Mini or central?

[jjrbus]

Musing this over. 8 years ago at age 70 I DIY installed 3 Daikin mini splits in the house, 2 9K and a 12K. At 4 years the 12k evaporator coil leaked and I diy replaced, at the same time a 9K pcb failed and had to be replaced by me of course.

Now 4 years later the pcb board in the same 9K unit has failed again, same as last time code L5. Due to being baffled I called in a tech who confirmed a bad board. Seems odd 2 boards. The board is custom order from Daikin and tech wants $830 to replace. Board is in the $600 for me to order, if Daikin will sell to me. I do not see me spending $830 on an 8 year old unit I paid $900 for that has already cooked one board. I suspect something damaging the boards but above my pay grade, yes I have surge protection.

2 of my units are up high 10'. They require deep cleaning once a year and at 78 I do not envision climbing ladders to clean for many more years. If I croak the wife will be unable to maintain the units and have to pay as I might have too also. Inter net search looks like a deep clean is in the $250 range per unit, 3 @ $250 is $750 a year.

So I could replace and relocate the 9K to where it is easier to service, new 9K Daikin about $1200 or 2 Whofungpoo china units for far less and have one for parts. If the 12k unit fails I could put the evaporator in a more serviceable place.

Or I could replace the central AC, 8 years ago the bid to replace the central and duct work was $6K I guess it would be over $10K today. In my experience central does not require the maintenance a mini does and there are far more techs that work on central than minis. The local Daikin dealer is a gas and go specialist who does not want to look for leaks! The air handler is in a labyrinth of trusses that is like a jungle gym getting to.

If I replace the mini I think I should replace the O rings in my tools as they have had no use and will have to check if they are compatible with the new gas's. What to do?

 

[bluedog225]

Your post is making me rethink my minisplit location. It was going 10’ up for security.

 

[manwithtools]

You can never be too secure with your Mini Split. I'd recommend either 12' or 15'. The elves in Texas keep getting bigger...

 

[bluedog225]

meth. rural.

 

[Fav Onefour]

Three units replaced with one?
I like to keep things simple.

My days are busy enough. I have twelve AC units right now. If I went against the advice of my HVAC guy I would have done a couple of those as mini splits. Thank God I listened. It would be another six units for the same buildings.
I know there is a lot of love for the mini split systems, but wait until those things start breaking down. The dirty little secret is that most are designed to last right until warranty expires. That is a lot of extra fixing if you're at 3 to 1 or higher ratios vs central systems.

 

[jjrbus]

Three units replaced with one?
I like to keep things simple.

My days are busy enough. I have twelve AC units right now. If I went against the advice of my HVAC guy I would have done a couple of those as mini splits. Thank God I listened. It would be another six units for the same buildings.
I know there is a lot of love for the mini split systems, but wait until those things start breaking down. The dirty little secret is that most are designed to last right until warranty expires. That is a lot of extra fixing if you're at 3 to 1 or higher ratios vs central systems.

I like redundancy, single unit goes out and it is an emergency. I also keep my office much warmer than the living room and the bedroom cooler than the living room.

 

[CraigStu]

Do you need to replace the ducts in the old central unit. Between myself and friends I am aware of 4 central AC replacements and none changed ducting. The installers just made up and adapter to connect the indoor unit to the existing duct.

 

[jjrbus]

Do you need to replace the ducts in the old central unit. Between myself and friends I am aware of 4 central AC replacements and none changed ducting. The installers just made up and adapter to connect the indoor unit to the existing duct.

Thanks for asking, the ducts are the flex stuff from 1986 and were installed by someone in a big hurry. One of the first things I did when I bought the house was seal up the leaks, lots of them! The air handler sits on the trusses so the drain line runs 10 feet flat across the trusses and needs to be cleaned often or overflows and drips into the closet. Raising the air handler to give the drain line some pitch should fix that. I suspect the ducts could be sized better but needs to be addressed by someone knowledgeable.

But no I do not have to replace the duct work.

 

[Fav Onefour]

I like redundancy, single unit goes out and it is an emergency. I also keep my office much warmer than the living room and the bedroom cooler than the living room.

I get the reasoning especially with zoned temps.
I've dealt with buildings that had 100% redundancy requirements for product. It's not cheap but it gives you time when a unit fails. The counter side to that is complacency. It's easy to put off repairs.

 

[finn]

Minis are essentially throw away units, but then again, most central units are too.

When I bought my 3 head Mitsubishi mini, it seemed like the best option, as there was no way practical to install ducting, given that the house has staple up heated floors.

A discussion with the same Mitsubishi dealer a few years later and he’s now recommending three separate but smaller units instead of multi heads.

My preference is still central air where practical. The filters are much larger, for one, and the installation seems cleaner.

Seems that the larger dealers in Tucson push replace rather than repair there, and push furnace replacement at the same time, even though the furnaces don’t get much of a workout, given the climate.

 

[jjrbus]

I get the reasoning especially with zoned temps.
I've dealt with buildings that had 100% redundancy requirements for product. It's not cheap but it gives you time when a unit fails. The counter side to that is complacency. It's easy to put off repairs.

Complacency, thats me!

 

[bluedog225]

Sitting here at a comfortable 75 eff with a 35 year old central unit. I’ve had to replace one capacitor. Don’t know if splits can sniff that.

 

[jjrbus]

Minis are essentially throw away units, but then again, most central units are too.

When I bought my 3 head Mitsubishi mini, it seemed like the best option, as there was no way practical to install ducting, given that the house has staple up heated floors.

A discussion with the same Mitsubishi dealer a few years later and he’s now recommending three separate but smaller units instead of multi heads.

My preference is still central air where practical. The filters are much larger, for one, and the installation seems cleaner.

Seems that the larger dealers in Tucson push replace rather than repair there, and push furnace replacement at the same time, even though the furnaces don’t get much of a workout, given the climate.

Yes minis are for the most part disposable, some of that comes from incompetent gas and go techs. Some of it from over regulation of the industry.

 

[jjrbus]

Sitting here at a comfortable 75 eff with a 35 year old central unit. I’ve had to replace one capacitor. Don’t know if splits can sniff that.

At my first house in FL it had a vintage AC unit put in by a previous owner who was an AC contractor. I looked at the unit and decided it was time to replace. Asked a neighbor who worked for an AC warehouse what to do. He told me not to touch it until it failed and then try to get it repaired. It was like 35 years old at the time.

 

[manwithtools]

Sitting here at a comfortable 75 eff with a 35 year old central unit. I’ve had to replace one capacitor. Don’t know if splits can sniff that.

And with the money you have spent on elctricity for that outdated ineffecint unit, you could have bought three new efficent mini's.

 

[bluedog225]

And with the money you have spent on elctricity for that outdated ineffecint unit, you could have bought three new efficent mini's.

I still think of it as my new air conditioner. Time flies.

My electric was $54 last month.

 

[manwithtools]

My electric was $54 last month.

How do you manage that in climate like Texas? That seems ridiculously low. How big is your house?

 

[bluedog225]

Around 2000 ft.². I put a lot of cellulose in the attic. New windows years ago. Energy efficient unit for its time. Protected from the western sun. Set it warmer at night and turn it down when I leave. It will be higher when it really warms up.

They managed to screw me on the bill with every other fee they put on there

 

[jjrbus]

And with the money you have spent on elctricity for that outdated ineffecint unit, you could have bought three new efficent mini's.8

8 years ago a ball park figure for mini splits was $10000 to $12000. No way they would have saved me money over an old inefficient unit!

 

[manwithtools]

8 years ago a ball park figure for mini splits was $10000 to $12000. No way they would have saved me money over an old inefficient unit!

Okay...

 

[bluedog225]

Maybe a Friedrich window unit?

 

[jjrbus]

Maybe a Friedrich window unit?

I have a LG dual inverter window unit in my RV and would be very happy with it in the house. However they do not come with heat and I do use heat on rare occasion. I might use the heat 15 or 20 times in the winter and the electric bill barely goes up heating with the minis.

 

[stickshift]

Minis are essentially throw away units, but then again, most central units are too.

My old central AC is 40yrs old and dying (leak somewhere, maybe the coils, so it's a little low on R22). Trying to decide - replace with inverter style central air unit or go with multiple minisplits. I've heard from HVAC techs that new central air units can be expected to last 10-15yrs, and that there's no chance they will last 30-40 yrs. So if it's all disposable, maybe go with minisplits and get that hyper efficiency, hyper zoning, and not have ducts in a hot attic.

 

[dcg9381]

Maybe a Friedrich window unit?

Those aren't built here anymore.. Not like the good old days.

Or I could replace the central AC, 8 years ago the bid to replace the central and duct work was $6K I guess it would be over $10K today. In my experience central does not require the maintenance a mini does and there are far more techs that work on central than minis. The local Daikin dealer is a gas and go specialist who does not want to look for leaks! The air handler is in a labyrinth of trusses that is like a jungle gym getting to.

I think this is right. Central AC is more "serviceable" but if you had that unit installed 8 years ago, that unit would be non-compatible with modern refrigerant, parts would not necessarily be available, and in the case of a leak or major component failure, they all want to sell you a new system... I know because I'm dealing with this on a 5 year old central AC system that is 2 months out of "parts warranty".

The units themselves might last 10-15 years, fans, caps, all the stuff replaceable, but when they changer refrigerant types all bets are off.

If I replace the mini I think I should replace the O rings in my tools as they have had no use and will have to check if they are compatible with the new gas's. What to do?

I just went out and got a new set of gauges. I'd dig for a ebay board... Of the 7 ductless installs I've been involved with in the last 4 years, only one of them has had a major failure. But they are much more "disposable" than modern central AC.


How long does a "deep clean" take you? $250 sounds high if it's a no-special tools job.... I assume this is just cleaning the filters and spraying off the coils, flushing it all down the drain?

 

[stickshift]

Of the 7 ductless installs I've been involved with in the last 4 years, only one of them has had a major failure. But they are much more "disposable" than modern central AC.


How long does a "deep clean" take you? $250 sounds high if it's a no-special tools job.... I assume this is just cleaning the filters and spraying off the coils, flushing it all down the drain?

Are the failures with ductless mostly with the head units? If so, I imagine head units can be purchased separately? I guess the hassle is pulling a vacuum and recharging refrigerant?

I've seen videos of HVAC techs using "bib kits' to deep clean head units.

 

[dcg9381]

Are the failures with ductless mostly with the head units? If so, I imagine head units can be purchased separately? I guess the hassle is pulling a vacuum and recharging refrigerant?

Seem to be board failures. In the case that I'm talking about there was some sort of leak on the evaporator coil and that's a "do over".
There are so many models and variations of compressors and head units, I've never priced one, you're probably going to spend 50% or more the cost of a whole new system and have zero warranty on it.

 

[aggie113]

My old central AC is 40yrs old and dying (leak somewhere, maybe the coils, so it's a little low on R22). Trying to decide - replace with inverter style central air unit or go with multiple minisplits. I've heard from HVAC techs that new central air units can be expected to last 10-15yrs, and that there's no chance they will last 30-40 yrs. So if it's all disposable, maybe go with minisplits and get that hyper efficiency, hyper zoning, and not have ducts in a hot attic.

I have mini splits on one side of the house where it's useful to control rooms individually. I have a ducted heatpump that replaced a traditional HVAC compressor on the other side of the house. It's a Mitsubishi hyperheat unit that combines the heatpump with a coil/blower inside a closet that takes regular filters. Improved efficiency and less maintenance than a minisplit. It helps that I have metal ducting in the attic and not the flimsier plastic they can use sometimes.

 

[jjrbus]

How long does a "deep clean" take you? $250 sounds high if it's a no-special tools job.... I assume this is just cleaning the filters and spraying off the coils, flushing it all down the drain?

You do not need manifold set for mini install, at least I will not be using mine.

I am an old guy, deep clean takes me long time. I did see a pro on youtube who can do a deep clean including removing the blower wheel in an hour! Time varies on brand, some are horrible to remove the wheel!

Believe it or not $250 for a deep clean is reasonable. Net search shows up to $400.

 

[stickshift]

I have mini splits on one side of the house where it's useful to control rooms individually. I have a ducted heatpump that replaced a traditional HVAC compressor on the other side of the house. It's a Mitsubishi hyperheat unit that combines the heatpump with a coil/blower inside a closet that takes regular filters. Improved efficiency and less maintenance than a minisplit. It helps that I have metal ducting in the attic and not the flimsier plastic they can use sometimes.

I'll have to look into this Hyperheat unit. Seems like you solved a similar problem/layout. I like the idea of individual minisplits for the bedrooms so everyone can tailor the temp to their liking. And the LR/DR/kitchen could be served by one large unit, and this is also the side of the house with the compressor, and I have rigid metal ducts in the attic that maybe I could use with something like the Hyperheat.

 

[stickshift]

I am an old guy, deep clean takes me long time. I did see a pro on youtube who can do a deep clean including removing the blower wheel in an hour! Time varies on brand, some are horrible to remove the wheel!

Check out some videos on Youtube on using a bib kit. No need for disassembly.

 

[jjrbus]

Are the failures with ductless mostly with the head units? If so, I imagine head units can be purchased separately? I guess the hassle is pulling a vacuum and recharging refrigerant?

I've seen videos of HVAC techs using "bib kits' to deep clean head units.

2 mother board failure on outside unit and one coil failure on head unit. Head unit was not available so I replaced coil. If I had to hire done would be cheaper to toss unit and replace.

 

[dcg9381]

I am an old guy, deep clean takes me long time. I did see a pro on youtube who can do a deep clean including removing the blower wheel in an hour! Time varies on brand, some are horrible to remove the wheel!

Yea, I dunno how to do that... I'd just spin it, spray it off, call it good.

 

[jjrbus]

Check out some videos on Youtube on using a bib kit. No need for disassembly.

I have done it both ways and have the kit with the tiny HVAC pressure washer. At times the wheel is so dirty is better to remove and clean. Also depends on brand, my Daikins while not easy to remove are not miserable to take out.