"mini split"A/Cs

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cfz2882

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just picked up the outdoor portion of a Mitsubishi "Mr Slim"A/C system-it is brand new,shipping damaged but appears nothing important is broken.It's a pretty high-tech unit with a variable speed,inverter driven compressor and fan motor.If this checks out ok,may obtain an original evaporator unit or come up with a suitable substitute evaporator/blower/controls setup.Anybody have or know details of Mr Slim or similar mini split system?Though most of these are Japanese/Asian,I did see a De Longhi mini split(Ca.2005)and it was made in Italy.
 
I certainly haven't heard of any horror stories from such systems. Your biggest worries are "Mitsubishi Heavy Industries," which is just over-marketed, low-quality crap.

Most name-brand, non-generic systems will usually last years. Only trouble is by then, the inverter boards will probably be obsolete, and thats eventually a curse, rather than the blessing. Or, if lightning strikes, it will get COSTLY. My biggest gripe with inverters is placing all that "technology" in the outdoor unit were it can get damaged instead of in a protected box near the unit, or on the evaporator unit itself. 

 

However, I must also forewarn you, be prepared for some adjustment in the way these systems work. On a traditional Central-Air unit, you can choose the blower to shut off when the compressor stops. Well, when an inverter eventually gets the point of shutting off, the evaporator blower keeps running, and blows humidity back into the room.

These systems are also not "draft free ventilation" like most central air is. 

 

Given a choice, Central air wins ANY DAY for me :)
 
indeed,that is one of my concerns:lightning strike blowing up an expensive inverter board-i'll make sure I have decent lightning protection if I use it.Paid $100 for this unit :)If I build a substitute evaporator unit,i may make it a ducted setup more like a central air.
 
We got a new Mitsubishi inverter unit back in 2010 to replace the old one which was probably 15+ years old. It's super duper duper quiet. I swear on a stack of Bibles it is virtually noiseless outside. Even after 4 years I sometimes get drawn over when I see the fan running to see if I can hear any sound at all emanating from it.. no hum, no fan noise, no compressor noise, nothing but the rustling of some nearby weeds . I would prefer if the inside fan unit shut down with the compressor or make it optional but it's almost silent as well on normal speeds. Definitely quieter than a central air unit blowing air like I've heard in some houses. It came with a 10 year warranty at the time I bought it and was the most expensive of 3 quotes. Our is mounted on the wall above the stairwell. On the old one you could just stand on the 3rd stair and reach up and slide the filters straight down and out.. On this one the front panel has to be opened and hinges upwards, then slide them down..they bend around over the top as well.. a bit of a pain to replace after you wash them. I have to get a ladder out to do it now. It runs from something like 4700 Btu up to 23,500 or like.
 
Around here, that being South Africa, "mini split" systems are the norm and really those machines are very effective and very quiet.

We have two LG Art cool units installed in our apartment, and they are now about 10 years old, and the tennant has told us that they are still working 100%.

They are not inverter types though, what I do like about them is the heating function, they give out so much heat for half the price in elec.

Granted they do not shut off once the ambient temp is reached they do tend to dial back on the fan.

Hope your have a good cooling season with them.

Cheers
 
I wrote a patent draft for inverter-drive compressor & fan AC in the early 00s. If I'd had $50,000 for lawyers and prototypes I might have owned the entire industry.

Have to say though, living with 'intelligent' air systems (PTAC/hotel thru-wall), they can't be counted upon to be very smart. The thermostats don't seem to be calibrated to ANYthing. I have to chase temperature whether heating or cooling, and the numbers on the display bear little relationship to a freestanding thermometer in the room or to comfort.

The New World dictionary should define "halfass firmware" as one word.
 
We just had one put it two years ago

It is a Mitsubishi split system it cam installed with a two years worth of every 6 month maintenance and check out. 5 years complete repair and 10 year on the compressor. It is super quiet and I LOVE it. Like Pete said you cannot even hear it run outside either. Plus my electric bill dropped almost as much as it was financed for. I would never return to any other type of unit now. In fact planning on building a new house down this way and the design and layout will only need one unit for all the the heating and cooling. NO Duct Work...

PHilippe
 
In installed 4 Sanyo mini split systems a few years ago. They work great and the important thing is that I can zone the house. If it is pleasant weather but I want the bedroom cooler I can do that. I only have to run the units that I need. With central it's all or nothing. Another reason is that A/C is usually pared with forced air heat. I do not like forced air heat and have multiple zoned hot water. All in all, extremely happy with the mini split systems. Specs say 50db for outside units and 30db for low fan.
 
You see-or at least I have seen these split AC systems in older buildings-easy to install in them.We have like 4 of these units at the transmitter site and many,many more in the DC building where i used to work.They are good for heating and cooling battery rooms,computer rooms and our downlink equipment room.They can act as a heat pump in the winter and do quite well.I am pretty impressed with the ones at the site here.And not a wimper of trouble out of them-some are now several years old.And I have seen these put in older houses-where you can't put ductwork.And yes as some commented the outdoor condensor-compressor units don't make noise-in fact at night often see raccoons and possums hiding behind the outdoor units!
 
No ventwork

As was mentioned earlier, if ductwork is impossible, these units are a great solution. You just have to get used to this big fan apparatus hanging on the wall. Not gorgeous to look at but not too bad.
In the family there is an old farmhouse which was recently rehabbed. I pushed for a split-AC system rather than window units as ductwork was not feasible for a 100 year old building.
Alas, the building still does not have A/C.
 
Paul . . .

Assuming the house in question is 100 years old it must be on a raised foundation rather than a slab and almost certainly has an attic so it should be possible to locate HVAC equipment in those locations. I've seen old homes retrofitted with package units outside ducted under the house if there isn't room inside for an equipment closet. In the attic a fan and coil air handler takes very little room and could also be used for a heat pump. It would be worth some trouble to avoid either window units or mini-splits as both would spoil the look of such an old house.
 
You are correct

The house does have a small basement and an "upstairs / attic". That attic has two habitable rooms and a crawl-type storage area that I can "almost" stand up in.
I never thought of placing an air handler (or any other gear) in either location. The house has boiler-heat so there is no existing air-handling ductwork. You are again correct that either spot could handle some compact equipment.
I am so surprised you nailed the farmhouse with the little info I gave..
You've opened my eyes to other options! Much obliged!
 
I think the reason they don't shut off the interior fan is to keep the air circulating so it gets a realistic reading of the room and not creating hot spots before it can react, as well these units are mounted high up where it's naturally warmer. When mine is on auto mode the fan adjusts its speed quite well and when it's cool enough the fan is running on a very low setting. Still I'd like the option.
 
"Am I Reading this Correctly?"

Unfortunately, yes. 

 

The same is true for ducted units here in Australia, as well. I'm not aware of any modern system whose indoor fan will cycle with the thermostat. I think we must have an obsession with humidity or something here...

If the fan doesn't cycle, then its pointless trying to dehumidify your house on cooler, wet days. And the "Dry" mode on A/C's just turns the compressor on and off, while leaving the fan on constantly. 
 
Minni-Splits ?

They have there place, But, I agree with Hydralique they are UGLY they really spoil the looks of a house.

They are also basically throw away equipment, parts and service will be difficult or impossible when they are 10-30 years old.

The idea of continuing to run the inside fan once the compressor shuts off is ridiculous if you live in a humid climate like we have here in the DC area. A typical central unit holds more than a quart of water on the evaporator surfaces which is rapidity evaporated back into the air after the compressor shuts off if the fan continues to run.

All decent Air conditioning systems allow you to have the indoor fan cycle with the compressor for this reason.

A great heating-cooling system should never be seen or heard, it should cool, dehumidify, clean the air and heat and humidify all in one system.

Only modern forced air systems can do all this.
 
100% agree with Combo.

 

It can get humid here in Australia during the Summer, and walking into a building with Fan-On systems is just like walking into a place cooled by a Swamp Air-conditioner.

 

My friend has two of the 3-head systems (i.e. One compressor for 3 head-units). It has recently been huge trouble. They lost air-conditioning for 3 rooms in the height of an Australian Summer. The entire compressor had to be replaced. One of the head units is now leaking water everywhere - which theoretically cannot happen in a ducted system (Where the air-handling takes place in a cupboard, crawlspace and cannot spray water everywhere).

 

Old-Fashioned mini-splits were better, but were (and still are) crippled by those control boards.

"One failure, and I'm outta here" is an appropriate saying for these.

 
 
I disagree. I don't find the mini split to be ugly at all. And I would rather be comfortable when trying to sleep rather than listening to the noise of a portable A/C. My house is older and it is not possible or economical to install ductwork and a forced air system. I like my mini split system.

Gary
 
Ugly?

I don't see that these machines are as ugly or uglier than any window shaker new or old. I like the idea of the indoor unit being up and out of the way. Plus, you can still look out the window. You don't have the concern that a window unit can be an access point for a thief.

Of course, I don't have one. So I cannot comment on noise level or performance. However, when I was growing up in a house that had a window unit in the bedroom where the fan cycled, it would jar you out of a sound sleep when it did. So, perhaps the constant air movement is better in the long run.



Malcolm
 

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