DIY install of non-Mrcool units

[JackOfDiamonds]

Is it feasible to buy the tools, gauges, etc needed to install a mini split unit myself? Or does it require licenses?

I already have things for soldering and brazing

 

[American Locomotive]

It's totally feasible. You need 4 tools to do the job properly: Manifold gauge set, vacuum pump, core removal tool, micron gauge. You can pick all of that up for about $250 or so.

Licensing is another story, and varies by state and county.

No soldering or brazing necessary with most minisplits.

 

[MattGarage]

I've done some DIY AC and the various split units make it easy. Follow instructions and don't lose vac or coolant is the name of the game. A proper R410a gauge (the retail ones are often R134a/not high enough range), tools patience and checking, rechecking is the game. Even if worst case scenario happens and vac is lost or coolant lost - there are ways to resolve that with creative use of ebay and a vacuum pump.

In my view the hardest part would be running the coolant lines. The rest is triple checking work and then letting it rip!

Since I'm in California this is all hypothetical. Maybe where you are isn't as much a nanny state.

It's awesome that there are lot of videos on yt about end to end installs on the splits.

 

[juddspaintballs]

Totally feasible and not that difficult. Where I live, I can build a house start to finish and do every lick of the work myself without any special licenses. Where you live may or may not have rules about what you can and cannot install yourself.

 

[pcmeiners]

You would also need a high pressure nitrogen regulator , tank, and a torque wrench, all adds up.

Depends how the warranty is written, many manufacturers have lawyer go over the warranty, making sure DIY is not an option, at least that is what they want you to believe; check out Mitsubishi's warranty, they covered all bases against DIY. Warranties are rigged so dealers and major purchasers have the advantage. I am sure not all stipulations will hold up to states attorney generals or consumer protection laws. Also, your supposed to be 608 certified to play with minisplits, by Federal law, and most manufacturers require licensing by state (if required).
As noted brazing is not required, one piece copper lines are used. If you plan on doing it yourself, you better be able to do a clean, moisture free and leak free install or you will end up paying a lot more than you count on.

 

[danski0224]

Is it feasible to buy the tools, gauges, etc needed to install a mini split unit myself? Or does it require licenses?

I already have things for soldering and brazing

Download the installation manual, read it, decide for yourself.

 

[arrowhead]

Easiest install ever. No wonder all the HVAC companies push these so hard, a monkey could install them. No special tools, no gauges, no vaccuum pumps needed. Units come precharged, all connections are sealed with valves so no risk of refrig loss or contamination of the lines. Connect the lines, open the valves and sit back in the cool breeze from your new A/C

 

[kaymccampbell]

Easiest install ever. No wonder all the HVAC companies push these so hard, a monkey could install them. No special tools, no gauges, no vaccuum pumps needed. Units come precharged, all connections are sealed with valves so no risk of refrig loss or contamination of the lines. Connect the lines, open the valves and sit back in the cool breeze from your new A/C

Not all are so easy. Most require a vacuum pump and a gauge set.

 

[purplezr2]

Easiest install ever. No wonder all the HVAC companies push these so hard, a monkey could install them. No special tools, no gauges, no vaccuum pumps needed. Units come precharged, all connections are sealed with valves so no risk of refrig loss or contamination of the lines. Connect the lines, open the valves and sit back in the cool breeze from your new A/C

That is for units that have lines designed for DIY.

The non-DIY units are still precharged in most cases, but you still need draw a vacuum on the systems and utilize a micron gauge to measure said vacuum.

Biggest thing I noticed is the if you go DIY you have to use the line set length given with no matter what as you can't cut the line set.

If you go Non-DIY you can cut the line set down(read the instructions there is a minimum based on charge level) to a desired length to fit your need.

I did my own Pioneer install that had a precharged outside unit and cut my line set down to the length I needed.

Only tools I needed to purchase was the Micron gauge. Had a pump and manifold set, along with flaring tools.

 

[PoorUB]

Easiest install ever. No wonder all the HVAC companies push these so hard, a monkey could install them. No special tools, no gauges, no vaccuum pumps needed. Units come precharged, all connections are sealed with valves so no risk of refrig loss or contamination of the lines. Connect the lines, open the valves and sit back in the cool breeze from your new A/C

The majority of HVAC shops do not use precharged line sets.

 

[arrowhead]

Don't get me wrong, I hate the things but they do have thier place. And of course, they are not all DIY but if you're handy but don't have the tools it can still be done.

 

[justinjoyal]

Don't get me wrong, I hate the things but they do have thier place. And of course, they are not all DIY but if you're handy but don't have the tools it can still be done.

Easiest install ever. No wonder all the HVAC companies push these so hard, a monkey could install them. No special tools, no gauges, no vaccuum pumps needed. Units come precharged, all connections are sealed with valves so no risk of refrig loss or contamination of the lines. Connect the lines, open the valves and sit back in the cool breeze from your new A/C

Most DIY jobs I come across are ****. I guess not all monkeys are the same...

 

[PoorUB]

Most DIY jobs I come across are ****. I guess not all monkeys are the same...

For what it is worth, many HVAC guys can't do a decent install either!

 

[honcho]

You would also need a high pressure nitrogen regulator , tank, and a torque wrench, all adds up.

Depends how the warranty is written, many manufacturers have lawyer go over the warranty, making sure DIY is not an option, at least that is what they want you to believe; check out Mitsubishi's warranty, they covered all bases against DIY. Warranties are rigged so dealers and major purchasers have the advantage. I am sure not all stipulations will hold up to states attorney generals or consumer protection laws. Also, your supposed to be 608 certified to play with minisplits, by Federal law, and most manufacturers require licensing by state (if required).
As noted brazing is not required, one piece copper lines are used. If you plan on doing it yourself, you better be able to do a clean, moisture free and leak free install or you will end up paying a lot more than you count on.

Not always, but often, the monetary savings of DIY is well worth the potential cost of not having a warranty.

 

[arrowhead]

Most DIY jobs I come across are ****. I guess not all monkeys are the same...

No offense to the HVAC installers out there. But in my opinion mini splits are just through wall units that got split in two and are no sustitute for a central system with proper distribution, filtration and humidity contol. Yet they get pushed hard by HVAC companies because the profit margin, ease of install and low risk of call backs. Not that its the best solution for the customer.

 

[justinjoyal]

No offense to the HVAC installers out there. But in my opinion mini splits are just through wall units that got split in two and are no sustitute for a central system with proper distribution, filtration and humidity contol. Yet they get pushed hard by HVAC companies because the profit margin, ease of install and low risk of call backs. Not that its the best solution for the customer.

You obviously can't compare a 3k mini-split to a 20k central system...

Most homes don't have ducts around here. Mini-splits are great for most people.

 

[jjrbus]

License? Don't know, mini works fine without it. I DIY installed 3 Daikin. I am retired and have the luxury of time and spent at least 100 hours researching. 4 years ago 2/3 of the mini install info available was garbage! There are some great videos available today, but most are still bad. If you see someone using a non torque wrench doing an install they are not doing it right! Unlike old refrigerants the minis run up to 600 psi, not gud enough, duct tape, bailing wire territory.

I bought a Daikin mini install kit, which includes a flair gauge, can't imagine doing flairs without one. Now after the install trying to find someone to service a problem is, well here in SW FL I have not found a tech to work on mine. Have had 2 here, one was incompetant and the other was a crook. Did not want to look for a leak, just gas and go $400. Turned out to be leaking evaporator coil, which I found with my brand new hyper-sonic leak detector.

It is not rocket science to install a mini but does need to be right, which requires the right tools and procedures.

 

[Jackfre]

Arrowhead, I think you overlook the type of construction most people have in your area. The older housing stock is overwhelmingly hydronic oil or gas fired as it is across the NE. Yes, central ducted system have grown over the past 30 yrs but for most homes it is impractical to add ductwork to an existing home, especially the two story models. also, the central systems don’t touch the efficiency of ductless. Adding ductless to an existing home is in many cases the best way to get cooling and dehumidification. Throw in the efficient heat delivered and it becomes a pretty compelling install and the numbers sold support that. The vast majority of central boilers and furnaces are single stage and massively oversized. Running a mini-split in the shoulder seasons and not firing up the central system until there is an actual load against it that approaches its capacity also offers comfort and efficiency. The pitch I always used to customers is “don’t change your system, Add to it” with the mini-split. Are minisplits perfect? Certainly not, but I don’t see that as the equipments problem. The problem is that there are not enough Justin’s running around able to do proper, cost effective installs and be able to maintain them. Sales have outstripped the maintenance ability of the trade. In my last home my mini-splits were 12 and 8 yrs old when we sold the place last month. Perfectly reliable, a pain in the *** to clean the evaps but with the solar system the place heated and cooled for zero dollars after a 5 yrs amortization of the solar system. I could not do that with the central system which I tore out in favor of the mini-splits. Also, most central duct system just **** and blow in the worst ways. in our new place I am analyzing the duct work to see if I can run a 36k Fujitsu minisplit condensing unit to one of their new multi-position air handlers. If I can make the ductwork tight enough I’ll have a modulating condensing unit and air handler and the gas furnace will be out of there in a heartbeat. I’ll add solar and do what I did on the last place. another reason to go to the mini is that I can get rid of the 3 ton Lennox condensing unit. It is much noisier than the Fujitsu. Also the Fujitsu is much smaller. the Lennox looks like the *** end of a 54 Packard and is about as large. this has been fun

 

[danski0224]

Also, most central duct system just **** and blow in the worst ways.

I just looked at a system with a 5 ton AC unit.

There are a total of (5) returns visible that are connected to the ductwork. All of these use the building cavity at some point, built before enforcement (or existence) of 2012 energy code.

The top of the ductwork was looked at, to see if there were any "extra" holes cut into it (a common technique for shoddy residential systems short on ducted return).

The airflow was measured at each return grille, one of these is a "high/low", so 6 wall openings.

A "5 ton" system needs to move ~2,000 CFM of air.

A grand total of 870 CFM was measured at the return grilles.

There was 1780 CFM measured in the return drop.

The ductwork in place, by design, falls short of being able to carry 2,000 CFM (1,860 CFM capacity based upon duct size).

It has been proven by NCI that the average, unsealed metal duct system will have a minimum leakage rate of 20% and 30% is not uncommon.

There is a 220 CFM shortfall right off the bat (2,000 - 1780).

Then there is 910 CFM of air coming from somewhere between the return grilles and the measurement point in the return drop (1,780 - 870).

And the installed equipment is about 1.3x as big as it needs to be.

Yup, anyone can do this stuff.

And yes, shoddy ductwork kills the system performance.

 

[pcmeiners]

"Not always, but often, the monetary savings of DIY is well worth the potential cost of not having a warranty"

Most of the time the warranty on minisplits are worth ****, your lucky if you get a piece of hardware replaced, your not getting the diagnosis cost or labor reimbursed... most warranties are a scam, by the time the labor and diag costs are met, for a bit more you you can get a new system.

"No offense to the HVAC installers out there. But in my opinion mini splits are just through wall units that got split in two and are no substitute for a central system with proper distribution, filtration and humidity control. "

Duct distribution of heat and cooling is the most inefficient form of transferring heat. To each his own, if you like high energy costs use ducts.

 

[danski0224]

Most of the time the warranty on minisplits are worth ****, your lucky if you get a piece of hardware replaced, your not getting the diagnosis cost or labor reimbursed... most warranties are a scam, by the time the labor and diag costs are met, for a bit more you you can get a new system.


Duct distribution of heat and cooling is the most inefficient form of transferring heat. To each his own, if you like high energy costs use ducts.

Goodman was the only manufacturer that I heard of that would pay labor and diagnostic costs, albeit at their rate, for residential equipment. Not sure if this is CURRENT practice.

I have never received anything but a part from other manufacturers/suppliers. This does not include refrigerant or other "parts" needed to make a warranty repair, much less labor or diagnostic time.

The warranty language is good for the consumer, ****** for the contractor.

Yes, poorly installed ductwork is bad.

People can get fussy about register placement, much less something sticking out of the wall, that they will maintain.

 

[MattGarage]

To each his own, if you like high energy costs use ducts.

Is there an alternative to ducts? My house has a labyrinth of ducts and two central AC/heaters (attic/two story). It's fine but I can see the limitations of ducts but are we doing something wrong?

 

[housewolf]

Is it feasible to buy the tools, gauges, etc needed to install a mini split unit myself? Or does it require licenses?

I already have things for soldering and brazing

I’m about to find out. I worked in this “business” for 40+ years but much more on the piping side of HVAC. Some refrigerant but mostly commercial heating & chilled water. I helped my partner install a Mits two zone in my garage/upstairs loft last year. I just ordered a single zone Daiken for my shop last week. I can use his equipment but I’m on my own for the install.

 

[American Locomotive]

No offense to the HVAC installers out there. But in my opinion mini splits are just through wall units that got split in two and are no sustitute for a central system with proper distribution, filtration and humidity contol. Yet they get pushed hard by HVAC companies because the profit margin, ease of install and low risk of call backs. Not that its the best solution for the customer.

The thing is, most central systems do not have proper distribution, filtration or humidity control. The reality is that in many cases now, they are not the best solution for the customer.

• Getting air distribution correct with a central ducted system is very difficult in a residential setting. You can get it very close for a specific time of year/condition. However outside of that range, you will almost always end up rooms that are little too hot or a little too cold (unless you leave the door to every room open all the time).
• Individual temperature control/Zoning is very expensive, fiddly, and typically unreliable with residential ducted systems. Residential damper actuators are terrible, and the companies that make these systems typically won't support you (or just don't exist anymore) 10 years down the line when it starts going wrong.
• Most new construction homes in this area resort to installing two separate systems if its a multi-story home in lieu of a zoned system. That's two furnaces, two condensing units, two sets of duct work, twice the labor, and twice the cost.
• Humidity control is a big problem with ducted systems, as most of them are fixed capacity, or maybe two stage. So mild, but humid days, your house will feel like a swamp because the system will bring the temperature down fast without actually running long enough to remove any humidity from the air. There are true variable capacity central systems now, but they are huge money
• Speaking of cost: The cost for central systems has absolutely skyrocketed. The equipment costs an astronomical amount of money, and it seems like installers are now just going to keep increasing their labor rate 20% each year until the customers just stop calling.

Mini splits on the other hand offer:

• Affordable: Even premium brands like Fujitsu or Mitsubishi are downright affordable compared to all-in costs for many central systems.
• Easy zoning/individual temperature control with multi-head units or even just installing multiple single head.
• They're all variable capacity, so they offer excellent humidity and temperature control year round.
• Very fast install and replacement, and minimal space taken up inside the home for equipment. Can't say that about ducted systems.

I will give you that a central system CAN provide better air filtration, but that is not always a given. Plenty of equipment still uses very basic mesh filters.

 

[N_Jay]

Great discussion.

I swill be doing one or two minisplits in my shop this summer.

DIY kits seem needlessly expensive, and maybe not the best quality.
I don't mind using precut lines and coiling the extra if it saves me the possibility of a bad flare.

Anyone in the Charlotte NC and like to work for beer and pizza?

 

[danski0224]

Anyone in the Charlotte NC and like to work for beer and pizza?

Do you work for beer and pizza ?

 

[danski0224]

Is there an alternative to ducts? My house has a labyrinth of ducts and two central AC/heaters (attic/two story). It's fine but I can see the limitations of ducts but are we doing something wrong?

The mini split heads all need refrigerant piping, power from the outside unit, and a condensate drain.

The multi head units also need to be piped correctly.

One can easily trade poorly installed ductwork for poorly installed refrigerant piping.

 

[jjrbus]

2 companys are making minis with easy to remove blower wheels for cleaning. I do not remember both.

 

[housewolf]

Great discussion.

I swill be doing one or two minisplits in my shop this summer.

DIY kits seem needlessly expensive, and maybe not the best quality.
I don't mind using precut lines and coiling the extra if it saves me the possibility of a bad flare.

Anyone in the Charlotte NC and like to work for beer and pizza?

This is what I found. Originally, I was going to get a Mr Cool DIY @ full retail. I had a Daiken unit priced through the company I work with and it’s significantly less. For the inconvenience of making a couple of flares (I’m a retired plumber) & pulling a vacuum I can have a better unit with repair parts available and save a few bucks too.

 

[pcmeiners]

Goodman was the only manufacturer that I heard of that would pay labor and diagnostic costs,"One can easily trade poorly installed duct work for poorly installed refrigerant piping."

My comment about duct work was referring more to the hardware.... an abundance of surfaces which produce turbulence ( friction losses off the charts), squared off 90° bends, leaks, poor insulation, improper design, trapped dust, and the new consideration, very high installation cost. None of which can be corrected without extreme expense.

"Goodman was the only manufacturer that I heard of that would pay labor and diagnostic costs,"

Sounded interesting so I checked out the Goodman warranty. Maybe years ago they had a good warranty but now it is on pare with >95% of the useless warranties by mini split manufacturers.

https://hvacdirect.com/media/hvac/pdf/GSZ14-Warranty.pdf

 

[danski0224]

My comment about duct work was referring more to the hardware.... an abundance of surfaces which produce turbulence ( friction losses off the charts), squared off 90° bends, leaks, poor insulation, improper design, trapped dust, and the new consideration, very high installation cost. None of which can be corrected without extreme expense.

Yes, ****** ductwork design.

It's all in Manual D.

Unfortunately, at least in my area, residential HVAC shops either lack the ability to actually make ductwork, or in the case of (mostly) non-union shops, someone that can make it in the shop (equipment to do so notwithstanding).

The choices are limited to what the supply house has in stock.

Then, is there someone that can measure beforehand to fabricate later?

The slam it in business model really only allows for a van or box truck with flat metal inside, that's cut up and held together with cleat and screws.

A step up would be a 3 foot box brake and a Morlin portable Pittsburgh machine.

Sometimes, changes can be made to the existing installation, enough to make a difference.

 

[JackOfDiamonds]

Some users said you need N2 tank and regulator. What's that for?

I heard that you could cut down lines without having to re-flare them, if you cut down the middle and use a copper coupling and solder back together. Makes sense to me. Valid?

Third, what is the actual procedure....I understand the outside unit is charged with pressurized refrigerant and there is a valve to release it when ready. So you install the line, hook up your vacuum pump to a service port, pump down the line and verify that it's holding vacuum (how long do you wait?), then you close the service port valve, remove your vacuum pump, then open valves on the inside unit and outside unit? Or are you pumping down both the inside unit AND the lines when you have the vacuum pump hooked up?

Fourth, I have heard people who actually don't pull a vacuum on the lines at all...just hook them up, release the refrigerant, and and it works. It means there will be air and some moisture mixed into the system, and overall pressure will be a tick higher...but fundamentally I can see that working. I wouldn't plan to do this but can it actually work?

 

[American Locomotive]

Some users said you need N2 tank and regulator. What's that for?

I heard that you could cut down lines without having to re-flare them, if you cut down the middle and use a copper coupling and solder back together. Makes sense to me. Valid?

Third, what is the actual procedure....I understand the outside unit is charged with pressurized refrigerant and there is a valve to release it when ready. So you install the line, hook up your vacuum pump to a service port, pump down the line and verify that it's holding vacuum (how long do you wait?), then you close the service port valve, remove your vacuum pump, then open valves on the inside unit and outside unit? Or are you pumping down both the inside unit AND the lines when you have the vacuum pump hooked up?

Fourth, I have heard people who actually don't pull a vacuum on the lines at all...just hook them up, release the refrigerant, and and it works. It means there will be air and some moisture mixed into the system, and overall pressure will be a tick higher...but fundamentally I can see that working. I wouldn't plan to do this but can it actually work?

The nitrogen is to pressure test and check for leaks. Typically most mini-splits pressure test at 400-500 PSI. You *COULD* do it with compressed air, but most people don't have a 400 PSI compressed air source, and it will introduce some moisture into the system that will require extended vacuuming to remove.

1) Connect lines
2) Evac system to mid-range vacuum amount
3) Charge with nitrogen to 400-500 PSI. Minimum 1hr, but letting it sit over night is better. Shouldn't loose any pressure.
4) Vent nitrogen charge
5) Pull down to final vacuum (Must hold 500 microns of vacuum or less)
6) Close vacuum pump valve, release some refrigerant charge into system to break vacuum
7) Fully remove vacuum pump, release rest of charge into system.

Some Mr. Cool systems come with special pre-charged lines and special valves in the line. You do not need to pull a vacuum with these systems.

Hooking up the lines and releasing the charge on a traditional 'manual' install system will result in a poorly functioning unit that will die an early death.

 

[danski0224]

Some users said you need N2 tank and regulator. What's that for?

I heard that you could cut down lines without having to re-flare them, if you cut down the middle and use a copper coupling and solder back together. Makes sense to me. Valid?

Third, what is the actual procedure....I understand the outside unit is charged with pressurized refrigerant and there is a valve to release it when ready. So you install the line, hook up your vacuum pump to a service port, pump down the line and verify that it's holding vacuum (how long do you wait?), then you close the service port valve, remove your vacuum pump, then open valves on the inside unit and outside unit? Or are you pumping down both the inside unit AND the lines when you have the vacuum pump hooked up?

Fourth, I have heard people who actually don't pull a vacuum on the lines at all...just hook them up, release the refrigerant, and and it works. It means there will be air and some moisture mixed into the system, and overall pressure will be a tick higher...but fundamentally I can see that working. I wouldn't plan to do this but can it actually work?

Download the installation instructions and read them.

Some manufacturers have made "easy" instructions in the basic install manual, but there is more detail in the service manual.

 

[PoorUB]

Fourth, I have heard people who actually don't pull a vacuum on the lines at all...just hook them up, release the refrigerant, and and it works. It means there will be air and some moisture mixed into the system, and overall pressure will be a tick higher...but fundamentally I can see that working. I wouldn't plan to do this but can it actually work?

Installers got by with that years ago with R22 and mineral oil. Plus the systems were simpler, not as much valves and other mechanisms in the mix.

With R410 and POE oil it is a bad deal to do it that way.. POPE oil absorbs moisture and turns acidic. That will do some serious stuff to compressors and tiny electronic valves in the system.

 

[My Old Tools]

The MrCool units work great and aren't that much more than the non-DIY. I have gauges and a pump and I went with MrCool. Ingrams seems to support them pretty well.

 

[N_Jay]

Any one use Pioneer?

 

[bluedog225]

Great discussion.

I’ve heard several places that getting a flaring tool and leaning to use it property is a great idea.

The concern is that the factory flares are not uniform or good quality.

On the not pre charged units, the advice was to properly re-make all flare joints to ensure quality. And use torque tool.

I’m still on the fence. The nitrogen purge seems necessary and that whole deal adds expense.

 

[JackOfDiamonds]

I agree the nitrogen is a bummer, plus from what I'm reading you should have an eccentric flare tool which are much more expensive than the normal kind. So I'm calculating more like $500+ in tools...

I live in a desert where the air is super dry. I wonder if I could use compressed air at 120PSI, then use my 300PSI shock pump to pump it up higher. I assume the universe would end before I could pump up that much volume by hand.

I still have paintball equipment and beer brewing equipment...I could use co2 and vacuum it all back out...

 

[pcmeiners]

Roughly you need this , but sky is the limit.....

Nitrogen tank >$100..I paid over $250 for a larger tank
Nitrogen regulator, high pressure >$50...Purchase one on Ebay, after damaging a welding reg
Flaring tool $30-40... paid $40 for a unit, spent an hour sanding/polishing milling faults
Torque wrench >$100... purchase a Yellow jacket unit for $160
Gauges/hoses $>100...purchase a 4 port yellow jacket off Ebay
Micron gauge >$80.... purchased Yellow Jacket gauge $140, returned 2 other brand gauges
Valve core remover/installer $>80
Bubble test $.05 for dish detergent
optional...
608 certification, $150
leak tester >$100...purchase a Inficon D tek select $170 including new battery
if you have multiple splits....
refrigerant recovery machine used >$400, purchased gently used Appion G5 recovery unit
recovery tank >$80
weight scale used Ebay $30

Spend all this or save more than this on your first install or possibly your first service call.