Mini Split Reliability

[cqaigy2]

Have had a MRCool as primary heating and cooling the PNW US. West of the Cascades so winters are pretty mild. Some low 20F in the winter and Some 100ish F in the summer. Seems to heat and cool well. First time we've had AC, which is very nice, especially when the wild fires kick in and the outside air is unbreathable.

Had one repair last year early winter, the unit just turned on, but wouldn't do anything. No heat, no cool, not even fan on the indoor unit. Pulled the circuit board out of the outside unit an found where a slug had committed suicide. It must have been sizzling for awhile, the board developed a nice char and ate through some of the traces. Called MRCOOL tech, told him the symptoms and what i found on the circuit board, had a new board in two days. Put it in and was good to go.

 

[Kyle_in_Tex]

Thanks for all the great replies. Seems like Popgadget might have one of the oldest units talked about here.

Lots of good advice, and not many problems.

So here's another question.

2200 sq ft home. So/so insulated. All electric. I have a 4 ton central air/with a heat strip. It has to work pretty hard on humid 100+ degree days. I might have the opportunity to pick up a cheeeep used Carrier mini split. Probably about 15K Btu. It only has 1 indoor fan unit. I want to put it in my great room which is 17 x 27 and has 5 windows and the front door.

What kind of problems would it present to add a "helper" to the central air??? I would probably adjust thermostats in morning and evening to let the mini split do the most work as we spend time in the great room. Then turn the 4 ton thermostat cooler as we go to bed.

 

[Sigarms]

I have a 3 head Sanyo system in my shop that is 20 years old. It still works great.
The only issues that I have ever seen are all installer induced. Poorly executed flare connections are very common. But the equipment is very reliable. I would definitely stick with the “big” names for parts and support in the long run.

The irony is, back in the 90's, Sanyo was huge in the US market on mini splits (honestly, just as big as Mitsubishi back then IMO).

Around 2010, Panasonic basically took over Sanyo, relabeled their equipment, then a little while ago withdrew from the US market for residential applications all together.

Per Carrier, can't even keep up with who makes them now. Use to be Toshiba, someone said it's someone else now. Know about maybe 15 years ago, it was a company out of Israel. Lennox use to use Gree, now its Media. York uses Gree as well currently. Swear to God, it's hard to keep track of all the manufacturers and private lables now out because everyone is trying to hop in the US market.

 

[herm0016]

Either your boiler / radiant tubing was undersized or your mini split was oversized if a mini split could out perform a boiler for heating

Mitsubishi did a great job with that marketing term. The reality is other mini split manufacturers have the same heating performance, and in some cases outperform the Mitsubishi. No different than Carrier with Puron and hybrid heat.

When it comes to heat in very cold weather, nothing can be hydronic/radiant IMO.

1960s split level and we were under renovations, all the trim was off of the whole upstairs, including rad covers, around the windows, etc. not that well insulated anyway.

 

[hslogger]

We gotta split, mannnn. Yesterday marked the ten year anniversary of the tsunami and meltdown in Japan. We watched all the houses floating around and wondered WTH are those heating units doing at the top of the walls. Fast forward a couple years we figured they were the new mini split ductless units.

Wife looked into the techno end of it and then we called our local power company customer advisory. They came out, sat at the table and went through the options for heating and cooling and energy and dollars and cents. They evaluated our billing history and my personal firewood cutting, splitting, stacking.

They said the ductless systems are really swell and we should consider it. Ok. Up to that point we have heated with a BA Jotul and an old woodfurnace that has forced air and electrical heat back up. The whole down stairs has excellent ducting and two ducts upstairs.

I heated with wood for over forty years exclusively.

About six years ago we began installing Mitsubishi units incrementally according to dollars available and remodeling or additions. It has been great. We still have the other systems in place. When the temperature goes into lengthy teens and twenties, we fire up the wood stuff. In the summer we have air conditioning if we want it.

We now have one unit upstairs, three units downstairs. In a separate building we have one unit.

It is great technology and we couldn't be more satisfied with the units and our installers.

 

[rademamj1]

What kind of problems would it present to add a "helper" to the central air??? I would probably adjust thermostats in morning and evening to let the mini split do the most work as we spend time in the great room. Then turn the 4 ton thermostat cooler as we go to bed.

I don't see any downside to that type of use for a minisplit unit. You could see savings on your power bill, because your only cooling or heating the specific room your spending most of the time. Works best if that room can be fully isolated from rest of the house by simply closing the doors to that great room. That makes it a very comfortable family room, without needs to cool the entire house.

 

[Kyle_in_Tex]

Thanks again for the replies. I found out the unit I can get cheep is a Carrier, 18K BTU, but only at 13 or 14 SEER. The demo guys just CUT the line sets, so the freon all leaked out. Dummies. Also cut the wiring harness that communicates to outdoor unit.

Trying to figure out where to locate inside unit. It needs about 18" of vertical space, but my windows go up to 11" from edge of ceiling's crown molding.

I don't have access to attic space in the area, so can't put it on an adjacent wall.

Storms on the way tonight.

 

[Navvet]

I have had 4 Mr Cool DIY mini-split systems in operation for the last 5 years. 2 - 12k 1 - 18k and one 30k BTU and they are amazing and much less expensive than the "professionally installed systems". I'm sure prices have gone up by now but my systems cost me less than $1k per ton for 22 seer units.

If you can wire the power to these units, they are truly DIY. Completely pre-charged with quick connect type fittings, no HVAC tech to mess with.

Last month one of my 12K compressor's went bad, I called the warranty line and they shipped out a complete new outside unit via UPS. Unfortunately, UPS damaged it in transit, so then Mr Cool warranty service sent out a complete new system (third gen vice the 2nd gen I had). Other than that one issue, these units have been bullet proof, keeping our shops comfortable for 5 years now.

 

[mikester]

Two mitsubishi cold climate minisplits installed in 2017 have worked for me with zero problems down to -30oC (-22oF) and generate plenty of heat. Uses half the energy as baseboard heaters for the same amount of heat.

 

[cqaigy2]

Thanks again for the replies. I found out the unit I can get cheep is a Carrier, 18K BTU, but only at 13 or 14 SEER. The demo guys just CUT the line sets, so the freon all leaked out. Dummies. Also cut the wiring harness that communicates to outdoor unit.

Trying to figure out where to locate inside unit. It needs about 18" of vertical space, but my windows go up to 11" from edge of ceiling's crown molding.

I don't have access to attic space in the area, so can't put it on an adjacent wall.

Storms on the way tonight.

We mounted our inside unit on a wall/partition that butts up to exterior wall. Cut hole in ceiling to get access attic space feed the line set to where the inside unit is mounted. Brought the line sets thru, just clipped the edge, at an angle upward from outside, at the top plate, on into the attic space. Saved the insulation and replaced with extra as needed. Easy to fix the wall board and if you don't have texturing gun, those spray cans of pressurize texturing work ok, then a little paint.