One of the biggest challenges to installing a mini-split is getting the line-set flares together correctly.
The connections need to be sealed good for the system to work properly.
Often, many DIY mini-split kits will come already with flared ends but sometimes these flares will need to be redone.
If the tip becomes scratched or over-tightened striping the bolt it will need a new flare.
Flaring the line-set is not difficult with the right tools with some tips below to help get it right.
What is a Mini Split Line Set?
A mini-split line-set is two copper tubes that transfer refrigerant between the indoor unit and outdoor condenser.
The line-set has flared ends which are bolted together making an airtight seal.
After bolting the line-set together it needs to be placed into a vacuum which holds and does not leak.
Once the system is tested for any leaks the refrigerant is let into the system.
8 Reasons Why A Mini Split Line Set Flare Will Leak Refrigerant
- Flare Is Not Big Enough
- Over Tightening the Flare Connection
- Scratched and Scarring
- Put Oil or Thread Sealer on the Tip
- Incorrect Flare Nut
- The Flare as a Scratch on It
- The Inside of the Tube Should be Round
- Connections Not Tight Enough
If the threads are striped they will need to be flared again with new connections.
The best way to stop any over-tightening is to use a torque wrench.
Example Line-set Torque Wrench on Amazon
YELLOW JACKET 60652 Eight Head Torque Wrench Kit
Oil is often added to the tip of the flare tool so there is less friction and a smooth flare surface can be created.
Example Nylog on Amazon
Refrigeration Technologies RT201B Nylog Gasket/Thread Sealant
Often, a flare nut that is bad or lost is replaced with a nut that will screw together but not made for high-pressure.
High-pressure fittings have more surface area and are thicker compared to other nuts.
For example, moving it around a concrete slab can mark up the tips sometimes.
Be careful when moving them around and be sure the flare tool tip has no scratches.
It should be round with no damage. Often a reaming tool is used to make the tube into the right shape.
Using a torque wrench will give the right amount of tightness needed.
The manual will have the torque amount needed for each system.
Getting a line-set to bolt together properly requires a good flare.
Sometimes it can take a bit of practice to get w nice flare but it is not too difficult.
Luckily if a flare is bad only a small amount of the line-set needs to be cut for a new flare.
Using good tools can make a big difference in how a flare comes out.
Also, using a good sealant can make a big difference.
If no sealant is available refrigerant oil is often used to help everything go together and seal properly.