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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Mounting external component of split AC on hollow brick wall

I have a small split system (Philco Phs25ha4cpi). The external component weighs 25kg, and I have mounting brackets like these: And a wall made from bricks like these: My question is what kinds of ...
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2 votes
2 answers
101 views

Ductless mini-split AC with multiple indoor units for a home with small bedrooms?

Location: US, NYC. I want to improve the air conditioning setup for an apartment in a 2-family house. Current situation: 200 sq ft master bedroom, horrible old through-the-wall AC on a dedicated 20A ...
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6 votes
1 answer
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Can I use different wire gauges in quick disconnect and from panel?

Quick disconnect kit came pre installed with 10 gauge wire. The split AC unit calls for a 20 amp double pole (2 hots). So that sounds like 12 gauge. I realize it’s probably okay to do 10 gauge for the ...
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What does a mni split AC do for thermostat?

I have a Hessaire mini split in a garage room. It's installed in the wall and has a remote. It acts like it has thermostat control (you can set the temp), but it is all over the place temperature ...
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Installing mini split system without wall core and running line set in attic

So the mini split I purchased calls for 3.5 inch hole to be cored from the handler unit to the outdoor compressor. It’s always painful for me to see beautiful poured block walls destroyed, so my ...
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What kind of conduit do I need for my mini split AC line?

Running 240V for mini split through exterior wall in conduit from indoor unit to outdoor unit. Cable supplied by mfg is SJOW 16/4 105c 251603 3/8" O.D. Can use 3/4" non metalic flex conduit (...
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Head Scratcher: Mini Split Conduit Question [duplicate]

I'm installing a Mr Cool 24K BTU DIY mini split 240v system. It's replacing one that worked flawlessly for 2 years. The manufacturer replaced my original one because of a manufacturing defect - ...
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Convert 30 amp outdoor outlet to 30 amp ac disconnect

I'm planning on connecting a mini-split condenser to an unused 30 amp outlet I have outdoors. My plan was to add a 30 amp fused disconnect. How do I go about handling the outdoor gang box? Would I ...
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2 votes
5 answers
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110v vs 220v Mini Split Efficiency

I am under the impression that, as a general rule, 110v heating and cooling options are inherently not very efficient. So I was surprised to find a 110v mini split shopping around with a fairly decent ...
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mini-split drain and insulation question

I have a mini-split cassette (ceiling install) in my garage. Two questions for you guys and gals. Do I need to pour bleach down the drain line for a mini-split? I do this for my HVAC system. There is ...
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Is it ok that I ran 12-3 cable for shed mini split from shed sub panel to AC disconnect instead of 12-2? [duplicate]

I have a 240v LG mini split that uses 15 amp breaker. It only needs two lines and a ground. I mistakenly ran 12-3 when I should have run 12-2. Is it okay to leave the wire In place and just not ...
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2 answers
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Mitsubishi mini-split not cooling very well

We have a 12,000 BTU Mitsubishi mini-split cassette in a two-car garage in Houston. The garage is insulated on two sides and not insulated on the wall that faces the sun. The door is insulated. The ...
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Recommended sleeve size for mini split line set

Before I grout my CMU walls, I want to sleeve them for a mini split line set. I’m not sure what unit I’m going to buy yet. Is 2 and a half inch enough (or considered standard) ... or should I sleeve ...
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How to shorten this pipe from AC condensation pump?

I have a mini-split AC unit with a built-in condensation pump. This pipe is connected, but it goes down and up like a U. The manual says it must go upwards to prevent water from pooling in the pipe. ...
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Split multi-zone air conditioner (not a heat pump)

I'm considering adding air conditioning to my home in Seattle. I have a modern, high efficiency gas furnace for heat. It would be easiest for me to add air conditioning using mini split technology. I ...
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2 answers
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Two floor home cooling with one ductless heat pump split mini mounted on second floor

I live in Seattle where we have a relatively small number of days where it gets hot enough to need AC. I live in a two story house where the two floors, each being 1200 sq ft in area, are connected by ...
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Can I use a liquid line with a slight dent?

Installing a mini-split in the US. On the indoor units, the liquid line coming from the unit is 8mm, not 1/4, though it has 1/4 flare fitting. Trying to bend the line into position, I've indented the ...
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Placement of indoor minisplit unit

I am about to have a Mitsubishi minisplit installed. In case it matters, the installation will be on an interior wall; on the other side of that wall is a closet with a sump pump which we will use ...
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Best route to get power to mini split

I'm installing a small minisplit for my garage. The garage is part of the house (front right corner of the house) and I have to put the minisplit condenser in the back of the house. My breaker panel ...
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Daisy Chain 120V Disconnect Box from existing 240V box

I have an existing AC unit that hooks up to a 3 wire 240V 30amp disconnect box serviced by a 30 amp two pole breaker. I am adding a small 120V two wire mini split AC right next to it and I would like ...
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Mr Cool Ductless Mini Split 9k BTU

I am trying to figure out the wiring for this model I am installing. The minimum circuit and max fuse is 15 amps. What size wire and breaker do I need? Also do I need a disconnect for this mini split?
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Lineset sizing for multi-zone mini-split

I'm installing a 48k multi-zone mini-split in the garage. The zones are 18k, 18k and 12k. All of the indoor units say they require 1/4" x 1/2" linesets in the install manuals. The ...
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10 gauge whip off disconnect box fed from 12/3 on 15 amp breaker for Mini Split?

I'm wanting to make sure my shopping list is correct for my mini split install. The mini split, Senville SENA-09HF, uses a 12/3 wire and requires a 15 amp breaker. I'm planning to buy a non-fused ...
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Can't find SEER rating for Bryant Split AC system

I own an older house with a hot water heat system and I am want to get a Split AC system installed. The setup involves 2 9,000 BTU units, one in each 2nd floor bedroom and a 12,000 BTU unit on the ...
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1 vote
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Brand new Fujitsu Halcyon split system unable to keep temperature

We had a Fujitsu split system installed, with 4 indoor units. The issue I'm seeing is that the system is behaving in a way that I can only describe as "erratic". We're observing a couple of ...
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Diagnosing CH 05 (communications failure) in LG mini-split system?

I installed a mini-split system in my shop (it's the second mini-split I've put in; the first went great). Everything appears fine, except that after a few minutes, the system shuts down and the ...
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Mini split whirring sound

I recently had a new cooling only 12K inverter mini split installed in my bedroom which I run 24/7 on low fan speed. The unit is very quiet and I am generally pleased with it. However I have noticed ...
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1 vote
2 answers
1k views

How bad is it to have low spots in a mini-split line set?

I'm about to install a mini-split system in my shop, and several online sources have recommended strongly against coiling extra line set length, because it creates a low spot that traps condensed ...
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Mini-spit AC unit consuming electric power when off

I have discovered that my recently installed mini-split is still consuming electric power when it is turned off. This is a 12k btu cooling only TGM mini-split inverter. I noticed that it seemed to ...
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2 votes
3 answers
1k views

Can I use exposed UF instead of THHN in conduit to outdoor AC disconnect?

I'm installing a mini-split and need to run power outside to the disconnect box, then an additional line from the disconnect to the compressor unit. In most installs I've seen, power to the the ...
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1 vote
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Extra valves on AC lineset?

I'm installing a mini-split system in my shop, but realize I’ll probably need to move the outdoor unit in 6-12 months. Does it make sense to try to add a pair of valves to each line to allow them to ...
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Run mini-split heat pump heads at different temperatures

I vaguely remember the contractor who did maintenance on our ductless heat pumps two summers ago telling us not to set the thermostats of the two small heads that share an outdoor unit to different ...
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0 votes
1 answer
187 views

Reusing old service wires from electric furnace to mini-split

EDIT to answer replies: @3phaseeel 30-amp wires are 6 AWG aluminum, 50-amp wires are 4 AWG aluminum. The sheathed wires run along the garage roof truss overhead (see picture), exposed for about 28 ...
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Installing ductless units in my apartment. What am I supposed to do with all these coolant and drain lines?

I'm installing 3 ductless AC units in my apartment. I know the lines are supposed to go outside and connect to the condenser but there are three coolant lines wrapped in insulation and three drain ...
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2 votes
1 answer
584 views

Are the indoor unit's fan suppose to stop when set temperature is reach for Dakin mini splits?

I have a Daikin ductless heat pump with 3 heads. When the set temperature is reached, no heat comes out and the fan stops? Is the indoor fan supposed to stop after reaching the set temperature? I don'...
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12/3 to disconnect box for mini split install?

I have an issue with installing a disconnect box for my 24k LG mini split condenser unit. 12/3 is coming from 20 amp double pole breaker to disconnect box with surge protection box(ICM517). I ...
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1 answer
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Leak check mini split AC

I am finishing up a 6 zone mini split DIY installation and before closing up some of the walls I would like to do some leak checks. My set up is that from the condenser it splits into 2 branch boxes ...
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2 votes
1 answer
154 views

Mini split minimal pipe length

Quick question - my LG mini split manual says that I need a minimal of 10’ from the indoor unit to the branch box. My question is do I include the 1-1.5’ piping that comes with the indoor evaporator? ...
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2 votes
1 answer
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Piping gravity fed condensate line down interior wall into crawlspace then through rim joist to outside

Mini split piping and control lines will run up the outside of the house into attic, then to interior Wall units. I can’t run the condensate drain lines on this path without pumps. The idea is to run ...
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0 votes
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Replacing Central air with a Split system

I'm trying to replace two central Air conditioners (one per each floor. 2-3 ton each) in my home and I'm not sure if I should go with Ductless (because of a much lower cost) or pay higher and replace ...
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1 vote
1 answer
304 views

ON Electrical Code: 240V line from panel to exterior (fused / nonfused subpanel) for AC

I'm a complete newbie to this so I have a few questions... 1) Gauge of wire from panel to exterior subpanel? I know it's two live from a 220V breaker and neutral, also do I need GFCI, or a standard ...
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1 vote
1 answer
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Best tool for cutting a 2" horizonal sloped canal cut through a 11' plaster/lath internal wall

In one room I need to cut groove into a wall to accommodate a condensate drain from a minisplit air handler/evaporator in an adjacent room. I know I could use a pump but I rather rely on old fashion ...
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2k views

Minisplit ductless communication wire question

Simple question and I am obviously missing something, but the manual calls for 14/4 to be used as the communication/power cable. That is 1 wire for communication, 2 hot wires and lastly one for ...
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ductless air handler install

So I am about to embark on an install of a 6 zone ductless system and I have 2 questions around installing the air handlers in each bedroom. I am using a branch distribution box which needs to be ...
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1 vote
2 answers
657 views

110v outlet convert to disconnect?

I have a 110v outlet with a dedicated 20 amp breaker. My question is can I remove outlet and run the same 12/2 wire to the outside wall about 4 feet away from outlet and turn it into a disconnect box ...
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0 votes
3 answers
5k views

My Acacia dining table starting to show some huge splits or cracks

We got this Acacia dining table from costco and noticed after a year or so it started to crack on one end. Initially the crack was pretty tiny and now it's very noticable.I was wondering what are the ...
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2 answers
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Mini Split Condenser wall mount on wood exterior wall

We have a wood-frame house with 2x4 studs and half-inch plywood exterior walls. What is the generally accepted best practices for mounting a 80lb mini split condenser on a wall bracket to this type of ...
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0 votes
1 answer
480 views

Mini Split liquid line shaking

I just installed a new Mr. Cool system a few weeks ago. Works great, its quiet and works as expected. I haven't finished the lineset covers since the routing is a bit wonky so I was able to see the ...
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0 votes
2 answers
2k views

New mini split ac on existing Spa disconnect

I'm installing the mini split and wiring it to the disconnect they had for a spa which is now long gone. They wired a 110 gfci off the disconnect which I'm not touching. Coming in from the main ...
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1 vote
0 answers
1k views

Does cabling between a mini-split indoor and outdoor unit need conduit?

I am installing a mini-split AC system where there are multiple indoor units connected to a single outdoor unit. For each indoor unit, there is a separate 4-conductor cable that connects to the ...
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