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Can I Install the Air Handlers at Different Times for Multi-Zone Mini Splits? - Ask the Expert Episode 213

"Hey Dan, for multi-zone mini splits, like the dual-zone system, do you need to install both zones at the same time or can you install it and use one zone, then install the second zone a few weeks later?" Yes. You can do that for some multi-zone mini splits. You will want to check with the specific model because some of them you can do that with. For instance, the MrCool Multi-Zone 36K BTU you can start with a 9k air handler, then add a 12k air handler, then another 9k air handler, etc. There will be a specific order, though. You wouldn't be able to just add whatever air handlers you want, but yes, you can start with one zone and install the rest later on multi-zone mini splits. Multi-Zone mini splits do allow for installing and using only a portion of the air handlers they are built for. For a more thorough answer to your specific setup, you can always give us a call and our team of experts can help you. Have more questions? Just ask them in the comments below or on Facebook or on Twitter.

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Glenn

Hello, I would like to add a third indoor head to an existing system. What would the process be?

Amay

I have a mini split multizone system with 5 zones and I have hooked up three zones. I want to add refrigerant (EPA certified)? I have individual ports for each zone and also have a king valve... Which port shall I use (a) zone port (b) king valve

Matt

I’m adding a 3rd 9k head to a 36k mr cool that is already running two heads. For installing do I need to : 1.) turn off unit 2.) close king valve 3.) add line set 4.) open new line set valves + king vales similar to original startup? the pre-opened king valve is throwing me for a loop

Doug Morrisey

I have a MrCool DIY 36k outdoor unit, (1) 18k handler, and (2) 9k handlers. Is it OK if I install the 9k handler on Port A of the condenser, and 18k on Port B, and last 9k on port C of the outdoor unit? I know the 18k is supposed to be on Port A, but will the unit operate correctly this way?

Sebastian

Hey Kyle, I’m installing a Gen4 MrCool Multizone system I have 12 + 9 + 9 + 9 heads and a 36k unit. I want to start with the 12 and one of the 9k heads but am questioning the order of operations for adding additional heads after getting the unit up and running. What steps need to be taken before adding the additional two 9K units? I know we need to cut power to the outdoor unit, but should i also close the king valves before adding the line set? are the steps below correct? 1. Cut power to outdoor unit 2. close king valves 3. attach additional line sets 4. open respective valves for new line set 5. open king valve 6. restore power

Jason

Hello, I have a MrCool 27k multizone with 18k and 9k. 18k is connected to port C and 9k is connected to port B. Nothing is connected to port A at this time. Will this be ok?

Tyler

I have a 27k condenser with a 12k and a 9k wall unit attached. Can I run the 12k unit while the 9k unit is off/not running? What about the 9k unit while the 12k one is off/not running?

I have a TOSOT 12,000 BTU mini-split 115V, and was wondering if I could convert it into a dual zone? This will be for around 900sqft home. After some googling I've found mixed results. What do you suggest?

Christi

If I were to install a Mr. Cool DIY 18000 BTU dual zone mini split. Could I install and use one 9K air handler for a few weeks before installing the second 9K air handler?

Ron hurlbert

Hi Dan, wanted to get your thoughts on this. I have a 18,000 btu multi zone heat pump that was given to me, ( Fujitsu AOU18RLXFZ ). The plan was to put one 15000 btu head in the great room, but the installation manual says 2 heads are required to operate the unit. That does not make sense to me. Thank you in advance for your input

Mike

Thanks for the info! Does the same apply to LG units? I have a multi zone 15+9+7 and 24k condenser. I should be ok to just install and run the 15k for now?

Jim

I have a 600 sq ft, 10 ft ceiling space that Has 4 separate zones in need to temp control. In large the spaces would have the same temps and usage. The smallest 4 zone I have found is 30k btu and I’m concerned that would be way oversized, is there a way to make a smaller unit work? Like a 24k three zone somehow split one of those zones for 2? Or get the 30k and somehow throttle back the usage? Any recommendations?

Peter Pham

Hi Dan, I have a multizone (4) LG 36k.Technician installed 2 12k for me couple years ago. I think it's pretty simple to install per DIY instruction. So I tent to install the third one 12k but When I open the panel I saw only one core valve for gas and one core valve for liquid. Is that means I have to close botH valves before vacuum the newly installed? Thank you very much. Peter Pham

Dave

Can I use zone b and c skipping a on a lg mini trizone

Steve brown

Do you need to close the king valves before you add another line set the open the king valves last ?

I have two 4-zone MrCool DIYs on order and will want to phase in the installation. What constraints will there be for the order in which we install wall units? One is supplying 4 9k units all on the same level. The other is supplying 3 9k units on one floor and 1 12k two floors below.

Yuan Tu

Dan, I have a 3 zone Gree Mini split AC that is leaking coolant for the 2nd time, I am afraid that one of the air handler has an internal leak. I am thinking about closing one zone pipes to isolate the problem, or it could be just downgraded to 2 zones and use it this summer. Can this be done as you mentioned with MrCool Multi-Zone 36K? Thank you for help in advance! Yuan

I have a aou18rlxfz (fujitsu). I'm running a 1200btu and 9000btu head units. When both units are on I get cold air, however if I am only using one unit at a time it seems like the fan is on instead of the A/C (69 to 70) degrees. My installer is having a hard time figuring out the issue. Your thoughts?

Cory

As stated below in a previous question, I have a 27K unit with 9K AH (port A), 18K AH (port B), and 9K AH (port C). About half of the time the large unit will not blow cool air when it should be, but when it does it works great. Is this possibly from not having the largest unit connected to port A? If so, the manual says I will void the warranty if I remove those connections from the outside unit. How do I get around this?

Yanto

Hi Kyle, If I have a 30k compressor with 9k+9k+12k configuration, I understand that I need at least two condenser units hooked up, but does it also mean that I need to have at least two condenser turned on at any given time? Can I just have one condenser turned on, even through they are all hooked up?

Joe noworyta

I just installed a 36k mr cool multi zone diy with a 36k head on the a terminal and the A refrigerant lineset port. I turned it on and it runs for about 5-10 minutes (does not cool or heat) then throws a P6 error code(discharge temp sensor).any ideas of why it does? I called tech support a few times and can never get in touch with someone.

Roy

I have a MrCool multi zone mini split unit it is 36,000 BTU. I have 1 18k air handler and 2 9k air handlers. Can I install just the 18k air handler for now and add the two 9k air handlers in a few days?

Edward Yeakel

I am looking to buy a MrCool DIY 27k dual zone with with a 18k and 12k air handlers. What happens if I run both handlers at the same time? What happens if the air handlers are trying to pull more btu than the pump produces? Thank you!

Adam Abelha

I am confused. In the video you say, YES, YOU CAN RUN THE UNIT WITH 1 HANDLER ATTACHED. Then yoi go yes and no throughout the q&a below. So please let meask for minor specifically. I have a 27k Mr Cool condenser and 2 12k but air handlers. Can I run on just 1 - 12k air handler ( that is only 44% capacity) or do I need both 12k units installed ?

Colby Barron

I have just received two 27k multi-zone DIY systems. The first one has 3 air handlers (18k/12k/9k). The second has two air handlers (12k/9k). I'm waiting on line set extensions to install the complete systems. On the first one, can I operate it with only the 18k air handler connected (to port A)? The same question for the second system with the 12k air handler. Thanks!

Cory

I have a DIY multi-zone with a 27K condensor, 9K,9K,18K air handlers. I have a 9K air handler on port A and the 18K air handler on port B and haven't connected the 3rd air handler. Is this going to be a problem?

Timothy

I have a 36K condenser, with 9+9+9+12 air handlers. I installed the first 9K on port A. Is this a problem? Can I just put the 12K on port B?

Eric Swartz

For this system 36k BTU 21.5 SEER Multi-Zone MrCool DIY 4 Zone Ductless Heat Pump Split System - 9k+9k+12k+12k, If I were to start with one air handler I would put the first 12K unit into port A correct? Also the breaker should be 30amp with 10awg?

Charles Dart

I have the DIY/Gen3 multi-zone, 27k condenser (2 air handlers:18k,9k). One of them requires a left side hole for the lines. Figure 4.4 in the installation manual shows the line at a horizontal angle (versus right side straight out 90 degrees with slight drop). I'm assuming this is to prevent a kink. The cut will be a bit tricky. If the wall is zero degrees and the right side exits at 90, what is the optimal horizontal angle for a left hole? You can email me with the answer. Thanks

Anderson Clark

I'm waiting for arrival of DIY/Gen3 multi-zone, 27k condenser (3 air handlers:9,9,12) in package HA 21036. I need one 9k a.s.a.p. If I reserve Port A for the 12k linseed, can I use Port B for a 9k AH immediately and run other two line sets a bit later?. . . . I am going to need to knock holes thru brick for 3 line sets. Alternatively, I can run all 3 linsets through one large brick opening into basement and continue line sets at joist level and up through floors to each indoor unit. Theoretically, is that a problem?