How to charge a mini split?

[bzinsky]

So I installed 20 lg mini-splits, I'm not an hvac contractor but I did go to the LG training course at their regional headquarters. I tried hiring people but they had little experience with mini-splits and thought I was extremely ****. I know they are out there, but had no luck finding anyone good.

I wired them, flared them, pressure tested them, vacuumed them down to 40-50 microns, and fixed all the leaks I could find (the hvac contractor swore I didn't need to use the LG flarenuts, he was very wrong). It turned out well it the end, but I have a few issues with the charge.

The linesets max length is 41 ft before I need to add r410, a few were 45-50 feet, I was hoping it'd be ok, but it's a noticeable difference in output. I'd like to add refrigerant to them. I know how much to add, just not how to add it.

I have 1 unit that seems to have leaked it out. Atleast from my basic troubleshooting of having both units up and running, hearing a compressor, not getting a cold line, and opening the shrader valve for a milisecond which felt like it had very little pressure on it. I can locate and repair the leak on my own, but have no idea what to do after that. ( I do have to point out this particular unit blew a fuse on the outdoor unit somehow, only one to do that, I replaced it and it hasn't happened again. It wasn't the fuse in the disconnect, it was a fuse inside the unit right where you make the electrical connections)

I have a vacuum pump, micron gauge, nitrogen tank, core tool, couple nice hoses, adapters, etc. Basically everything that was needed nitrogen purge them and vacuum them and start them up.

I tried google, but most of the advice and how-to left is tailored to people that already know how to charge traditional systems, but need specifics on the mini-splits.

Thanks in advance

 

[Trey T]

Request for a LG installation manual and it should tell you the requirement for charging the system.

For Daikin systems, it's the weight of the refrigerant that you charge to the system, so you'll need a scale with enough precision. I think the HF digital scale can do it.

For the length of lineset, Daikin specify the max length you can have on a system and/or elevation difference b/t the two units.

 

[bzinsky]

Also I have to add, saw a lot of people recommending yellow jacket tools on here. Had 3 things from yellow jacket, 2 of them leaked, the last had a manufacturing defect that I was surprised it didn't leak.

Went with Appion and it was rock solid

Also from all the stories I was expecting it to take forever to vacuum. I guess I got the right equipment.
this pump
http://www.amazon.com/gp/product/B001P7C7QM/?tag=atomicindus08-20
this hose
http://www.amazon.com/dp/B008FM7QCU/?tag=atomicindus08-20
this core tool
http://www.amazon.com/dp/B008HQ2EZ8/?tag=atomicindus08-20

500 microns in about 15 seconds, 75-80 microns in 5 minutes, 40-50 microns in 10, all it took was 10 minutes and when you close off valve it would rise to about 75 microns and stop from there. From everything I read that's extremely fast.

 

[bzinsky]

Request for a LG installation manual and it should tell you the requirement for charging the system.

For Daikin systems, it's the weight of the refrigerant that you charge to the system, so you'll need a scale with enough precision. I think the HF digital scale can do it.

For the length of lineset, Daikin specify the max length you can have on a system and/or elevation difference b/t the two units.

I know how much to charge and lineset lengths, I just don't know how to charge.

For the units that didn't leak and just need more because of the lineset length, I'd assume there is a different way to add refridgerant to that then the one that completely leaked out.

 

[Trey T]

Youtube it and it will tell you how to charge R410a liquid (tank upside down). You always charge on the suction side if that's what you're wondering.

Again, you charge the refrigerant by weight per line set length and LG install manual will tell you. It's important that you read your install manual... no seriously, read it from front to back; reading and understanding it will set a profesionals apart from the newbies.

 

[bzinsky]

Youtube it and it will tell you how to charge R410a liquid (tank upside down). You always charge on the suction side if that's what you're wondering.

Again, you charge the refrigerant by weight per line set length and LG install manual will tell you. It's important that you read your install manual... no seriously, read it from front to back; reading and understanding it will set a profesionals apart from the newbies.

Things I don't know - where to get r410a, I don't know what it's even stored in, I don't know how to weigh it, I don't know how it gets from the storage tank to inside the unit, I don't know how to get it into the system without introducing air into it, I don't know how to take a system that leaked out, and start over again and how that process is different from simply adding refrigerant to one that didn't come with enough, etc. How about the 3 gauges with hoses coming out of it that every hvac technician has and I have no idea what they are for, I don't know if I need that.

Things I do know - How important critical charges are, the exact specifications of what the system needs, how important having no air or moisture in the system is, and the entire process and theory of transferring thermal energy from the air, earth, or water into a conditioned interior space, how to open and close the king valve, where the one and only service port is, etc etc.

 

[slice]

I have spent 25 yrs in the hvac field. All the above question you ask are all life skills of the hvac man, learned over many yrs. if you want it to be right and I am sure you do. You need to know how many oz of freon the unit holds with 41 ft of line set. Then find your local hvac guy and pay him to do it. He has the TOOLs and knowledge to do it correctly.
Not the most pc answer u wanted but do it right first time or pay out the a__ later.

 

[walrus]

If units have leaked you have to evacuate unit and then add correct amount of r410a. You don't know how much leaked out so you don't know how much to add.

 

[BD1]

If units have leaked you have to evacuate unit and then add correct amount of r410a. You don't know how much leaked out so you don't know how much to add.

410A is a precise mixture of different freons. Normally if you lose 10% of system volume entire system must be reclaimed and NEW FREON ADDED . You cannot top it off !
This 410 runs at high pressure, over 450 PSI . Call a professional and you will be money ahead and maybe even prevent a lawsuit due to injury.

 

[bazar01]

Things I don't know - where to get r410a, I don't know what it's even stored in, I don't know how to weigh it, I don't know how it gets from the storage tank to inside the unit, I don't know how to get it into the system without introducing air into it, I don't know how to take a system that leaked out, and start over again and how that process is different from simply adding refrigerant to one that didn't come with enough, etc. How about the 3 gauges with hoses coming out of it that every hvac technician has and I have no idea what they are for, I don't know if I need that.

Things I do know - How important critical charges are, the exact specifications of what the system needs, how important having no air or moisture in the system is, and the entire process and theory of transferring thermal energy from the air, earth, or water into a conditioned interior space, how to open and close the king valve, where the one and only service port is, etc etc.

Honestly, things you don't know are the hvac tech basic skills.
Go to a tech school and learn the hvac technician course basics.
You don't need to complete the whole course. Maybe attend one or two semesters.
Then after that, you need to pass the EPA608 license test to buy refrigerants.
Good luck.

 

[bzinsky]

Honestly, things you don't know are the hvac tech basic skills.
Go to a tech school and learn the hvac technician course basics.
You don't need to complete the whole course. Maybe attend one or two semesters.
Then after that, you need to pass the EPA608 license test to buy refrigerants.
Good luck.

so funny when you guys pushback whenever somebody wants to diy something in your trade. Not sure if you're like a blacksmith from the iron age protecting your trade secrets, or its arrogance and you think us plebians can't possibly stuff some refridgerant into a chamber the proper way. Either way, both reason are rediculous, spare me the "hire a pro" speach.

 

[acmikee]

STOP
you need to be licensed to buy any refrigerant
there is NO way you evacuated the system to 500microns in 15 seconds
hire a hvac contractor and do it the right way

 

[walrus]

The R410a should have been added before you opened the valves, under vacuum. There is a way on a Fujitsu to pull all the freon into the outdoor unit, shut the valve and then you'd be at square one again. pull the line set and indoor unit down to 500 microns, add the r410a. With Fujitsu it has to be in cooling mode but I forget the details. Its in the instructions though.

In order to fix the leaker you need a recovery unit, pull out the remaining R410a. Before I did that I'd get an electronic leak detector. Find the leak and then pull out R410a into recovery unit. Fix leak, nitrogen test to 500psi( thats the figure on a fujitsu, LG may be different???. The problem you will have if all the R410a leaked out you may have significant moisture in the system. You may have to pull it down several times braking the vacuum with nitrogen.

The R410a comes in a tank, you place it upside down on a digital scale, zero out scale, open valves and if system is under vacuum it should pull it in. Stop(shut valve on tank) when scale hits the number of lbs, ounces your system needs.

The next thing is, you need a EPA license to handle freon. Technically from what I understand you don't need a license to handle R410a but I doubt any supply house is selling it to you without one.

 

[BD1]

so funny when you guys pushback whenever somebody wants to diy something in your trade. Not sure if you're like a blacksmith from the iron age protecting your trade secrets, or its arrogance and you think us plebians can't possibly stuff some refridgerant into a chamber the proper way. Either way, both reason are rediculous, spare me the "hire a pro" speach.

Nothing wrong to do it yourself IF you know what you are doing. 20 systems are costly just to purchase. IF or when he destroys compressors due to lack of knowledge may cover the cost of a professional to do it right. Not to mention when he gets 20 calls because it's warm inside.
Sure he might be able to stuff refrigerant into the system, anybody could. It may work. Will it be efficient ? It won't . Will it cost more to operate ? I would say so.
There is more to just dumping the stuff in. It could work for a while and then he'll be replacing compressors which will not be covered under warranty because of improper installation.

 

[JackDiddly]

Why does everyone think they can come online and learn a trade in a few videos and then get pissed when the professionals call them out? The questions you are asking would be answered if you spent some real time learning this trade?
Every mini-split I have ever worked on will require an adapter at the service port - it is larger than the standard fittings. Critically charging is the only approved method for almost all of these units. Which means, you will need refrigerant, a scale, gauges, adapter and a solid understanding of what R410a is and its proper charging techniques. If you are asking for help on how to connect all of this to make the magic happen I don't care how much you don't want to hear - HIRE A PROFESSIONAL!

 

[Jackfre]

I muffed the install on my daughters dual Fujitsu unit a couple years ago. I found a very minute leak, but minute over time equals the whole charge leaked out. I did a triple evacuation of the system and weighed in the total charge, meaning you need a digital scale, and you charge in the liquid state (bottle upside down). Giving it a shot of refrigerant may buy you some time, but you are just pushing the problem down the road and the resulting problems will be greater.
As noted, 410a is a blend of chemicals so to get the best out of it you need to recover the remaining charge, if there is any, and weigh in the total specified charge.

 

[Trey T]

OP: You have a lot of questions and those questions will irritate the hell out of the ppl on this forum and others. I highly suggest you spend about 8hrs, no seriously, to do your research and compile your questions - start with youtube. During that time, you'll figure out what questions need to be asked and what not; right now, you're not really asking the "right" questions.

 

[rlitman]

410A is a precise mixture of different freons. Normally if you lose 10% of system volume entire system must be reclaimed and NEW FREON ADDED . You cannot top it off !

That's if you LOSE refrigerant. But in a mini-split, the compressor comes pre-filled with a measured weight of charge that is designed to be used with linesets up to a specific length. When the length exceeds that, the instructions will state exactly how much weight of charge to add per length of additional line. That's what the OP is trying to do.

For Daikin systems, it's the weight of the refrigerant that you charge to the system, so you'll need a scale with enough precision. I think the HF digital scale can do it.

That's for much more than just Daikin. Just about anything. For R134a, I have a luggage scale, and hang the cylinder from it. It easily reads to the closest ounce is more than acccurate enough, and is super cheap.
But for R410a you need to charge from liquid. If you can find a cylinder with a dip tube for upright liquid dispensing, then the luggage scale will work. If not, then you need a proper platform scale. Most platform scales are not accurate enough to read to the nearest ounce, so you're going to need something expensive to use for charging AC systems (though looking closer at the 70lbs HF scale, it looks like it might be good enough for the job).

STOP
you need to be licensed to buy any refrigerant
there is NO way you evacuated the system to 500microns in 15 seconds
hire a hvac contractor and do it the right way

License required. Correct.
Evacuating to 500 microns in 15 seconds. Yeah, it's normally possible IF you're only evacuating your manifold's hose (i.e. not a whole system). Though he does say he used a monster 8CFM pump with a truly huge 1/2" hose and removed the valve core while vacuuming. Not things I would normally expect to see done on a mini-split (or even on a system that takes 30+lbs of charge), because with a little patience, a regular 1/4" hose and 2CFM pump and leaving the schrader in place will still get good results. But I wouldn't go so far as to say 15 seconds is impossible, considering the tools used.

 

[Trey T]

Guys: not "license", it's "certificate". This has been floating around the internet for decades and I'll clarify it.

It's not tomato-or-tomato, it's important because license are issued by local or state gov't while certificates are issue by an organization or sometime gov't. They bear two different meaning in the US; (1) licensed to provide a service and (2) certified to practice under a licensed personnel.

i.e. to provide HVAC service in Texas you need HVAC license issued by TDLR. I don't think it's a must and the law has provisions for if-and-but.

Technically, you need to be "certified" to "handle" refrigerant. I don't think EPA mention about buying or selling, they care about how you handle the refrigerant safely. In actuality, HVAC suppliers will ask for your certification before they can sell it to you.

 

[brewchief]

That's if you LOSE refrigerant. But in a mini-split, the compressor comes pre-filled with a measured weight of charge that is designed to be used with linesets up to a specific length. When the length exceeds that, the instructions will state exactly how much weight of charge to add per length of additional line. That's what the OP is trying to do.



That's for much more than just Daikin. Just about anything. For R134a, I have a luggage scale, and hang the cylinder from it. It easily reads to the closest ounce is more than acccurate enough, and is super cheap.
But for R410a you need to charge from liquid. If you can find a cylinder with a dip tube for upright liquid dispensing, then the luggage scale will work. If not, then you need a proper platform scale. Most platform scales are not accurate enough to read to the nearest ounce, so you're going to need something expensive to use for charging AC systems (though looking closer at the 70lbs HF scale, it looks like it might be good enough for the job).



License required. Correct.
Evacuating to 500 microns in 15 seconds. Yeah, it's normally possible IF you're only evacuating your manifold's hose (i.e. not a whole system). Though he does say he used a monster 8CFM pump with a truly huge 1/2" hose and removed the valve core while vacuuming. Not things I would normally expect to see done on a mini-split (or even on a system that takes 30+lbs of charge), because with a little patience, a regular 1/4" hose and 2CFM pump and leaving the schrader in place will still get good results. But I wouldn't go so far as to say 15 seconds is impossible, considering the tools used.

I got to 500 microns in 15 seconds with my 8 cfm pump but it was just a 2 foot hose, my gauge and a 5 foot hose leading to my manifold.
Charge needs to be weighed in, leaky unit needs any remaining charge pulled, leak fixed and new charge weighed in.


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[DGarrett]

OP - as a near-total DIY guy myself, the trade guys above are speaking wisdom. This is one job that if you don't have the tools (or even know what a manifold gauge set is), know how to use them, and have a real solid understanding of the system and the refrigerant, you'll mess it up in an expensive way.

I'm EPA609 certified, mobile only, and do my own AC work on my vehicles. I took training classes - hands on experience from an instructor who knows is invaluable - read books, and got certified. Spent a lot of money on the right tools. This IS something a DIY can do, but there's a steep learning curve and, as frustrated as you are with local installers, you might find the cost/benefit ratio for a single DIY install outweighs the cost of a pro.

Even though I'm certified under 609 and have mobile experience and tools, *I* wouldn't touch it myself. I'd keep calling to find a pro for this one, or pony up and call the manufacturer to help me find the right person.

I'm planning on putting in a mini split in my garage too... Let's see if I follow my own advice.

Good luck.


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[LS6 Tommy]

Things I don't know - where to get r410a.

Legally, you can't if you're not certified. I wouldn't trust the quality of any refrigerant someone was willing to sell "under the table".

Tommy

 

[Trey T]

Legally, you can't if you're not certified. I wouldn't trust the quality of any refrigerant someone was willing to sell "under the table".

Tommy

Yup. I agree. When I was looking for R22 to service my other home, I was thinking about craigslist but it can be a big headache just to save $50.

 

[404]

To OP: The thing with the gauges is called a manifold gauge set.
Look at some vids for examples of use.

https://www.youtube.com/results?search_query=how+to+use+a/c+manifold+gauges+

IN your case need a gauge set that is good to the pressures of R410A.

 

[404]

R410A on Amazon. Lol.

http://www.amazon.com/s/?ie=UTF8&ke...vptwo=&hvqmt=e&hvdev=c&ref=pd_sl_12jjhaidtk_e

 

[404]

Mastercool gauge set.
http://www.amazon.com/dp/B00LUZTTL0/?tag=atomicindus08-20

 

[404]

Charge Scale:
http://www.amazon.com/dp/B000QS2XQK/?tag=atomicindus08-20

 

[rlitman]

Mastercool gauge set.
http://www.amazon.com/dp/B00LUZTTL0/?tag=atomicindus08-20

Because R410a must be charged with liquid, you should use a manifold gauge set with a "window" to be sure you are sending liquid. That set does not have a sight glass.

Here's a similar one with a sight glass:
http://www.amazon.com/dp/B003L22Q0Q/?tag=atomicindus08-20

 

[404]

Because R410a must be charged with liquid, you should use a manifold gauge set with a "window" to be sure you are sending liquid. That set does not have a window.

A window is better, sure. What are the issues if the tank is the correct way up and still has liquid in it?

 

[404]

Manifold with extra window dingus.

http://www.amazon.com/dp/B00B3W9W9E/?tag=atomicindus08-20

 

[404]

Gauge with window and extra port so vac/recovery and refrigerant can be connected at same time.
http://www.mastercool.com/product-c...olds/r410a-r22-r404a-4-way-aluminum-manifold/

 

[rlitman]

A window is better, sure. What are the issues if the tank is the correct way up and still has liquid in it?

Well, there's only one simple way to know for sure if you're sending liquid.
Maybe you think the tank has a dip tube but it does not (or vice versa).
The sight glass has other uses too... (though not so much on a residential system).
Anyway, if you're spending for a set of gauges, it's worth the extra couple of bucks. If you already have the manifold, it'll still work without the glass.

 

[404]

Well, there's only one simple way to know for sure if you're sending liquid.
Maybe you think the tank has a dip tube but it does not (or vice versa).
The sight glass has other uses too... (though not so much on a residential system).
Anyway, if you're spending for a set of gauges, it's worth the extra couple of bucks. If you already have the manifold, it'll still work without the glass.

In the old days we would open the valve and see what came out, gas or liquid. Out of fashion now I suppose.

 

[bazar01]

In the old days we would open the valve and see what came out, gas or liquid. Out of fashion now I suppose.

What the .... ?

 

[404]

What the .... ?

Yes?

 

[trainer]

In the old days we would open the valve and see what came out, gas or liquid. Out of fashion now I suppose.

And hook a hose up to the can of r-12, then open'er up to blow the dust out of the condenser coils.

 

[brewchief]

And hook a hose up to the can of r-12, then open'er up to blow the dust out of the condenser coils.

Ahh the smell of summer

 

[LS6 Tommy]

R410A on Amazon. Lol.

http://www.amazon.com/s/?ie=UTF8&ke...vptwo=&hvqmt=e&hvdev=c&ref=pd_sl_12jjhaidtk_e

I should have been more clear. The EPA doesn't require certification to purchase R410A, but they DO require it to handle R410A. In other words, you can BUY it, but not USE it. Most, if not all, supply houses own rules require the cert for sales.

Tommy

 

[monkeyspanners]

so funny when you guys pushback whenever somebody wants to diy something in your trade. Not sure if you're like a blacksmith from the iron age protecting your trade secrets, or its arrogance and you think us plebians can't possibly stuff some refridgerant into a chamber the proper way. Either way, both reason are rediculous, spare me the "hire a pro" speach.

It can be an uncomfortable feeling admitting you don't know how to do something, but there is no need to get an attitude because you feel inadequate

Personally i don't mind people diy'ing my trade, i have my own youtube channel showing how to do stuff, but it does bother me when people do it wrong, release refrigerants into the atmosphere etc, we have a lot of new regulations to work under to minimize emissions so it is frustrating to hear when non trained people have such a cavalier attitude to working practices we take seriously.

You weight the additional charge in after leak checking and vacuuming the line set but BEFORE you open the valves on the outdoor unit...

I would not pick a manifold with a sight glass for use with R410A, the systems can run over 600psi in heating mode, there have been cases of the sight glasses letting go, infact a friend of mine spent some time in hospital due to one hitting him in the face.

Your vacuum time seems too quick, i would have been checking to make sure all the taps and valves were open, my suspicion would be that the line set was not vacuumed correctly.

 

[danski0224]

So I installed 20 lg mini-splits, I'm not an hvac contractor but I did go to the LG training course at their regional headquarters. I tried hiring people but they had little experience with mini-splits and thought I was extremely ****. I know they are out there, but had no luck finding anyone good.

I wired them, flared them, pressure tested them, vacuumed them down to 40-50 microns, and fixed all the leaks I could find (the hvac contractor swore I didn't need to use the LG flarenuts, he was very wrong). It turned out well it the end, but I have a few issues with the charge.

The linesets max length is 41 ft before I need to add r410, a few were 45-50 feet, I was hoping it'd be ok, but it's a noticeable difference in output. I'd like to add refrigerant to them. I know how much to add, just not how to add it.

I have 1 unit that seems to have leaked it out. Atleast from my basic troubleshooting of having both units up and running, hearing a compressor, not getting a cold line, and opening the shrader valve for a milisecond which felt like it had very little pressure on it. I can locate and repair the leak on my own, but have no idea what to do after that. ( I do have to point out this particular unit blew a fuse on the outdoor unit somehow, only one to do that, I replaced it and it hasn't happened again. It wasn't the fuse in the disconnect, it was a fuse inside the unit right where you make the electrical connections)

I have a vacuum pump, micron gauge, nitrogen tank, core tool, couple nice hoses, adapters, etc. Basically everything that was needed nitrogen purge them and vacuum them and start them up.

I tried google, but most of the advice and how-to left is tailored to people that already know how to charge traditional systems, but need specifics on the mini-splits.

Thanks in advance

Far as I can tell, all of your questions, issues and basic troubleshooting are covered within the installation manual.

If not, then they should have been covered in the factory training course. You should have received additional materials on the equipment.

Mini-splits do not operate in the same way as a typical residential split system. If you had systems with leaks, it will be best to address the leaks, recover what is left, evacuate with a micron gauge and then weigh in the correct amount of refrigerant using a scale.