Rough in line set for future use

[NeubCont]

Currently under a renovation project of two story dwelling
Based on budget constraints
While the 1st floor ceiling is open and a front room needing a head unit
The line set would run front to back through the 1st floor ceiling joists.
The outdoor unit will be located in the rear of the house
Want to rough in a line set with wire control for future use on mini split.
Can anyone recommend what they would use.
Is there a universal size of the line set and wires for the controller?
Can the line set be precharged or left open to the air for an extended period of time?
Want to install the line set for future use and want to drywall the ceiling closed for cosmetic purposes and have the line set come out of the exterior wall to the main outdoor unit. Would you leave it long or cut it and then braze or couple it in the future?
Thanx for your suggestions and comments in advance

 

[LS6 Tommy]

Sorry, but you can't leave a lineset open for any extended length of time. It needs to be piped in and evacuated ASAP. You're just inviting contamination from corrosion.

Tommy

 

[rlitman]

Sorry, but you can't leave a lineset open for any extended length of time. It needs to be piped in and evacuated ASAP. You're just inviting contamination from corrosion.

Tommy

Leaving it open does sound like an invitation to contamination. What are you thoughts on flaring the ends and installing flare caps?

 

[LS6 Tommy]

Leaving it open does sound like an invitation to contamination. What are you thoughts on flaring the ends and installing flare caps?

I'd sweat in a schrader valve on the end most likely to be cut off, flare and cap the ends and purge dry nitrogen out a loose flare cap and tighten it while purging.

Tommy

 

[BD1]

Tie together the inside lines, add schrader to one line outside, cap the other, and test if there are concealed joints.
If test OK, pull vacuum, and add dry nitrogen .


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[Git]

A little outside of the box....

So it sounds like you want to run the lineset in-between the 2nd floor floor joists and you would have a clear/straight shot from the back of the house?

If that was the case, I would think about getting something like 4" pvc outdoor drain pipe to use as a conduit for the lineset and some regular electrical conduit (3/4") for the control wires. Get the conduit in place and when it comes time to actually install the minisplit, you should be able to easily slide the lineset into the drain pipe, as long as it is a straight shot.

 

[larry_g]

When we remodeled we had the heating/ac company on line early so that when we had the walls open they came in and ran linesets and I assume they capped them. When the inside was finished they came back and installed the head units and charged it up. So maybe contact your hvac contractor and get him in now.

lg
no neat sig line

 

[NeubCont]

Thanks for your replies
I have the concept of the install
As a DYI wanted to order the line set and wire ahead of time.
No idea of which unit I would go with yet.
Was wondering the size lines and what wire to order ahead of time.
Thanx

 

[BD1]

Size of unit , length of run , and diameter of piping all go together. Same for 220 volt power wiring. Unit size must be known for power requirements. Wire size, length, and amps required must be known .


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[Jackfre]

go to the Fujitsu site and download their catalog. They have very detailed specs per model. Prepare to be confused as the catalog is extensive. You need to size the unit and pick the line set/ per manuf per size. My Fujitsu units all wire with 14/3. Don’t forget backing for the mounting plate. I have one evap that is in the wall piped and it was just a giant pitn to properly connect. I would locate the pipe about 1/3 of the width of the mounting bracket from the left. That way you can relieve more of the backing and Sheetrock to lay the piping off for connection and then be able to push it back into the wall to conceal it. Your biggest question mark will be your drain line. You don’t mention it, but you need to give some thought to how it will be run. A poorly drained mini-split is an invitation to your very own Twilight Zone.

 

[yeldogt]

Normally when you are doing a new mini in a project -- the wall mount is installed on a section of drywall large enough to hold the unit and still provide space for the taping and mud to be finished. The lines sets are all set up and caped -- that way when you go to do it the mount and the lines are there.

To do a retrofit ... you would have to figure out what size will be required and lay it out so you can cut into the wall and have it set up.

This is one of mine from a while back ..... A very challenging one. Prior to spray foam

 

[dave*99]

I just did this. Selected a 18K heat pump mini split. Ran the lines, insulated them, brazed them into a loop, evacuated, leak checked, sealed, nitrogen filed, proper cable installed between condensing unit and wall unit. Power to condensing unit ran. Condensate drain line piped into plumbing.

All sized properly to work together. It really helps to select a system and follow the directions as opposed to trying to make a generic rough in. You have a lot less thinking to do and a higher chance of success.

 

[nadogail]

New houses in subdivisions are frequently built AC ready with a line set, power cables and thermostat wires run to the future location of the compressor unit.

The installation of the lineset and power are the hardest part of a retrofit. Do it while it’s cheap

 

[Jim greengo]

New houses in subdivisions are frequently built AC ready with a line set, power cables and thermostat wires run to the future location of the compressor unit.

The installation of the lineset and power are the hardest part of a retrofit. Do it while it’s cheap

What he said.

 

[yeldogt]

With a mini you have to understand how the head lines are attach so they are positioned correctly .... make sure they are sized property.

Drain line must be in place w/ correct slope.


Doing a typical split is easier as the air handler is not exposed ... with a mini it all has to look nice. They also don't have the drain to worry about