Ductless minisplit brands, options, info

ChrisJ

Hi all,

I've kind of run out of things to do on the steam system and I get bored easily so now I think it's time to fix my A-C situation. For those that don't know me, I'm not a contractor, but have most of the tools needed to do this work as I repair / restore antique refrigerators as a hobby. I'll need to get a flaring tool and probably a good set of R410 gauges but aside from that I'm set. I have a pretty good understanding of refrigeration but am by no means an expert.

I'm having a hard time finding information on these systems but so far my understanding is the brands I want to look at are Daikin, Mitsubishi, Fujitsu.

Reliability is probably my biggest concern, if I'm going to throw some money at this and a ton of my time I'd rather not have to touch it for a long long time. LG seems like it would be easiest for me as a DIYer to buy, however I have big concerns about longevity.

My numbers came from just overall observations of how our current window units perform.


My questions are,

Is there any good reading material out there for installation, repair, troubleshooting of ductless systems?


What brands are recommended for someone that wants a quality system?

Does anyone have the expansion device in the head rather than the condensing unit?

Line set length, if a manufacturer states 80' max to a head, is that the entire loop (liquid and suction), or one direction? What happens if you approach this number? Is it greatly preferable to keep linesets short and sweet, or is it ok to run a super long one to hide it?

Do pros make their own linesets, or use premade stuff? I'm asking this because it seems like running through my basement, over foundation walls, and inside interior walls may be easier to make my own rather than try to snake flared ends and crap everywhere.

Mixing head sizes? On multi-headed units, is it acceptable for all brands to mix head sizes? For example, a 9K and a 7K on an 18K condensing unit. I'm assuming yes as they seem to generally give you a range of load sizes you can connect, for example 18,000-21,000.

Do all linesets on multiheaded units have to go back to the condensing unit? Are there other options such as some kind of interfacing device? This only comes to mind because I'm assuming these get used in office buildings and it would seem easier to run a single huge liquid line and suction line to some sort of device and then branch off of that to a bunch of smaller ones. Perhaps a dumb idea, but I figure it can't hurt to ask. Stranger things exist.



Here's two plans I came up with, so far. The first one uses two separate units on the first floor and one multi-headed unit on second. The second one, uses one for first, and one for second but has the really long lineset to one head that I'm concerned about.









Before it gets said, this will not be used for heating my house except perhaps, in the fall and spring and in emergencies. The primary job of this system is cooling.


Thank you for your time, I really appreciate it.

Bob Bona_4

Hi Chris, I've got factory training and job experience. I'd peruse mfr resource libraries?

I've used Mitsubishi and Fujitsu. Had 2 issues with Fujitsu in 11 yrs. Still my main brand. Daiken haven't used bc of local availability.

80 foot is one way. I'm really liking the white coated insulated lines. About time; easy pull, no rips.

Fujitsu at least, wants a minimum of 10' line set if memory serves.

Mfrs have charts of approved multi head combos.

As far as I know all heads interface with their particular heat pump.

ChrisJ

Bob Bona said:

Hi Chris, I've got factory training and job experience. I'd peruse mfr resource libraries?



I've used Mitsubishi and Fujitsu. Had 2 issues with Fujitsu in 11 yrs. Still my main brand. Daiken haven't used bc of local availability.



80 foot is one way. I'm really liking the white coated insulated lines. About time; easy pull, no rips.



Fujitsu at least, wants a minimum of 10' line set if memory serves.



Mfrs have charts of approved multi head combos.



As far as I know all heads interface with their particular heat pump.

Hi Bob,
Thanks for commenting.

I'm probably just doing it wrong, but I've had a hard time finding anything on the manufacturer's websites. Seems like they're aimed mainly at the public so I have easy access to owners manuals (useless) and catalogs. But actual installation stuff is difficult.

I just found out about Fujitsu's branch boxes and it's really got me interested. Seems like I could do the entire house, both floors with one outdoor unit and 2 branch boxes.

Oh, the cool stuff I could build until my wife shoots down the entire thing..........

http://www.fujitsuklime.com/wf-doc/utp-py03a-branch-box-freonska-ispostava-za-do-3-unutrasnje-installation-manual.pdf

Bob Bona_4

Do you need that extra complexity? Looking at more than 80' line to a head?

ChrisJ

Bob Bona said:

Do you need that extra complexity? Looking at more than 80' line to a head?

Not so sure, it seemed like a good idea to use one unit + branch boxes to do the entire house vs multiple units.

Doesn't seem to save any money though and if one unit dies, the entire house is off.

Bob Bona_4

I'm taking it as the branch boxes are for extreme distance situations, intermediary stations. Run your heads direct to a multi head heat pump if you can?

Also I'm thinking space and service restrictions place the txv outside

JUGHNE

Do you cool now with window ACs? If so where are they located, how many BTU each and how well is the comfort conditions with them running.
One thing I noticed with the mini's is the circulation provided through the area. The inside fan can run constantly.....not something desirable with wall shakers.

SWEI

Watch out for turndown ratios on those multi-head systems. On larger systems, multiple outdoor units can often work out better. Residential multi-split systems are not just "smaller versions" of the commercial VRF/VRV stuff and their performance is not comparable.

Size carefully to the MJ8, and you will see that mini-duct indoor units are your friend.

ChrisJ

JUGHNE said:

Do you cool now with window ACs? If so where are they located, how many BTU each and how well is the comfort conditions with them running.
One thing I noticed with the mini's is the circulation provided through the area. The inside fan can run constantly.....not something desirable with wall shakers.

Right now all window units. 8K 16 year old Sharp in front bedroom, oversized. 6K LG, a few years old in rear bedroom, about perfect. 2 year old POS 5K in side bedroom, oversized, but not much can be done about that.

First floor is done entirely by a 17-18 year old Sharp 12K window unit in the kitchen window where I show a 12K minisplit head. This actually works fairly well most of the summer, surprisingly well. Its got a clear shot from the kitchen wall to the front of the house. It is undersized though, in really hot weather it can't keep up for obvious reasons and we ended up with 79-80F temps on the first floor which stinks, we prefer low 70s.


I've considered, and am still wondering how well a single 18K minisplit with the head mounted in the kitchen would do. My fear is, I don't know if that super quiet fan will throw air near as far as the loud window unit. If a single 18K would work there, it'd be super easy to install. I know air circulation is decent with the single window unit as not just the livignroom was 80F, the kitchen was hot as well.


One of the big reasons I'm looking into this is it seems like window units are becoming worse and worse. The late 90s Sharps I have are decent, but the later units don't fit in the windows right, are loud, etc and those two Sharp units arn't going to last much longer.


Green arrows show air path.

JUGHNE

Is your basement/crawl space open ceiling under the entire first floor?
How high does the attached carport roof go up on the 2nd floor wall.
Could you show 2nd floor window ac's and include closets?
Is that a closet in the living room (blue lines)?

I have to go do some undesirable WC repair, be back later.

ChrisJ

JUGHNE said:

Is your basement/crawl space open ceiling under the entire first floor?
How high does the attached carport roof go up on the 2nd floor wall.
Could you show 2nd floor window ac's and include closets?
Is that a closet in the living room (blue lines)?

I have to go do some undesirable WC repair, be back later.

The only, fairly easy way to the second floor, or attic from the basement is via the chase the B vent runs up. There used to be a brick chimney there so I have a little room I can snake things up, though I need to cut walls open to get in as I have it blocked between floors.

Running duct work would be an absolute nightmare on the first floor or in between floors. The second floor would be easy if everything is kept in the attic.

All walls are either plaster and wood lath, or dry wall over plaster and wood lath and house is balloon framed but there's always something in the way be it a cross brace, or blocking of some sort. I've yet to be able to snake anything even between floors without swiss cheesing the wall.

Basement is partial and only under the livingroom. There's a small area through the stone foundation to run under the kitchen into the crawl space but nothing near big enough for ductwork of any kind.

JUGHNE

Still working on the crapper from hell......
The carport roof height and 2nd floor closets??
Later.....

ChrisJ

JUGHNE said:

Still working on the crapper from hell......
The carport roof height and 2nd floor closets??
Later.....

Car port roof height, the actual shingles are about 1 foot up on the second floor. Second floor closets, there's one right by the B vent, opposite of the stairs and then one directly next to that on the front bedroom side. Rear bedroom has a closet in the back right corner by attic stairs (not shown) and one in the front right of it, both are over the kitchen.

BobC

I had a Mitsubishi 22 seer heat pump unit installed about a month ago, it's a 12k unit that is cooling just under 600 sq ft that laid out a bit like yours (open DR, LR, and Kitchen - insulated walls and windows). You right in being concerned about the throw of the fans in the wall mounted evaps, I use a fan to help move the air from the DR to the LR.

I thought about doing it myself (the install labor around here is pretty pricey) but decided it wasn't worth investing in the refrigeration gauges, micron gauge, vacuum pump, nitrogen setup for a single unit.

It's important the unit gets installed properly, that means it needs a good standing pressure test with nitrogen and a good deep vacuum down to a couple of hundred microns to get rid of ANY moisture.

From what I understand the factory flare's on the linesets are often poorly made and should be redone, it might be worth brazing instead of flaring the connection on the evaps for awkward to reach locations, that way the only leak location would be at the condenser unit.. I've also heard that a double flare is better than a single flare as far as potential leaks go.

Make sure the evap drain lines all have good slope so water doesn't back up into the wall units and down your walls. If you install units yourself any warranty is void so keep that in mind.

Bob

ratio

The factory "flares" on the lineset are only there to keep the nut from falling off! Some of them are so short that you can just about pull the nut off by hand. I always cut them off & use my eccentric cone tool to make a new flare. Makes pulling the lineset in a little easier, as I can go a little strong & shorten it up after.

Protip: use a spring bender to form them where they come out of the wall. Come out pointing towards the lines sticking out of the head. (This is on different sides depending on mfgr, size, whatever--always check!) There are a number of mini split condensate pumps that can be made to fit under the head (although it's really tight in a 9k head), so you're not limited to gravity drains.

SWEI

Depending on the loads, I'd think seriously about tucking a mini-duct indoor unit in the top of those two back-to-back closets. You could cover two bedrooms plus the open central upstairs area with a single head and about six feet of ductwork.

Put some of these in the bedroom doors.

Braze a mini-split in the wrong place and you probably lose your warranty. Airplane and spacecraft hydraulics rely heavily on flare fittings. I'll mention http://www.flaringspin.com/ again, check it out. It reams, flares, and polishes in one short step.

Techman

Sitting on the bowl reading material. Daikin University,I believe its called. Harvey Ramer has been there,ask him.

Also for more reading on the subject. ACCA has a book, "Manual Z" - Residential Zoning.w/ a section or two concerning Ductless Zoning. it is a Good Read!

For those that don't know ChrisJ look at his post count!!!!!!!!!!!!!!.

He may be a self admitted "not-a-professional" but DON'T LISTEN TO HIM!!! He is a BS artist!!!!!!!!!!! He knows A LOT!!!!

JUGHNE

If it were my job to consider, I would start with an outside unit on the kitchen end of the house. One inside unit in the kitchen blowing towards the living room..........one inside unit for the bed room above blowing towards the bedroom door.
These line sets would be both on the outside of the house and pop thru the wall right into the inside unit. There are some line set covers that don't look bad and can be painted.

Another outside unit on the "left" side of the house with a living room inside unit blowing to the right towards the B vent chase trying to get air into the living room and also to the room between liv rm and kit. That line set would sneak thru the car port on the outside of the wall.
Inside unit for the "left" bedroom with line set on the outside of the wall.
The front bed room line set could go thru the carport and pop out of the roof exposed and pop thru the wall ..........or better put the inside unit on the inside wall blowing toward the front of the house. Line set up thru the B vent chase from basement and out thru wall to cond unit. If you could come up from bsmt thru B vent chase and angle off into closet to the left of it then your evap connections would be accessible inside that closet of the other bedroom.

So 18,000 btu kitchen cond unit feeds kit & bd rm .....2 9000 btu units inside.

24,000 btu Liv room cond unit feeds liv rm & 2 bd rms......3 x 9000 btu units inside.
Total of 3.5 tons cooling....you have 2.5 now. But they will modulate to the load as needed. The smallest inside units I have dealt with are 9000 btu. This was several years ago, I have used the 3 most popular brands and at that time these were the combinations for multi-mini-splits. And you always would get the heat pump option with them. I am sure you will study the combination options as suits your needs.

All of these evap units would gravity drain to daylight so you could monitor operation and confirm condensate drainage, this will prove important in the future as the condensate flow is a good indicator of cooling factors and you can see where the water ends up.
I believe ceiling units need a small pump in the unit which is another item to be concerned about.
Any hole cut into a ceiling is another air infiltration point that no mater how careful one is will leak air.
Every air handler or duct I have put into an attic has proven to cause grief within 15 to 20 years......when something fails it then suddenly belongs to me.....no matter the time frame.

For the wall units with their short flared pigtails they are usually too short to bend down as needed. I cut off the stubs and silver solder lengths on so that I can get a bending spring on the 3/8" large line and then solder the line set on the vertical joint. Then the only flares are at the unit where they are easy to deal with should any leak.

This is what I would do just at the first glance of the job.
I know you appreciate the simplicity of a steam system and this is the simplest attack I can see for the moment.
My data on the combination of multi mini split may be out of date but things couldn't have changed that much.

ratio

If we're engineering a top-of-the-line install, check out the heat recovery systems. Think of a branch box full of reversing valves... The system can shuffle heat from where it isn't needed to where it is needed without using the outdoor coil. Neat.

JUGHNE

Not using the outside coil but the compressor only.... right?

Is there a place for this system to reclaim waste heat from a seriously overheated boiler room? (Not a residential such as Chris's but commercial application--hospital--schoolhouse etc.)

ChrisJ

ratio said:

If we're engineering a top-of-the-line install, check out the heat recovery systems. Think of a branch box full of reversing valves... The system can shuffle heat from where it isn't needed to where it is needed without using the outdoor coil. Neat.

*Drool*.
If only the wife wasn't controlling the fundage....................


That idea sounds like it would be really awesome in the winter when the oven is going a lot during holidays etc. Take that excess heat and pump it upstairs to cold bedrooms.

JUGHNE

Don't get too hi-tech, before you know it you will be recommending minis over steam.

But seriously this would be a good test sample of mini HP's covering the shoulder heating seasons. That 3.5 tons of HP would probably heat your house down to maybe 20 ODT or lower.
But as you compare the comfort from one to the other and realize the HP won't iron your blue jeans while you are wearing them like a CI radiator will.

ChrisJ

JUGHNE said:

Don't get too hi-tech, before you know it you will be recommending minis over steam.

But seriously this would be a good test sample of mini HP's covering the shoulder heating seasons. That 3.5 tons of HP would probably heat your house down to maybe 20 ODT or lower.
But as you compare the comfort from one to the other and realize the HP won't iron your blue jeans while you are wearing them like a CI radiator will.

What I don't understand is why do all of them have the expansion valves in the condensing unit? Why do you want to cool the entire liquid line often going up the outside of a house?

Wouldn't having the expansion valve in the head it self make a lot more sense? Obviously not, as no one is doing it, but what's the reason?

hvacfreak2

The single phase VRF systems that I know anything about are the S-Series Mitsu and the Samsung DVMS-ECO. Both are available down to 3 ton and both seemed to perform very well. I liked the Mitsubishi because they use the same controls as their larger systems , which gives access to all of the diagnostic information on the system. I have a few larger Samsung systems out in the world and they seem to perform incredibly well.

Harvey Ramer

The EXV is not placed in the indoor unit because of noise.

Most residential wall mount heads have about 15' of air throw. Get the model that oscillates the louvers both back and forth and up and down. That doesn't mean that you can't make a room comfortable that is wider than 15'.

You have a max lineset length for one indoor unit but then you also have a max total lineset length. You also have a max elevation change between indoor and outdoor. Probably not an issue for you. The indoor units also get derated over a certain length lineset or elevation change.

With a multisplit system it is important but not paramount to heed the minimum lineset lenght to a head. What happens if you go less than the minimum, cold will migrate up the suction line and cause condensation in the head, if it's turned off while other heads are running. Then when you turn that head on it will spit out that condensate that collected in the head. Not cool but doesn't happen if the unit remains turned on.

You won't save a cent by going with the branch box system and a single condenser. The one thing it would give you is a wider selection of indoor heads, residential and commercial.

Unless you really feel like you need to get rid of some money, I would stick with the standard Multi's

Jughne gave you a pretty good layout. i would be doing something similar. Closets are awesome for lineset connections.

It is perfectly fine mounting units on an inside wall when you are dealing with smaller rooms. When you are in bigger rooms, it's better to have them on outside walls.

When you have the option, try to locate the units in such a way that they don't blow directly at a person where they sit to relax. Some people dont mind it but a lot do. The adjustable louvers help with this as well.

Try to place the heads in such a way that they can wash the whole room when the louvers are swinging from side to side.

I personally am a Daikin fan. Seems like they take care of any issues that may come up. In this area, they have also proved to be the most trouble free. They manufacturer almost all their own components, including their patented swing compressor. Check it out.

The condensers now are designed for this climate and able to run trouble free in freezing rain situations. Some earlier models had a problem with rain water wrapping in around the air shroud and freezing as soon as the were exposed to the condensor discharge air. It would build up till it hit the fan. Easy to fix with some silicone but the problem has been addressed in the new models.

If you are in a wind area and any of your condensors are faced into the prevailing wind, you'll need to mount a wind baffle in place of the grill.

When running linesets to the outdoor unit, do not mount them rigidly to close to the connection point. You need to leave some flex there so the flare doesn't stress from unit vibration. Use the flare nuts supplied with the equipment. They are beefier and designed not to stretch during high pressure operation. Make all your own flares on the linesets. Spend as much time as you need on each one till you get the perfect flare. no shame in cutting one or 2 off and redoing them. Personally i use Nylog on both mating surfaces and the back side of the flare. Then i set my torque towards the low end of spec. Haven't had a leak yet. Knock on wood.

ChrisJ

Thank you for the great responses and all of the information. I really appreciate you taking the time to respond.

I'm embarrassed to ask this question, but with pressure from the wife, and the fact it is beneficial to the forum I'm going to.

How bad are the cheap units compared to the good ones? Specifically the no-name Chinese units often found on ebay, online websites etc.

I realize support goes out the window, but how do they perform when working?

I'm thinking they're probably a lot better than any window unit?

Harvey Ramer

How bad are the cheap units compared to the good ones? Specifically the no-name Chinese units often found on ebay, online websites etc.

I realize support goes out the window, but how do they perform when working?

I'm thinking they're probably a lot better than any window unit?

Window unit is likely better. I would question the efficiency ratings just to name one.

If you want to try one out, I would just do one single split and get a feel for it before doing the whole house.

hvacfreak2

What I don't understand is why do all of them have the expansion valves in the condensing unit? Why do you want to cool the entire liquid line often going up the outside of a house?

Wouldn't having the expansion valve in the head it self make a lot more sense? Obviously not, as no one is doing it, but what's the reason?

Noise was mentioned but also the various " sub-coolers ", "de-superheaters " , and simple bypass solenoids to arrive at a leaving refrigerant temperature. And it's always changing , Daikin EEV's have 6000 steps for example. And some of these manufacturers are not afraid to say that they want 3/4 inch insulation on their piping.

JUGHNE

I have a cheap bargain unit on the shelf in my shop. AC only. The outside unit has a Rheem logo. Simple single speed compressor.
Needed a part for the inside unit, Rheem disavowed any connection to this system. They said this was for sale in Mexico only, but it made it to NE thru a wholesaler, not even the internet.
The part was tracked down to an obsolete Haier ??sp part not available. All other components work/function, but if it "only had a brain". So I replaced it with a Misti.

I hit disagree because you will be POed in the long run.
Think of things like Chinese rad air vents, valves, etc.
The Japanese units may be built "offshore" to them, but they have their own people on site at the factory. IIRC.

ChrisJ

After talking to the wife, and perhaps getting her back on board with a project after greatly lowering my price I'm looking at a second option but really want opinions on this as like with the minisplits, perhaps there's a better and easier way.

This idea is for a typical ducted central air system

I've seen many central air systems that flat out suck and I don't want to create one. I realized my stairs fight me all winter as I watch my hot air fly up them and can actually see curtains blowing in the breeze due to the chimney effect. So, maybe I can use this to my advantage in the summer?

How would this system work out? Est size 3 to 3.5 tons. Ducts snaked down two of the second floor closes down to the first floor. I realize, it'd be better with those supplies near the outside walls and furthest from the stairs but I don't have closets there. I would also install vents in the bedroom doors, or, in the walls depending on what's easier so the doors don't have to be left open.

My thoughts are also, the houses I've seen with terrible systems always have the second floor way too hot and the first cold. Perhaps, my design offsets that keeping the upstairs cool?






I've also learned quite a bit from this thread and have been able to shave a few thousand off of the mini-split setup as well, thanks guys for the info. This is the part I love most about projects like this, learning.

My understanding of normal units like this is they're less efficient, and probably in my situation much nosier than ductless units, but they're repairable which is nice.

Bob Bona_4

No attic for ductwork/equipment?

If there was, one option is an attic system with drops down thru brs to hit first floor rooms - either via closets or boxed in corners. Or, find a chase for a riser from a basement system to do second floor rooms via an attic trunk.

yes/no?

ChrisJ

Bob Bona said:

No attic for ductwork/equipment?



If there was, one option is an attic system with drops down thru brs to hit first floor rooms - either via closets or boxed in corners. Or, find a chase for a riser from a basement system to do second floor rooms via an attic trunk.



yes/no?

Yep, open attic which is where I would install the system. That's why I have one huge return on the second floor in the common area near the stairs. It's convenient, and I think will actually work really well. But I want opinions on it.


Basement is a no, too confined, too low ceiling, impossible to get to kitchen etc.

Gordy

What about HV? Spacepak, or unico?

ChrisJ

Gordy said:

What about HV? Spacepak, or unico?

I don't know, I know absolutely nothing about such systems?

Bob Bona_4

Attic system then, with 7" drops. If you have room for 2 supply trunks to zone first/second, that would be good. Central upper hall return fine, if you're feeling good about more ceiling penetrations in the plaster go for br returns and down size the hall one. If there's attic space.

ratio

The system doesn't have to be lousy, if you don't knucklehead it. Do the heat gain calcs diligently, size the duct carefully, & a split should work fine. As for efficiency, the first time you have a $100 repair instead of a $1000 repair, you'll be in the black.

I forgot, are you planning on a heat pump or straight AC? A modern stat with a dual fuel kit may allow the system to operate from one control.

ChrisJ

ratio said:

The system doesn't have to be lousy, if you don't knucklehead it. Do the heat gain calcs diligently, size the duct carefully, & a split should work fine. As for efficiency, the first time you have a $100 repair instead of a $1000 repair, you'll be in the black.

I forgot, are you planning on a heat pump or straight AC? A modern stat with a dual fuel kit may allow the system to operate from one control.

I only need cooling, but of heat can be done for a small additional cost I wouldn't mind having it there as backup and for mild weather.

Harvey Ramer

The only way to get a 2 story house comfy for both heating and cooling is to split it up into 2 zones. The best way, a lot of times, is to do 2 systems. One for downstairs and one for upstairs.

Gordy

I'm not sure what ratio is getting at. With mini splits you can get ac only, or heat pump. The high seer ones are for the heat pump, and applies when in heating mode not cooling like 21 seer.

Either one is doable with the right calcs.

An air handler with heat capability will cost more than just a straight air handler. Negligible really.

Tim Potter

My brother in law & sister in law from STL (super hot & super muggy) have an early 1900's 3 layer brick house with steam heat. They had their a/c system installed 20 years ago, & the setup very similar to how you describe your concept. AH in the attic, all ducts & returns through ceiling, main floor drops through closets, the open stairway is the return from the main floor to the upstairs big return air grill in the hallway. I can't say I've ever been in a house that is more comfortable in the summer, it works great. The only recurring problem they have is the condensate pump clogs occasionally, & is located in a hard to get place in the attic, so make sure you have the best access possible for service. & of course, DONT OVERSIZE or your humidity control & comfort suffers greatly.

Good luck,

Tim

ChrisJ

Harvey Ramer said:

The only way to get a 2 story house comfy for both heating and cooling is to split it up into 2 zones. The best way, a lot of times, is to do 2 systems. One for downstairs and one for upstairs.

I'll be using steam for heat most of the time, if not all of the time.
Actually, I'm not liking the idea of a heat pump, if I wanted heat for this type of system wouldn't it be wiser just to put a gas furnace in the attic?

For a conventional split system I'm thinking strictly cooling is my best bet.