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Questions tagged [mini-split]

A mini-split is a smaller HVAC unit with the blower and control unit inside a room, while the condenser unit sits outside. Use with any relevant tags (i.e. [electrical]). Use for questions about DIY installation of these unit.

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Do I have room to add a 240V breaker in my panel?

I’m trying to see if I have room to add a 240V line for a mini split. The mini split I got is a Gree with nominal 9 amp pull and manufacturer recommended breaker size of 20 amps. Any thoughts on an ...
Chris's user avatar
  • 53
1 vote
1 answer
46 views

Meaning of water droplets symbol on mini split?

Not sure what this symbol means on the right - “water droplets down lines” is the best I can describe it. You can see it on the middle right of the display on page 19 here, but it does not explain it. ...
KaPtain's user avatar
  • 13
1 vote
1 answer
40 views

Suction pipe freezing when blower is on low speed, and runs fine when blower turned to high speed!

I have 12000BTU unit running on R22, and I'm facing a strange issue with my split AC. When I run it with the indoor blower on low speed, the outdoor starts freezing on the suction pipe. But as soon as ...
omsharp's user avatar
  • 111
0 votes
1 answer
311 views

What type of fuse for mini split?

I have a fused disconnect installed for a mini split on a 25A circuit. Should I use a FRN-R or NON 25A fuse? I believe it should be FRN-R since that's for protection of a motor, but looking for an ...
r_alanb's user avatar
  • 215
7 votes
6 answers
2k views

Can I use an overpowered mini split to rapidly cool a space?

I have a garage/gym that I’d like to condition with a minisplit. Since I only use the gym 1 hour a day, I have the idea of cooling it on-demand instead of keeping it at temperature all the time. At ...
zed's user avatar
  • 71
1 vote
1 answer
97 views

Can a mini split handle six air exchanges per hour?

Can an appropriately sized mini split handle 6 Air changes per hour? Our current gas boiler and air handler are failing and so we are looking into replacing the system. We have had a few heating/...
r_alanb's user avatar
  • 215
3 votes
2 answers
187 views

Verify correct disconnect installation for mini split

I am installing a 27K BTU Mr Cool min split (install guide) that requires a disconnect/shutoff. I want to make sure I am correctly wiring the disconnect, as I cannot find a wiring diagram for it and ...
r_alanb's user avatar
  • 215
1 vote
2 answers
169 views

Convert a 240V dryer outlet to go through the exterior wall to an AC Disconnect?

I'm a DIY-er. I have a house built in 1972 with an unused 3-prong dryer outlet (I'm on natural gas now) that's on a 30 amp breaker. I want to remove the outlet and instead run wire from the box ...
Peter Bogdanoff's user avatar
-1 votes
2 answers
68 views

Mini Split with Central AC

Is it possible/efficient to have One mini split unit in the living room and remove all the ducts in that room to then have the central AC only cool bedrooms?
Jona's user avatar
  • 1
0 votes
1 answer
108 views

Can a heat pump designed for mini-split system be used for central AC ductwork?

I am looking at replacing my old central AC unit with a heat pump one using existing ductwork. A contractor quoted me Fujitsu Airstage indoor unit AMUG48LMAS with outdoor unit AOUG48LMAS1. I checked ...
ahala's user avatar
  • 103
1 vote
1 answer
63 views

Should I replace the HVAC or install a mini split in my garage?

I have a detached garage that was built with an HVAC system. Don’t think anything has been updated since the house was built 20 years ago. It was disclosed when I bought the house that it was ...
T Stein's user avatar
  • 11
0 votes
2 answers
159 views

For a HVAC condenser rated for minimum of 26Amp and max fuse 40 AMP what should be the disconnect sizing 30 or 60 AMPs?

For a HVAC mini split condenser rated for 240v and minimum of 26Amp and max fuse 40 AMP what should be the disconnect sizing 30 or 60 AMPs, I am looking to hookup the mrcool 27k condenser which is ...
Shan NP's user avatar
-1 votes
1 answer
99 views

Should I replace an old furnace with a mini split unit? [closed]

I have a very small house that is close to being 700 ft.². I live in the middle of Illinois some winters it gets really cold , many degrees below zero. Last winter I noticed my furnace having a bad ...
Brock Neill's user avatar
5 votes
2 answers
1k views

What should I consider when deciding between a PTAC and a mini-split?

I have built a workshop addition to my garage and both will be insulated. I'm located in Central Indiana, so we get chilly winters (often down to 0°F) and hot, muggy summers (90°F and 80+% humidity). ...
FreeMan's user avatar
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1 vote
3 answers
6k views

Should I use a 15 amp or 20 amp breaker for a mini split with max current at 13.0 Amps?

Installing a garage mini split with AC and heat. Running <25 ft of 12 gauge to disconnect and 10 gauge whip to condenser. Unit specs say rated for 8.7 Amp with max Amps in heat mode at 13.0 ...
KM DIY Home's user avatar
2 votes
0 answers
153 views

Installing a series of FS140 surge protectors to prevent mini split board burnups

I'm having some issues with my current electrical setup. I had an electrician install a 36k Eaton whole house surge protector about a year ago, and the hvac company installed a gree mini split. Since ...
Anthony Ac's user avatar
1 vote
1 answer
795 views

Do I need to vacuum-test the lines for a new mini-split?

Sanity check for installing a multi-zone mini-split system: I pressure test each zone individually. Then I vacuum each zone and release the refrigerant into that line set (assuming no leaks). Then ...
scott's user avatar
  • 21
0 votes
1 answer
56 views

Is there a category of ducted HVAC/IAQ parts but sized for what is typical for ductless systems? [closed]

There's old houses with extensive remodels that are in need of some kind of "zoned" help in interior air quality (or "IAQ", I'm not sure how common this acronym is just yet), ...
MacGuffin's user avatar
  • 393
0 votes
0 answers
26 views

Minisplit Install With Thin-Walled Lineset

I'm currently installing a multi-zone minisplit in my home. Unfortunately, I bought the cheapest linesets I could find. The 1/4" line has thinner walls and is very difficult to flare and torque ...
scott's user avatar
  • 21
0 votes
1 answer
200 views

Can I cover part of my mini-split cooling coil to remove more moisture?

At night during the summer, we run the kids room mini split with the door closed, and I've noticed the humidity gets really high (measured at > 70%). This surprised me, as I assumed the AC would be ...
Evan's user avatar
  • 281
0 votes
3 answers
566 views

Mini split to cool one room and heat another

We live in a three story house, with our bedroom in the third story loft. On sunny days, it gets too warm up there, even with the windows open (not to mention the neighbor’s 4:00am rooster crowing). ...
Chad's user avatar
  • 1
2 votes
1 answer
290 views

Couple of questions on the outside unit of a split heat and A/C installation

I have a Viessmann heat and A/C installation where a single large common outside unit located on the roof connects to split units on three separate floors. First question: There is a pair of copper ...
Sabuncu's user avatar
  • 173
0 votes
2 answers
297 views

Possible to install a mini-split condenser inside-ish?

Trying to install a multi-zone mini-split heat pump system in a small condo that does not have any accessible outdoor space* for condenser unit, however in the region jalousie windows are common and ...
Jared Zimmerman's user avatar
1 vote
1 answer
40 views

Configuring FHW heating system as a backup to minisplit

I installed a minisplit HVAC (well, HAC) system a few years ago. Very happy with it as housewide AC, mostly happy with it as heating (more efficient than the high-efficiency gas forced-hot-water ...
keshlam's user avatar
  • 29.5k
1 vote
3 answers
1k views

Insulating outside minisplit lines

I need to insulate two outdoor minisplit lines. They are 3/8 and 1/4 inch copper lines - approximately 15 feet. Edit: They came with insulation but after several years it is damaged and needs ...
Aaron Kreider's user avatar
3 votes
2 answers
4k views

How do I wire a mini split that requires 208-230V with a 15A breaker, but came only with single pole wiring?

I am installing a Rovsun 12,000 BTU mini-split with heat pump. The voltage range is 208V-230V. The wiring for the unit consists of L1 Black hot wire, L2 White neutral wire, and the green ground wire. ...
Chris's user avatar
  • 31
1 vote
2 answers
469 views

Can I use just split units for winter heating if I have both mini splits and hydronic base board heaters?

We're trying to go all-electric/solar and reduce reliance on fossil fuels. We currently have an 11 year old propane tankless combi-boiler that supplies hot water and also circulates water through a ...
Kristoph Matthews's user avatar
1 vote
0 answers
176 views

Multi-split Daikin air-conditioner errors and temperature issues

I have two indoor Daikin Perfera FTXM-R units hooked to a 2MXM-N9 outdoor unit. What I noticed is that the indoor unit closer to the outdoor unit (A) will start to report a very low temperature if I ...
Andrei Pietrusel's user avatar
1 vote
3 answers
307 views

What data is available to support decisions about thermostat set point with mini split heat exchangers?

I have seen tons of references that say that the best way to run a mini split heat pump is to set it to target temperature and to let it maintain that temperature all day long, not differentiating ...
zelinka's user avatar
  • 232
3 votes
1 answer
1k views

Mini split beeping every 34 seconds

My Mitsubishi MSZ-FH09NA mini split head just started beeping. It beeps every 34 seconds whether on, off, or disconnected. This beep sounds slightly different than the on/off/function beep (quieter, a ...
Evan's user avatar
  • 281
1 vote
0 answers
2k views

Heating is not working on DIY Dr Cool Mini Split

I recently installed a 3rd Gen 24k BTU DIY Dr Cool Mini Split Heat Pump, but I'm not able to get the heat working. The indoor unit does cool, but it doesn't doesn't do anything when I switch to heat ...
st4rgut's user avatar
  • 211
1 vote
1 answer
130 views

Can my mini split disconnect be around corner of wall

I am looking at locations to install my mini split outdoor unit. One location would be: you are facing the outdoor unit, on the right of the unit, the wall ends about 12 inches away and turns back ...
user903805's user avatar
1 vote
1 answer
10k views

MRCool 24k BTU breaker size, wire gauge and disconnect box

I am looking to install a: MrCool E Star DIY 4th Gen 24k BTU Ductless Mini-Split Heat Pump Complete System 208-230V/60Hz I reached out to MRCool support and they confirmed what I found through google ...
user903805's user avatar
0 votes
2 answers
4k views

Wiring mini split external and internal

I am looking to install one of the MRCool DIY mini split in my garage. I currently have a 30amp 240v break and have run 10 gauge wire to a 20amp receptacle for my air compressor. Can I just use some ...
user903805's user avatar
1 vote
0 answers
224 views

How to connect the refrigerant lines of the DIY Mr Cool Mini Split in Tight Space?

I want to mount the indoor unit of the DIY Mr Cool mini split on a wall inside the house that is a few inches across from a shed. Unfortunately, the proximity of the shed prevents me from accessing ...
st4rgut's user avatar
  • 211
1 vote
1 answer
726 views

Should I cut out this repaired kink in a copper line set? (3/8")

I'm installing a mini-split, and in a moment of carelessness I slightly kinked the 3/8" copper line (the larger one). I repaired it using the 'wrench method' with some nylog to lubricate, and now ...
tom's user avatar
  • 384
3 votes
2 answers
235 views

Mini split for 14x15 room addition

We have a 14x15.5 family room addition on a slab. For summers we've used a window a/c. The room connects to the kitchen via a small 4.5 x 4.5 foyer. It has a doorway with the door removed. The rest of ...
mike_s's user avatar
  • 31
1 vote
2 answers
244 views

Understanding heatflow, minisplit vs. open stairwell

Still getting used to the minisplit heat-pump HVAC (well, HAC) system I put in a few years ago, along with improving the house's insulation. One of the differences I'm noticing from when I was heating ...
keshlam's user avatar
  • 29.5k
2 votes
2 answers
149 views

Wiring for mini split sysytem

My mini split system call for a 12/3 wire on a 30amp circuit. I thought i had to use 10/3 wire on a 30amp circuit. Is it safe to use the 12/3 wire?
Steve Maningas's user avatar
1 vote
2 answers
2k views

Can I upgrade an existing breaker to add more load to a full panel?

I want to add three mini split systems to my house (two 18k, one 9k). I have a 100 amp panel that is full. I did a load calculation and with the additional mini splits I will be at 89 amps total (I ...
Gary H's user avatar
  • 23
1 vote
1 answer
6k views

Meaning of "standby" indicator on Mitsubishi mini-split

We live in western Washington state, and have an eleven year old Mitsubishi heat pump system consisting of: PUMY-P36NHMU(R1) City Multi outdoor unit (service & technical manual) PKFY-P18NHMU-E ...
dlu's user avatar
  • 508
0 votes
1 answer
90 views

Thoroughness of residential mini-split plumbing tests

I'm installing a Bosch Climate 5000 series 3-zone mini split system in my house. This is my third mini-split installation (although I had an HVAC guy deal with the plumbing on the first one). HVAC ...
Rick's user avatar
  • 525
0 votes
2 answers
468 views

Do I need 5 separate disconnects for my 9k btu 5 zone mini split?

I’m installing a 5 zone 9k btu mini split and I’m not sure where to start with the wiring. Looked in the manual there’s a few different ways. I was hoping to use one box for my upstairs units (2) put ...
user157252's user avatar
0 votes
1 answer
58 views

Mini Split Leaking

I have 2 ductless Comfort Star mini-split units that were installed by a licensed contractor. One of them drips water from the air outflow. The contractor came out, took it apart, wet vacced out the ...
AKG's user avatar
  • 101
0 votes
2 answers
4k views

Can I put more than one single-zone ductless mini split on a single branch circuit?

I’m planning to replace my old central forced air HVAC with mini split systems, but for a number of reasons, it will be more than a single multi-zone compressor. In that regard, am I required to have ...
Rick's user avatar
  • 525
1 vote
2 answers
245 views

mini split line set run

I was looking to do a diy dual mini split unit one condenser 27k BTU 22 seer. Two heads 12 & 18k. One head will be in the garage next to the electrical panel and the run for that is less than 10ft....
Envieddesigns's user avatar
0 votes
0 answers
94 views

Are there any ductless mini split systems that can use standard HVAC control wiring cables

I have a worn out 1990's quad mini-split system that use a separate class 2 (power limited) 24v control cable 18/5 to each indoor unit. The power for the indoor and outdoor units comes from 2 separate ...
Oliver Street's user avatar
0 votes
0 answers
26 views

Watertight connector for Honeywell genesis 10753908

I have some Honeywell Genesis 10753908 cable that I need to connect to a mini split outdoor unit. The thing is outdoors, so it should be a wet and UV rated connector. Unfortunately, I have been ...
zelinka's user avatar
  • 232
0 votes
1 answer
160 views

Long refrigerator line in split AC

I'm considering a split AC/heat pump install for my house. However, one set of location (compressor on the ground, air outlet on second floor) would require running the refrigerant 15 vertical feet up,...
Jessica's user avatar
  • 281
0 votes
0 answers
2k views

Running line set for minisplit through soffit

I am installing MrCool DIY minisplits. I am wishing that I had just hired a professional, but unfortunately I'm too deep into this to change course at this point. My question is whether it is okay for ...
reynoldsnlp's user avatar