ,I was having trouble with my Apoodr given a pc04 code and going into a brief defrost randomly and i cured mine by taking it off the twin breaker and I can put it in the twin and it will throw the code and take it off and it stops so I was hoping I could see if you would make a video explaining and exploring this because I see alot of people haveing thes problems and it would help them if they had this information, thanks for your videos and hope to see one about this problem and cure

thank you teacher

What about checking the operating pressure in turbo mode with the compressor at full capacity?

Continue to teach us and the functioning of the mini split unit? Wat is specific length on a mini split unit,,,on wen u supposed to add refrigerant????

how do you like Cooper and hunter mini split?