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Mini split line set question

Posted by ylmzm (My Page) on
Fri, Feb 28, 14 at 16:04

I need to install a line set from an outdoor unit to indoor units (R410A refrigerant will be used). I found ready-to-install line sets sold online (3/8" and 5/8"). These line sets seem to come in lengths of 25' and 50' and there are already flared ends on them. They are also insulated. Example:

The problem is that these are not optimal lengths for my application. They are also expensive. I wonder whether the following is acceptable: Use a refrigeration coil, cut in length, flare the ends, and then insulate with rubber, self-adhesive insulation. I think I can use regular refrigeration coils (ACR copper coils).

Coil example:

Insulation example:

Is there anything about these ready line sets that justify the use of them vs preparing your own ? (except being faster to install)

Follow-Up Postings:

RE: Mini split line set question

"Is there anything about these ready line sets that justify the use of them vs preparing your own ? (except being faster to install) "

Some will argue the ready mades are cleaner but I say that depends on how well the tech takes care of his coils. Some say the unit is precharged with exact amount of R410 nessary for the ready made linght but how can that be true if various lengihts are available? No way I will pay what they want for premade sets. Besides,who wants the excess taking room in the attic?

RE: Mini split line set question


RE: Mini split line set question

You can certainly make your own line sets. I would only do it with new clean tubing. I always cut the factory made flares off anyway. You do not say how long your line set is going to be. I guess I'd try pricing at every supply house in town to see who will give you the best price. You will want a set of spring benders to form the tubing. Soft copper work hardens in a hurry and at the worst possible spot(s). Also, be careful with the insulation. If it is not well done and covers completely you can end up with sweating lines that drip and can make a heck of a mess over time. Read that, MOLD.

While I understand the desire to save money on your install, I will say that you want to do this install once. Mini-splits are really reliable when installed properly. but they can be a bear when something in the install isn't right.

Make sure you use exactly the line sets diameter specified by the manuf. Manuf are very particular about that spec.

RE: Mini split line set question

Thanks, Jackfre. I will use new ACR tubing (1/4", 3/8", and 5/8"). Some sections need to be 5/8" & 3/8", some sections are 3/8" & 1/4".

There are various lengths from outdoor unit to branch box and branch box to indoor air handlers. (For example: 17', 20', 40', 19' etc.)

You were very helpful earlier and answered one of my questions about Fujitsu HFI mini split system with AOU48RLXFZ. This question is also related to the same system.

I cannot find a rubber insulation for 1/4" OD tube, the smallest size insulation I can find is 3/8" OD (Armaflex brand). Can I use 3/8 insulation for 1/4" tube ?

Thanks for warning about the seating risk if insulation is not done correctly. How do you connect two 6ft length insulations? Do you use a special glue at the joint, or using an line set tape is enough?

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