Mini-split charging process

[Albromyle]

Hello everyone, I'm new to this board!

I have a question in regards to the mini-split charging process. I've been rather very thorough on the entire installation. However, one thing I was not expecting was an issue I had where I tightened the nut a bit too much, and it broke off the 1/4 copper flare and I lost the pre-charged freon.

So, I got additional r410a and checked beforehand to see if I still had any additional R410A by opening the valves, and with having a pump and such ready at my side. However, there was no additional freon left so I got another r410a canister and after watching countless videos, and viewing many posts from professional and diy'ers on the process, Im sure I have it down.

I did my calculations, got my scale, weighed it all in and it was going fine, I did the charging in bursts so that I would not overflow the system too quickly with liquid refrigerent. However, my max capacity that is labeled on the air conditioner 84.7oz (5lb 4.7). It was going good until after reaching 3lb (1.3oz), where it acted like as if it did not want to add anymore, it was extremely slow, only adding .1 oz more of regrigerent every 5-10 seconds, if that. So I shut it off to come here and ask for some help.

According to the unit, I should be able to fill it up to 5lb 4.7oz, but I've only got 3lb 1.3oz atm inside the unit, any suggestions at to why it slowed down, is it actually topped off already and I somehow missed the "additional" r410a that was somewhere in the unit/compressor that caused the rest of it to not completely leak the first time around?

I should mention, the unit said that it comes with refrigerent enough for 15 feet of lineset, however, I do not have 15 feet of lineset, I've more along the lines of 10-11 feet (if it was laid flat and not curved like an L on the wall). Is this potentially the reason why it stopped filling because I have a shorter amount of lineset then what the unit originally came with?

Thanks.

 

[JackDiddly]

FIRST AND MOST IMPORTANTLY FOR EVERYONE READING THIS: FREON is a registered trademark by Dupont a manufacturer of REFRIGERANT..................

Most of these units are indeed factory charged for a minimum amount of feet in lineset. They have a Service valve on them that allows you to install your lines to the indoor unit then TEST AND VACUUM your lines ensuring through that process that there are no leaks, all BEFORE releasing the factory charged refrigerant.
Sounds like you skipped a few key details. Hard to believe you had recovery equipment at the ready. Once you Broke the valve and the charge released- the lines likely would need a test and vacuum again before re-charging. The pressure in your bottle and the line will only equalize without vacuum. I have never had an issue getting a factory charge back into a unit that was under vacuum. The other thing to consider is that the Factory requirements for the lines were met at installation (Where is the install manual? 15ft may have been a minimum requirement)... Most techs I know would tell you that a number of the problems seen in the field on mini-splits come from poor installation.

 

[Gerald O]

I should mention, the unit said that it comes with refrigerent enough for 15 feet of lineset, however, I do not have 15 feet of lineset, I've more along the lines of 10-11 feet (if it was laid flat and not curved like an L on the wall). Is this potentially the reason why it stopped filling because I have a shorter amount of lineset then what the unit originally came with?

Thanks.

No. A short line set should not be a factor in causing you to be unable to charge to the correct level. The compressor is able to contain the entire specified charge irrespective of line length. Line length is only a factor in making small adjustments to the standard charge.

Do not make your lines shorter than the specified minimum, as that will affect performance.

There is a lot of confused and missing information in your description of the problem and how it occurred. It is not at all clear what you have done. Breaking off the flare fitting? You didn't follow directions did you. I think it's time to hire a pro that knows what he is doing.

 

[Gerald O]

According to the unit, I should be able to fill it up to 5lb 4.7oz, but I've only got 3lb 1.3oz atm inside the unit, any suggestions at to why it slowed down, is it actually topped off already and I somehow missed the "additional" r410a that was somewhere in the unit/compressor that caused the rest of it to not completely leak the first time around?

It needs to be evacuated with a recovery pump (into a recovery tank) to be sure that its empty before recharging. Get the technical service manual for your unit for the correct procedure.

 

[CWO4GUNNER]

I sympathize with you. But truly this is a classic example of why a nitrogen pressure test is conducted to check for leaks in the lineset. Had you used nitrogen and discovered the bubble leak at the fitting under positive pressure (cannot in a vacuum), a cracked fitting due to over tightening would have resulted in loss of harmless, needless nitrogen requiring only a repair and re- pressure again with nitrogen BEFORE placing the system into a vacuum to remove "moisture" BEFORE releasing the charge into the confirmed leak free system.

What to do now...Start over from scratch and know what your doing. EVERY step!

 

[CWO4GUNNER]

Assuming, you did all the steps correctly and the entire system circuit is now leak free and in a vacuum, not just the lineset and evaporator side but the condenser side circuit as well (the entire system circuit). If the entire system circuit as a whole has stopped accepting the prescribed charge by weight, then stopping the charge letting it equalize for some time should allow the charge to continue until you have reached the manufacturer's required refrigerant charge including lineset length calculated charge.

 

[Albromyle]

Assuming, you did all the steps correctly and the entire system circuit is now leak free and in a vacuum, not just the lineset and evaporator side but the condenser side circuit as well (the entire system circuit). If the entire system circuit as a whole has stopped accepting the prescribed charge by weight, then stopping the charge letting it equalize for some time should allow the charge to continue until you have reached the manufacturer's required refrigerant charge including lineset length calculated charge.

Finally, someone with an answer that I can agree with that didn't assume I'm a complete idiot. I did that and it worked just fine.

I have ZERO leaks, I redid my entire flare, I'm secure now, the system was also already vacuum'd out before application. I've also tested it by applying multiple solutions on the joints, as well as letting it sit for a day with no leakage.

All of this I've already explained in my op. Too many people think DIY'ers are these dumb idiots. Not cool.

 

[JimL]

uhhhhhh letting it sit isn't going to do ****. pressure in the can is the same as in the system now. You can either heat the can up or start the unit and continue weighing in the charge as it is running in cooling. I would do the second one.

 

[JackDiddly]

No offense ,but I have installed a number of those systems, I can't figure out for the life of me if you followed the proper procedures in the first place why you would have put a wrench on your flare fitting after the charge was released?

 

[CWO4GUNNER]

You can start the unit and continue weighing in the charge as it is running in cooling.

Without the rhetoric, the above portion of JimL suggestion is correct. Only you having charged the unit with liquid, albeit cautiously(???), for your sake offering time insuring no liquid would damage the compressor. I personally not in a customer rush always weigh in the charge as a vapor.

But yes by all means you can proceed and start the unit and continue weighing in the charge as a VAPOR ON THE LOW SIDE ONLY! This to be on the side of caution, albeit much slower.

 

[JackDiddly]

If I am not mistaken 410a is a blended refrigerant and the only way to properly charge with it is upside down in liquid state?

 

[CWO4GUNNER]

YES! But using your gauge set to throttle in liquid to vapor is risky...There are charging devices out there that make charging blended refrigerants as a vapor possible which is my point here. Personally I use the Vapor-vue which has a built in evaporator and sight glass.

 

[JimL]

Bleh if you knew how the mini's work, you could dump liquid in all day.

Metering device is outside, so effectively you are dumping liquid into the evaporator… By the time it gets back to the compressor it would be "evaporated"


Couldn't tell ya how many leaker r22 units I have dumped from 1 to 10lbs into every year. Just straight liquid, and the over charge them so they will "last all summer". Effectively sending liquid back to the compressor. They keep on chugging lol

 

[CWO4GUNNER]

Couldn't tell ya how many leaker r22 units I have dumped from 1 to 10lbs into every year. Just straight liquid, and the over charge them so they will "last all summer". Effectively sending liquid back to the compressor. They keep on chugging lol

Wow if your still referring to mini-splits there, you almost make them sound bullet proof and that make me feel good about my garage installation. But with the higher R410a pressures and inverter technology, Ill be satisfied if mine is still working 6 years from now.

 

[bazar01]

I personally not in a customer rush always weigh in the charge as a vapor.

But yes by all means you can proceed and start the unit and continue weighing in the charge as a VAPOR ON THE LOW SIDE ONLY! This to be on the side of caution, albeit much slower.

You should get more experience handling refrigerant blends before giving any advise or recommendation.

 

[LS6 Tommy]

You should get more experience handling refrigerant blends before giving any advise or recommendation.

X2!! There's some other not-so-well informed statements in this thread, too...

Tommy

 

[Jackfre]

The way the Mshp manuf explain it in their training programs is that 410a will separate in the vapor state in charging, not giving you the "real" product. They are emphatic in this statement. 410a doesn't handle like 22. While it may be the season for it, charging with vapor is kinda like Trick or Treat!

 

[monkeyspanners]

If the system was empty and vacuumed, i'd dump the factory charge in and then let the system sit for a while before running, if you run it up in heating mode first any liquid in the lineset will have to go through the indoor unit and metering device and 'condenser' before reaching the compressor.

 

[CWO4GUNNER]

If the system was empty and vacuumed, i'd dump the factory charge in and then let the system sit for a while before running, if you run it up in heating mode first any liquid in the lineset will have to go through the indoor unit and metering device and 'condenser' before reaching the compressor.

Bravo-Zulu! Very well put, helpful, and right on the money.