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What are the Line Set Length Limits for the 27K and 36K Multi-Zone DIY? - Ask the Expert Episode 237
Today's question comes from Charles Dart. "Hey Dan! What are the line set length limits on the MrCool 27K and 36K Multi-Zone DIY systems?"
On any mini split you have got refrigerant lines that connect to the inside air handler and they go outside to the outside condenser. So, there is a maximum length that line can be. A compressor can't push refrigerant like a mile. That would be impossible.
So, every condenser and air handler, whether it's multi-zone or single zone, is going to have a limit.
For the 27K, the total line set length can't be more than 197 feet, which is really far. So, you should be good. However, you can't have a single line set more than 75 feet between each air handler and the condenser. If you need more than that, you're going to have to do something else or move your condenser.
For the 36K, the total line set length can't be more than 262 and the single line set length between each air handler and the condenser can't be more than 75 feet again.
If you have any more questions, please, just ask in the comments below.
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When it comes to positioning the condenser unit, I have seen allot installed parallel to the structure. My thought is that this would restrict air flow and efficiency. What do you think?
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So long as the condenser is installed with the clearances required in the manual, it will be fine.
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I want to install a Mr. Cool 24k or 36k unit in my detached garage. The ceiling is not insulated and living in Southern California, the radiant heat from the roof make this space quite hot. We have to keep the open rafters in the garage. The garage is about 800 square feet.
The inside unit needs to be installed on an interior wall. So my question is, can i run the line sets through the interior wall then horizontally to get the lines outside? My concern is the drain connection. Assuming I can keep the drain connection sealed and at a sloping angle, I believe the horizontal run out side should be ok.
Please let me know the limitations I have with DIY and running the line sets.
Thank you!
Robert
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Hi Robert,
You can essentially run the lines however you need, and if necessary, you can run the drain line separately to ensure that it slopes downward. You can also get a condensate pump if the drain line can't be sloped downward, as well. Please give us a call at 270-575-9595 if you need further assistance when installing.
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I loved the video and your sense of humor :) Living in Nova Scotia so the winter heating function is waaayyyyy more important than the summer cooling. Considering installing a single 'air handler' mini split due to oil costs. The suggested one is 18K btu but the optimum place to put the condenser will need about 50 feet of line set. The line will have to go down a couple of feet and then run laterally for about 40 feet and then go vertical up about 7 feet. I have read that 4 els ( 90 degree bends) will count as about 4 feet. So guessing the compressor will have to do the work of 50 feet of line. The technician says it will be fine however....I have done more research online and there is talk about the diameter of the line being bigger or smaller depending on the length of the line. Any wisdom to share please.
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Depending on what mini-split you're considering, it should designate its line set limits in its manual. It can vary depending on what system you get, and especially so if you're considering a multi-zone system, but the typical line set length limit for a MrCool single zone DIY Ductless Mini-Split is 75 feet.
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A Lenox unit three air handlers, the distance of 1 is 50 ft. The second is 60 and the 3rd is 75 ft . The 50 and 60 are 9000 and the handler at 75 ft is 12,000. Do you see a problem with this.
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There should be guidance in the manual regarding line set lengths. We cannot say whether or not this exceeds the limits set by Lennox, as we are unfamiliar with what specific product you are talking about, and we only sell furnaces and boilers by Lennox.
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dan ,the man, I have a 2 mxs 36 ductless by daikin. the issue is 1 of the lines is over the 82 ft single line max (15ft) .Question is. can I run a larger refrigerant line to a manifold. and connect both indoors at 50 ft? I am open to any other suggestions that would work at this length. Mick
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Since it is a different brand than what is discussed in this video, it's possible that the limit is different. It is unlikely that you would be able to join then split the refrigerant flow, though. While you could technically exceed the limit, you would lose efficiency.
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I have a Mr Cool 36K 4 zone unit and need to install 2 zones at 50’ and one at 25’ for a total of 125’. I got everything run and when I removed the cover panel on the condenser the was a label stating total line set length max was 98.42’. I guess 262 is no longer an accurate max length?
Do you have any suggestions should try to change things around?
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I know you mentioned the 65ft limit for 12k handler to the condenser. Does it affect heating and cooling both or only cooling. Does it also mean that 65 ft will be less efficient than one at 50 ft. Does it just impact the start or even during a run. I have one handler at 35 ft and one right after that at 79 ft. What are my options
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The limit is 75 feet. Going beyond this would affect overall performance, so it would affect both heating and cooling. If the line set is within the limit, it won't necessarily affect efficiency levels. It is recommended that you move one of your air handlers closer if possible so that you do not go beyond the limit of 75'.
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I want to install a 3 zone Mitsubishi mini split for 3 additions to my residence Two of them have very short line runs - 10 to 20 feet each. The third is much longer. It needs to cross the main house in the attic to get to the small room on the other side of the house. The distance is 95 to 120 feet. Will it work efficiently? Do i need to add feet to cover each elbow? any suggestions for how to HVAC the area - a room 11 X 12.
Thank you.
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For Mitsubishi systems, it depends on the size of the air handlers. The 6k, 9k, and 12k air handlers have a maximum piping limit of 65'. The 15k and 18k air handlers have a maximum line limit of 100 feet.
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Very helpful video. Do you all know of or sell a mini split unit where a single line between the handler and condenser can be longer than 75ft? Ideally in the 160ft range.
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That length may be unlikely for a mini-split, but it can also depend on the size of the mini-split itself. You'll be able to find the ductless mini-splits that we have at https://iwae.com/shop/heating-air-conditioning/full-systems/ductless-split-systems/.
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What's the maximum line length for this unit?
MRCOOL DIY Gen-3 12,000 BTU 22 SEER ENERGY STAR Ductless Mini Split Air Conditioner & Heat Pump w/ 25 ft. Install Kit 115-Volt
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The maximum line set length for that system is 75'.
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I installed a 36k in December,
With 18k,9k,9k,9k inside.
In heat mode it keeps going into defrost every 30min and not putting out very hot air 110° if I set the 18k+2x9k's at max temp. And it goes for hours before a defrost.
I installed with 214' total length. mix of 4x16's & 6x25's
41' to the 18k
50', 57', 66' for the 9k's
Is it possible that the refrigerant levels need adjustment?
I found no leaks in all of the installation checks and the behavior has never changed/degraded further.
It seems to be performing well in cooling mode now that it's warming up a little outside.
However, heat mode never worked correctly as I could only get it to warm up the main room to temp by running extra units in the bedrooms.
Are the pre charged line sets under charged to allow for the "standard" charge to not overcharge the system?
is the standard charge modified on the outdoor units to account for the pre-charged linesets?
Thanks,
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Please give us a call at 270-575-9595.
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Hey Dan,
You mentioned max. lengths in your videos, what about minimum length? for 30 k Fujitsu mini split, single.. manual states 17 ft. Kit purchased was 15 ft . Should I run the extra line horizontal or vertical to the outdoor unit.
Thanks,
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We would recommend going by what the manual says. Minimum lengths are different between different brands, but if the manual says 17' minimum, we would recommend that. Excess line should be stored horizontally near the condenser.
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We have a quad system, one of the units has to run 95 feet. Is it going to be that big of an issue to run it 95 Feet (36K overall, indoor 12k). Will the unit just not work?
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It would work, but it would be less efficient and it could potentially affect how well the unit functions.
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I’m looking at purchasing a 3 zone 36,000 btu unit. It asks what line length I would like, if I choose 50ft will it come with 3 50?
Does it include the 3 lines?
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All of the DIY multi-zone systems come with one 25' pre-charged line set per air handler. Most mini-splits that are not DIY do not come with a line set. It may vary depending on retailers.
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Thank you, Dan!
Chuck
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I need to extend one line by 25ft and another by 10 ft. I am confused as to what kind of couplers I should use. I have come across 2 types. One has the shape to fit the flare of the line set the other is just a tube with threads on both ends but has a metal piece inside. Which can I use and which is best. Thanks
John
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We sell only one kind of coupler kit for the DIY. You can find an example of that here: https://iwae.com/shop/mrcool-diy-line-set-coupler-kit-for-9k-12k-18k-line-set-ha21479.html
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Hello,
Just curious if maximum line set lengths must include supply + return length or do we only count the length of the supply and return once together?
Thanks for your advice
- John
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The maximum length relates to the distance between an air handler and the condenser specifically.
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On a dual zone DIY Mr. Cool 27k unit with a 18k + 9k head I want to order a line set of 16' to connect 9k and 25' to 18k but i need an extra 16' to add to the 25' with coupler to 18k head. Do I need to add more refrigerant because of adding the 16' lineset to the 25' second zone? Also when the instructions say to coil extra near condenser, Why? I'm looking to coil extra lineset in attic/insulated of course to make the connections cleaner at the condenser unit. and not coiled behind or serpentine in attic to eliminate coils all together. Can this be done?
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You would not need to add refrigerant, since all the DIY lines have their own refrigerant. It should be fine to keep the extra coil in the attic.
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I bought a 4 zone mini split with two line set extensions to give me 2x 50' runs and 2x 25' runs. Is there a recommended order for attaching them to the condenser? Currently i have the longest two at the bottom in slots 3 and 4 and my short run handler (#1) is not cooling properly if any of the others are off, or #4 isn't max cooling its area.
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The largest capacity air handler should be connected to zone A. The others can be connected to whichever port works best. The wiring must be connected to the correct block on the outdoor unit matching the refrigerant lines. If you have excess refrigerant line, it may be necessary to add refrigerant to the system. If some units are not working properly and all the electrical, valves, and fittings have been checked and are correct, open, and tight, then a tech with gauges would be needed to see for sure.
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What is the meaning of a maximum lateral length of 33 feet between highest and lowest unit? I want to install 3 units from one cendensor, where our max distance between them is 39 feet. Is this ok?
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As long as the highest indoor unit is not more that 33 ft above the lowest indoor unit, you will be fine. The 39 ft between units is fine as long as the elevation is OK.
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What is the shortest I can cut a line set for a AIRETEMP minisplit?
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I'm not familiar with that brand, so I couldn't say. However, they should detail that in the installation manual in the section on refrigerant.
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Bought a 27 K condenser with 2- 9K ac, in the future I will add a 12k Ac.
My question is:
Can I shorten my refigerant to 8 ft ?
the other will be at 12 Fl ,
and the future line at 75 fl .
Please advice .
Thanks
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The DIY lines are not designed to shortened. They can be lengthened through the use of a coupler kit. We would not recommend cutting a DIY line to shorten it.
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can i order a 24k 20 seer unit with a 16 foot lineset .also, if you roll the excess lineset should it be horisznal or vertical?
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You can get a 16' line set for the MrCool DIY products. The manual recommends you keep the excess coiled and stored near the condenser. It doesn't actually specify horizontal or vertical.
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What length of line are the units rated for? If I were to install a 12k unit myself can I use a 25' lineset using just the precharge? In other words, without adding refrigerant?
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Yes, you could use a 25' line with the DIY 12k. They lines themselves are precharged for the DIY units.
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Can more than one inside air unit be on the same line?
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No, each would need its own line.
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What's the minimum length you can have on the line set of a 12k Mr. Cool unit?
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If you're asking about a DIY system, the shortest line set available is 16'.
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One other note, Dan. I go by Chuck and I do play darts. For years we had a competitive team called......
Chuck Dart and the Dart Chuckers
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