The Line Set For My AC Or Mini Split Is Too Long!

When your AC line set is to long you do have options. I’ll discuss them here using as much priority as I can muster.

Check with technical support for the particular manufacturer and model number your concerned about. I’ve collected a few tech support numbers for your convenience. Ask them what the minimum and maximum line set length is for your equipment and if you can have it coiled up behind the unit.

I remember one particular brand that allowed a minimum line set length of seven feet man other are around ten feet. One tech support said that if the line set was any shorter than what they spec then the unit would tend to vibrate or be noisy. So once you know the minimum length then shortening your mini split line set is okay to what ever length your manufacturer says.

What To Do With Excess Line Set

Not all installations are the same. If your outdoor unit and your indoor head are directly opposite each other on an outside wall then one option is to coil the line set and hide it behind the outdoor unit.

Leaving a coiled up line set behind the unit raises a lot of controversy amongst HVAC technicians because the loops, in a vertical position create traps for oil to accumulate inside the lines.

An incomplete install just to show the idea of looping line sets behind outdoor units. It looked better when done. When it’s behind a barn who cares.

These traps are restrictions to the flow of Freon. The correct name for Freon is refrigerant because Freon is a brand name. Regardless, it’s just a gas that the compressor pumps refrigerant through the system. That gas moves oil from the compressor through the system also.

That oil can lay at the bottom inside of each loop creating a restriction or a trap like the trap under your kitchen sink. There have been a lot of installs done with the line set looped behind the outdoor unit. I’m not advocating it. Just sayin.

It sort of depends on the velocity of the refrigerant flowing through the line. The oil will accumulate at the bottom of the loops and then as it begins to plug the line until the velocity of the gas flushes it out and the cycle begins all over again. The oil keeps going back to the compressor.

With too many traps or maybe even one large trap (don’t know) it will rob the compressor of oil and the compressor will eventually die.

Another thing you can do, only if your line set is running horizonal for a spell, like in a crawl, basement or an attic, is to tip or turn the coil horizontal. No traps are likely to be created with horizontal loops. You just have kind of look at the line and think to yourself, could that be a trap?

One more idea is to move the outdoor unit away from the indoor head and the install some nice line set covers to make it more attractive.

Do I Need To Remove Refrigerant If I Cut My Line Set

It depends on the length of line set you bought. This is a great question for tech support or you can reference the installation instructions. Usually there is a base length, lets say like 25′ that the manufacturers will say, the unit is charged for a 25′ line set. So if your line set is under 25′ then remove so much gas and visa versa if your line set is over 25′.

The amount of refrigerant in your unit greatly impacts the efficiency of the system and it’s overall good health.

Chad Peterson

Chad Peterson is near 40 year veteran of the HVAC industry. "I like to explain heating and air conditioning problems in a way the average home owner can understand. "

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