Loading... 952 view(s) 2 min read

What are Pre-Charged Line Sets?

Sales Representative

You often send us questions about pre-charged line sets, what they are, how they work, and which ductless mini-splits can (or can't) use them. Here are the answers you need to know.

What are Pre-Charged Line Sets?

During a normal HVAC installation, a professional needs specialized equipment and training to connect refrigerant lines. They must properly measure, vacuum, and charge the system. This is essential to effective and efficient performance. Pre-charged line sets don't need any of that. They plug in relatively quickly and easily, because they come straight from the factory sealed and pre-charged (hence the name) with the appropriate refrigerant.

How Do Pre-Charged Line Sets Work?

Connect the custom lines to the custom condenser, tighten everything up, open the valves, and you're up and running. The specialized fittings on the condenser and line prevent any refrigerant from escaping during installation.

Which Mini-Splits Use Pre-Charged Line Sets?

To the best of our knowledge, MRCOOL DIY ductless mini-splits are the only ductless split systems that currently use this kind of line set. There could be some knock-offs out there. For right now though, no other company supplies pre-charged line sets on anything close to the same scale. Basically, if you want a ductless unit with pre-charged line sets, buy a MRCOOL DIY. Now, we must specify that not all MRCOOL ductless mini-splits offer this capability. The MRCOOL Advantage, and Olympus products all use conventional line sets. An installer must connect, vacuum, and charge these models just like any other normal mini-split. So don't buy a MRCOOL Advantage to save a few bucks and expect it to be as easy to install as the MRCOOL DIY. Same brand, different products.

Questions or Comments?

Do you still have questions about these or other products? Or do you just want to tell us what you think? Let us know here, on Facebook, or on Twitter.

70 comments

Leave your comment

Your email address will not be published

charles

When connecting a new evaporator coil to precharged condenser, aren't you supposed to evacuate the coil and lines?

Thank you Kyle your response is very helpful regarding precharged will not work with the MrCool signature series central AC. It comes precharged for 15ft, but the distance between the condenser and evaporator coil is 35 ft Thru the attic (25 ft going under the house). So what are my options, please? Do I need to add refrigerant based on the extra 20ft?

Dan Cox

My 5 month old 4-5 ton universal outdoor unit is being replaced under warranty. This install used the No-Vac precharged 25' line set. Am I able to close all the valves on the compressor and air handler, and remove lines from old outdoor unit (in reverse order of install), and put the lines back on new unit without a vac and recharge?

Donald Russell

Hi Kyle If the lines are only 9 feet- on a mini split - how bad would it be to just secure the non vacuumed lines and open the Pre charged unit? Thanks Don

Mike

If I order a multi-unit mr cool can I get them with different line sets like two 25ft lines and one 16ft line ? Or do they all come the same length .

Jason Welch

Can you pull a vacuum on the novac line set if you loose charge due to a leak?

Dick

We had a new 5 ton A/C unit installed about 2 months ago. Last week it didn't cool down. The guy who installed the new A/C guy came out and after running tests said the line set was leaking somewhere which was under the cement and needed to be replaced. He quoted $1200 to install a new line set. Is this about normal what it should cost? The old line was under the cement, so he ran the new line through two walls and then outside the house, I wanted cleaner installation, but he said he could not bend the line set to a 90 degree angle or use elbows. So now we have a big black thing coming out our side of our house through a laundry vent with a bow in it connected to the new A/C. I can't believe the replacement line set has to look like this. If he used 2 90 degree elbows the line set could have run next to the house out of the way and look more professional;. Am I wrong?

Bert

Precharged lines are too long. What do we do with the excess?

Bob DeGraaf

How can I buy a 25’ line extension

If I get a MrCool Central air condenser that is precharged, can I connect it to a precharged 25ft mr cool set to connect to the evap coil or not? if the set is filled with the refrigerant and the condenser also has enough for 15ft, wouldnt that be too much refrigerant? if so what are my options? Also if I needed 35ft for the condenser and it only has enough for 15ft it means I need to add a refrigerant but how will I know how much more I need

Robert Williams

I'm purchasing the 2 Ton 15 SEER MrCool Signature Central Heat Pump Condenser - MHP15024A. It looks like it comes with 15ft of charged interconnecting tubing. I need to go 30ft. What should I buy?

BruceR

I realized I undersized my 12k BTU unit and need to replace with an 18k unfortunately. It's a studio cottage that is 450sf that is super well insulated, so it seemed like the right size. But it has three french doors, a sloped ceiling that reaches 11 feet and a dozen or so windows. It does not get warm enough or cold enough in outdoor temp extremes. So I want to fix it with a new 18k unit and sell or donate the smaller unit. I was told by a dealer that I can buy the 18k BTU unit and just disconnect the compressor and indoor unit and I would not lose the charge in the 25ft line that is already embedded in the walls. Does that make sense? Any other suggestions are welcome.

Gary DuCharme

Do you think the pre charged line set connection is superior to the standard line set flares? Can they leak at the indoor and outdoor unit if not properly installed?

Marci James

We are looking into a MR. Cool DIY Dual Zone Minisplit. The first level will work with 16ft line, however the 2nd level needs a 25ft line. I’ve read that I can’t fix and match different line sets but can the two 16ft ones be attached together and work for both downstairs and upstairs as one line or do I need 2 separate lines.

Mark Anderson

Is MRCOOL DIY compatible with concealed air handlers?

Ray

Do Mr.cool DIY come with base pan heaters? Do they make multy zone DIY units ?

Ernest

How many btu’s do you recommend for a 35 ft motorcoach?

Jude

If you remove a mr. Cool no vac line set does it reseal?

christopher brown

what does pre-charged line set mean? does it mean the line-set has only been vacuum? Or is there refrigerant in the line-set? Or both, vacuumed and refrigeration performed on the line-set ?

Ken ICE-Ashbrook

Are the compressors pre-charged too? Seems like there would be a small vacancy in it to be evacuated? Thanks for great product.

Sebastian

I need a system for 3 small room to install myself. Can you do a diy condenser connected to 3 rooms?

michael meglen

Are there any diy for a 2 room system

Mike

What if I need like 35 feet to go from a room over garage to condenser can I get a longer line?

Larry Ethell

My MrCool was supposed to have precharged lines. It stars right on the unit lines must be evacuated. I know the system is charged but I thought the lines already had a vacuum on them. I just purchased it from you 2 wks ago.

Alex

Is an ISO licence required in Ontario to buy or sell a Mr Cool with precharged lineset?

Adam

Can you connect two precharged line sets together? My current installed mini split is a 9k BTU Sanyo with flare nuts on the line set the length is right at 35'...If I buy a 12K BTU 115V Mr. Cool DIY with an additional line set will the line sets connect together?IE are the connections male female on the line sets?

Jerry

I am installing an 18k DIY Mr. Cool and the linear distance from the indoor unit to the compressor is approximately 12 feet. The line set has a fixed length of 25 feet. What Is the best method to coil the extra 13 feet of length? Can I leave in a vertical coil? But if I do won't the refrigerant oil get trapped in each coil? Should I mount to the exterior wall bending the line horizontally for 4 feet (with a slight down grade) bend down vertical for a foot and then bend again horizontally back to the compressor? And lastly should the entire line set be higher than where it ties into the fitting on the compressor? Thanks for getting back to me.

Joe Osgood

Can these lines be disconnected without losing the charge? Example. To move the condenser for service.

Rachel

Can I connect the pre charged line set and let it sit for a week while I wait for the electrician to come connect the power? Or do I need to operate the system immediately after hooking up the lines???

Paul C.

Which HVAC companies ( ie. Goodman, Bryant, etc.) use precharge fittings on their equipment that will accept MRCOOL lines ?

Dave Licciardi

I am installing a 24k diy kit and don’t have access to go directly out the back of the unit. There is a knockout at the side. I need to run the lines thru this knockout and then 90 degree bend the line set out the wall. Should I have any concerns bending a precharged lineset?

ted siewko

I'am going to purchase a 36K BTU mr cool DIY 2 ZONE 2 - 18K Air Handlers Split System. Would 16 foot line sets be sufficient enough for the 36 K BTU Condenser ? 25 foot line sets would be to long.

Nick

I have a precharged mini split would i connect the lines like any other unit?

Jeff

Is it possible to move mr. Cool DIY unit after installation? Can the precharged lines be closed or does the refrigerant need to be evacuated prior to disconnecting the mr. Cool DIY precharged lines for moving of the unit.

Darrow C

After 5 years of use of a system, if I want to test the system for any refrigerant leaks, are pre-charged line sets more or less difficult to test for leaks compared to sweat line sets?