View Full Version : LIQUID LINE
12-02-2006, 10:49 AM
I'm in the middle of a second floor addition and want to run a line-set for future air conditioning. I'm going to run the line-set within the walls from the attic to the first floor. My question is when the system is installed if the future will the liquid line cause condensation within the wall since it is not insulated? When I purchased the line-set I was told not to insulate the liquid line because it will affect performance on a typical split system.
Please advise so I can run the line set and close up my walls.
12-02-2006, 10:53 AM
The LL is not commonly insulated ,however i have heard of some guys doing it in extreme conditions.
12-02-2006, 10:59 AM
Originally posted by zoom38
I'm going to run the line-set within the walls from the attic to the first floor.
This is the norm in Texas and I thought it was everywhere how else would you run them from an attic?
12-02-2006, 11:04 AM
Finest, if it is common that the liquid line is not insulated then is it a given that the line will not condensate within the wall?
MrBill, in my area it is quite common for the line-set to be run down the outside of the wall and not within the wall as I am going to do.
12-02-2006, 11:36 AM
hey zoom dude that a fast name.
anyway dude run the lines inside pvc pipe.
protect them from small nails, and in future lines can be replace without a problem.
make sure both ends of pvc pipe are cover/seal
and yes dude don't insulate the Liq.line
at lease not in the south.
yes the suction line has to be insutated.
if going to use pvc
the pvc pipe large enough for both lines in the pipe
and use 45 ell not 90
and seal the ends pvc cap or foam-o-fill what ever.
on a 2x4 should work but i don't think you need it,
pvc that is.
[Edited by fix_it_dude on 12-03-2006 at 12:57 AM]
12-02-2006, 11:36 AM
There are no givens or guarentees, there are conditions (usually service related ) that a LL can sweat or that extreme conditions can warrent the LL being insulated, i suggest having a profesional outfit do the work for you.
12-02-2006, 11:47 AM
Thanks guys for your thoughts.
Dude I will give the pvc conduit some thought, don't know if its possible with a 2x4 wall.
Finest, I don't know a professional who would come out to just run a lineset. I can't afford to have the AC system installed yet thats why im just running the line-set for the future.
12-02-2006, 07:15 PM
Line sets are fine in floors / walls. You'll never have an issue with a liquid line.... but you could have an issue w/ the suction line. If you read the specs, there are conditions that could allow the insulation to sweat IF there is not sufficient air for evaporation - the way to compensate for this condition is use the right wall thickness IE: use 3/4" not 1/2". Protecting the line set from future nails etc is common sense. Also a word to the wise would be to run more control conductors than you need for future issues.
Pls call a contractor -- yes it'll be a few bucks, but at least it's done right B4 the walls go up.
12-03-2006, 09:13 AM
How do you know what size lines to run?
12-03-2006, 09:16 AM
Originally posted by billva
How do you know what size lines to run? :)
I was thinking the same thing as I read this thread.
Inside a wall or floor, I would insulate a LL along with the SL. I have installed too many split systems(HP's and straight air) that have had high frequency vibration going thru the lineset. Once it's in a closed up wall/floor, it's too late. I believe you can get armorflex insulation down to pretty small I.D. sizes with small O.D. as well. We had one customer that complained and we were back on that job too many times which destroyed any profit we had made. Just my 2 cents.
12-03-2006, 11:43 AM
Billva & Jrbenny, with the heat gain calculation using HVAC-Calc I came up with 3 ton. In reading up on it and talking to others I'm running 7/8, 3/8.
DNA, I don't mind insulating the LL but will there be an affect in performance as I was told by another in the business?
Insulating the LL will not diminish performace. When its time to have your A/C system installed, be sure to have a professional contracting company install it. Ask for references and check them out. Any reputable dealer will not have a problem providing them.
12-03-2006, 03:04 PM
I agree with dna. My first custom home had a slight gurgling noise in my master bedroom wall. I only heard them on A/C start-up and shutdown. Noise was from the liquid line. My current home has insulated liquid lines and I can't hear them. Liquid lines are "almost" always warmer than outside ambient, so the liquid line will not absorb heat unless the line set space is very hot. Warm LL's are left uninsulated to give off heat, hence marginally increase capacity. Although, contractors in Phoenix don't even insulate LL's when they are run in the hot attics. Whatever you choose, insulation cost or performance will not be an issue. Sound abatement could be important.
You say a contractor won't install the line set only. You may consider paying for a service call. The tech could elavuate the install, size the line set(we are not allowed), and give you some helpful hints or cautions. Once the walls are up, it's too late.
12-03-2006, 05:54 PM
We do a lot of splits and run line sets in vinyl down spouts like this.
12-03-2006, 11:39 PM
Wally, I have seen the downspouts used as a conduit on the outside and have found slimduct on the net but I don't like the look thats why I decided to run the line-set down the inside of the wall.
Thank you all for your insight it has been a great help.
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