Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 05-23-2012, 11:54 AM   #1
Newbie
 
Join Date: May 2012
Location: Orlando
Posts: 7
Share |
Default

Mini-Split lineset insulation


Hello All,
Is it absolutely necessary to insulate each line separately with a mini-split? If the lines are not separately insulated (but insulated together), what affect would this have on the system?

Curious_George is offline   Reply With Quote
Old 05-23-2012, 06:33 PM   #2
Member
 
Join Date: Oct 2009
Location: Nebraska
Posts: 2,362
Default

Mini-Split lineset insulation


The metering device is in the outdoor portion so both lines can sweat so they both need insulated. Not sure why the instructions say not to run the lines together but it does. Always best to follow the instructions.

Marty S. is offline   Reply With Quote
Old 05-23-2012, 06:49 PM   #3
DIY hobbyist
 
Join Date: Mar 2012
Location: South Florida
Posts: 46
Default

Mini-Split lineset insulation


keeps the insulation tight on each line. Any gaps would create puddles.
ggold is offline   Reply With Quote
Old 05-23-2012, 08:05 PM   #4
Newbie
 
Join Date: May 2012
Location: Orlando
Posts: 7
Default

Mini-Split lineset insulation


Well, I guess we'll see what happens... recently I ran my lineset through the attic and I insulated both lines together. I did not feel like paying for a prefabricated extended insulated lineset (50 feet), so I made my own with copper tubing from Home Depot. 50 feet of 1/4" and 3/8" cost me $100, which was bad enough. I ended up cutting the lineset to 45 feet for my application.

Not thinking about the mini-split traditionally having each line insulated separately, I insulated both lines together. I added additional R-410A as indicated in the IM at 0.2oz/ft, which is about 4ozs. The system is running and appears to be Ok. The air temp coming out of the vent on high speed is about 57*F. On low speed it is about 50*F.

These readings are similar to another mini-split I have in my bedroom with a 15 foot lineset.
Curious_George is offline   Reply With Quote
Old 05-23-2012, 08:13 PM   #5
Member
 
Join Date: Nov 2011
Location: Hartfield VA
Posts: 25,732
Default

Mini-Split lineset insulation


Hold on untill one of the real HVAC guys come on.

I have two mini splits and the lines are not insulated together, reason being one lines is cold and one is hot. One in, one out.
joecaption is online now   Reply With Quote
Old 05-23-2012, 08:19 PM   #6
Newbie
 
Join Date: May 2012
Location: Orlando
Posts: 7
Default

Mini-Split lineset insulation


Quote:
Originally Posted by joecaption View Post
Hold on untill one of the real HVAC guys come on.
I am sure to get a firestorm of opinions either way. Unfortunately, people in all trades come in two different groups... those who have been doing the same thing for 30 years and learned something everyday and those who have been doing the same thing for 30 years and not learned anything after the first 2 years.
Curious_George is offline   Reply With Quote
Old 05-23-2012, 08:29 PM   #7
Member
 
Join Date: Nov 2011
Location: Hartfield VA
Posts: 25,732
Default

Mini-Split lineset insulation


And what does the manufactuer say about it?
They have the last word.
joecaption is online now   Reply With Quote
The Following User Says Thank You to joecaption For This Useful Post:
COLDIRON (05-24-2012)
Old 05-23-2012, 08:38 PM   #8
Member
 
Join Date: May 2010
Location: winnipeg manitoba canada
Posts: 779
Default

Mini-Split lineset insulation


the lines must be insulated seperatly....... will it work togehter .... sure .... follow what the install instructions say
carmon is offline   Reply With Quote
Old 05-23-2012, 09:09 PM   #9
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,486
Default

Mini-Split lineset insulation


What did you put between the lines so they don't rub together, and rub a hole in one or the other.
beenthere is offline   Reply With Quote
The Following User Says Thank You to beenthere For This Useful Post:
hvactech126 (05-23-2012)
Old 05-24-2012, 08:48 AM   #10
Newbie
 
Join Date: May 2012
Location: Orlando
Posts: 7
Default

Mini-Split lineset insulation


Quote:
Originally Posted by joecaption View Post
And what does the manufactuer say about it?
They have the last word.
I emailed Fujitsu and they actually replied... the "application guy" said it should be "Ok".
Curious_George is offline   Reply With Quote
Old 05-24-2012, 08:55 AM   #11
Newbie
 
Join Date: May 2012
Location: Orlando
Posts: 7
Default

Mini-Split lineset insulation


Quote:
Originally Posted by beenthere View Post
What did you put between the lines so they don't rub together, and rub a hole in one or the other.
Before I insulated the lines, I taped them together every 4 or 5 feet, so I could easily slide the insulation over the lineset. I used the Armacell Polyethylene foam (solid one piece, not split down the middle) from Home Depot and "glued" the pieces together with the recommended cement. Worked great and smelled good too.

The 1/4" and 3/8" lines fit nice and snug in there.
Curious_George is offline   Reply With Quote
Old 05-24-2012, 10:28 AM   #12
Member
 
Join Date: Oct 2010
Posts: 260
Default

Mini-Split lineset insulation


Ideally you should separate them, the large line is very cold which must be insulated to avoid condensation or water damage, also, when it goes into the compressor, the cold gas won't work the compressor too hard (or too hot). the small liquid line is at room temp. if it is too cold, it may affect the metering device. But this is all theory, the real effect should be small.

Last edited by clocert; 05-24-2012 at 10:33 AM.
clocert is online now   Reply With Quote
Old 05-24-2012, 10:41 AM   #13
Member
 
Join Date: Oct 2007
Location: Manitoba, Canada
Posts: 326
Default

Mini-Split lineset insulation


There were some manufacturers of ductless splits a few years ago that recommended pairing the lines together and insulating as you have done. I installed a few at that time and they worked fine.

The metering device is at the outlet of the condensing unit, so technically both lines are part of the evaporator. You may loose a bit of capacity, but it has been done before with success.
HVACDave is offline   Reply With Quote
Old 05-24-2012, 10:59 AM   #14
Newbie
 
Join Date: May 2012
Location: Orlando
Posts: 7
Default

Mini-Split lineset insulation


Quote:
Originally Posted by HVACDave View Post
There were some manufacturers of ductless splits a few years ago that recommended pairing the lines together and insulating as you have done. I installed a few at that time and they worked fine.

The metering device is at the outlet of the condensing unit, so technically both lines are part of the evaporator. You may loose a bit of capacity, but it has been done before with success.
Based on the mini-split design, I don't think that having the lines together will affect the performance that much. Will there be an affect? Certainly, but I don't think it will damage or be a detriment to the system as a whole.

There are 3 or 4 thermistors that sense temperature on most mini-split systems. One at the rear of the condenser, one at the inlet to the evaporator, one (sometimes) in the middle of the evaporator and one at the outlet of the evaporator. If the evap inlet sensor detects to high or to low of a refrigerant charge (based on the temperature of the suction line affecting the "smaller" line), the TXV valve will compensate. Once the system is on for awhile, everything should reach an equilibrium.

This is my logic.
Curious_George is offline   Reply With Quote
Old 05-24-2012, 11:08 AM   #15
Newbie
 
Join Date: Mar 2010
Posts: 10
Default

Mini-Split lineset insulation


Quote:
Originally Posted by Curious_George
Well, I guess we'll see what happens... recently I ran my lineset through the attic and I insulated both lines together. I did not feel like paying for a prefabricated extended insulated lineset (50 feet), so I made my own with copper tubing from Home Depot. 50 feet of 1/4" and 3/8" cost me $100, which was bad enough. I ended up cutting the lineset to 45 feet for my application.

Not thinking about the mini-split traditionally having each line insulated separately, I insulated both lines together. I added additional R-410A as indicated in the IM at 0.2oz/ft, which is about 4ozs. The system is running and appears to be Ok. The air temp coming out of the vent on high speed is about 57*F. On low speed it is about 50*F.

These readings are similar to another mini-split I have in my bedroom with a 15 foot lineset.
What type/model mini-split do you have?

205HVAC is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Insulating your attic Bob Mariani How To Guides 5 07-07-2013 08:49 PM
Basement Exterior Above Grade Insulation purpasadu Building & Construction 6 02-28-2012 04:42 PM
LG Mini Split MS 36 AIR CONDITIONER Inlouof HVAC 5 09-17-2011 09:46 AM
Ductless Mini Split Install - need HVAC Tech! mike_30319 HVAC 13 03-30-2011 06:18 AM
Rafter Vents and Insulation nofx1981 Roofing/Siding 15 03-10-2010 08:14 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.