Minisplit outside in Michigan winters

I know I'm a bit late to the party but thought I'd add some info for future searches. Some considerations for installing a ductless split AC system that will be running in during cold seasons:

Most ductless split systems are designed with some ability to operate at low outdoor temperatures but they all have a limit. Check with the manufacturer to see what that number is. Most have options for something called a 'Low ambient kit' to facilitate proper operation in winter.

These additions apply to normal AC systems in a ducted central air system as well.
Compressors needs a crankcase heater to keep the oil in the compressor warm and keep liquid refrigerant from migrating into the compressor during off cycles.
The condenser fan (outside unit) needs some sort of control to either slow it down or cycle it off. The fan is trying to cool the refrigerant but if its already very cold out the fan isn't needed. Over cooling the refrigerant can damage your compressor.
Sometimes turning the fan off isn't enough if the wind is blowing just as strong as a fan. This is wear wind baffles come in to shield the condensing unit from direct wind while still allowing adequate air flow when needed.
Also, if you plan to drain the condensation line from the indoor unit straight through a wall outside, you will want to heat trace it so it doesn't freeze the condensation and block/split the hose.

Mitsubishi Mr Slim P-series commercial units have an ultra low ambient system which is good to -40C/F. I'v installed these in many server rooms and they work fairly well. They are expensive though. Other manufacturers make similarly capable units.

Go go n chill said:

I always use the flare sealant! It helps on those high pressure flares.and yes keep them off the ground! The small refrigerant lines down low will freeze and bust if not. Posts pics !

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What is the flare sealant you use? What do you mean the small line will freeze and break.

Budley Doright said:

What is the flare sealant you use? What do you mean the small line will freeze and break.

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Refrigeration Technology NYLOG BLUE.
On heat pumps, when they go into defrost all of the melting frost runs to the bottom of the outside unit and onto the ground. If it isn't elevated several inches of the ground this runoff will begin to re freeze. Layers and layers of this ice eventually will incase the lower parts of the outside coil. This causes an abnormal pressure drop in the system and the thin copper will crack. It isn't covered under warranty and the manufacturer knows to look for the signs. Always keep the drain pans clear of debris. Hope this helps, I'm not the best but I'm diligent.

Go go n chill said:

Refrigeration Technology NYLOG BLUE.
On heat pumps, when they go into defrost all of the melting frost runs to the bottom of the outside unit and onto the ground. If it isn't elevated several inches of the ground this runoff will begin to re freeze. Layers and layers of this ice eventually will incase the lower parts of the outside coil. This causes an abnormal pressure drop in the system and the thin copper will crack. It isn't covered under warranty and the manufacturer knows to look for the signs. Always keep the drain pans clear of debris. Hope this helps, I'm not the best but I'm diligent.

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The nylog is more for threaded fittings like service caps, you can use it on flares but a couple of drops of oil (POE) on the flare will have the same effect and is not snot like lol, the key to a leak free flare is doing it properly but with a heat pump the expansion and contraction is an issue, they should be sweat on fittings in my opinion . As for the drain pan freezing, as stated most name brands now have heated bottom trays as an option and the baffle kit, it's not an abnormal pressure drop that causes the pipe to crack but it is the expansion of the ice. It will typically take out the fan and the fan control board as well. I'm having a rash of leaks right now from winter installs and now following installers around, showing them how to do a proper flare and proper leak test . Just installed a couple of c-can keg storage coolers and fininshed them yesterday and got a free keg, what a nice guy lol. I don't feel so good this morning lol.

Mitz all have flare fittings, and yes I follow installers around. Pressure drop, that came straight from the manufacturer. That the smaller lines will collapse on themselves. We've had several do that the first year. Our rep has told us to use the NYLOG, it's safe and it works. Yes a proper flare is important and should work, but I use it because I do not like going back on myself or someone else.

Go go n chill said:

Mitz all have flare fittings, and yes I follow installers around. Pressure drop, that came straight from the manufacturer. That the smaller lines will collapse on themselves. We've had several do that the first year. Our rep has told us to use the NYLOG, it's safe and it works. Yes a proper flare is important and should work, but I use it because I do not like going back on myself or someone else.

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i would be doubtful it's pressure drop but more the ice crushing the pipes but perhaps I'm thmisunderstanding what your saying. And all nylog does on a flare is lube the flare, same as oil but it is a Thread sealent, nothing wrong with using it lol, just that oil works as well on a flare where the seal occurs, not the thread, again it works but only as a lubricant. And yup your right about the drain holes, keep em clear. I see a lot of units on stands (2pc) where the stand is the perfect fit to cover the drain holes . 35 years as a refrigeration mechanic and I've seen it all, the good, the bad, and the ugly. Most techs now are taught more how to sell a new unit and pad the bill, very few actual refrig mech. here any more . it's really a sad thing. Every unit I go to now has a leak stop tube sitting on the ground lol.

Budley Doright said:

The nylog is more for threaded fittings like service caps, you can use it on flares but a couple of drops of oil (POE) on the flare will have the same effect and is not snot like lol, the key to a leak free flare is doing it properly but with a heat pump the expansion and contraction is an issue, they should be sweat on fittings in my opinion . As for the drain pan freezing, as stated most name brands now have heated bottom trays as an option and the baffle kit, it's not an abnormal pressure drop that causes the pipe to crack but it is the expansion of the ice. It will typically take out the fan and the fan control board as well. I'm having a rash of leaks right now from winter installs and now following installers around, showing them how to do a proper flare and proper leak test . Just installed a couple of c-can keg storage coolers and fininshed them yesterday and got a free keg, what a nice guy lol. I don't feel so good this morning lol.

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We

Budley Doright said:

i would be doubtful it's pressure drop but more the ice crushing the pipes but perhaps I'm thmisunderstanding what your saying. And all nylog does on a flare is lube the flare, same as oil but it is a Thread sealent, nothing wrong with using it lol, just that oil works as well on a flare where the seal occurs, not the thread, again it works but only as a lubricant. And yup your right about the drain holes, keep em clear. I see a lot of units on stands (2pc) where the stand is the perfect fit to cover the drain holes . 35 years as a refrigeration mechanic and I've seen it all, the good, the bad, and the ugly. Most techs now are taught more how to sell a new unit and pad the bill, very few actual refrig mech. here any more . it's really a sad thing. Every unit I go to now has a leak stop tube sitting on the ground lol.

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pressure drop or whatever .... It's not good to do. Not here to take or give a lesson.. You asked and I told you what I was told from my rep. Fact is if a hp is not on pump up it won't get warrantied Lol . I don't work on commission and have NEVER used leak stop. Bad practice you know that

Go go n chill said:

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pressure drop or whatever .... It's not good to do. Not here to take or give a lesson.. You asked and I told you what I was told from my rep. Fact is if a hp is not on pump up it won't get warrantied Lol . I don't work on commission and have NEVER used leak stop. Bad practice you know that

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Ok I'll stop giving lessons then, it's hard not to as that's what I do now, I'm an instructor at nights lol. I wasn't referring to you btw, just the trade in general . And honestly re: leak stop, it does have its uses but not unless it's a last resort in an out of warranty piece of shit that customer has no money to replace, I have used it twice in old R-22 systems and one 410 and it works like a charm actually .
NuCalgon seems to have the best success btw.

Budley Doright said:

Ok I'll stop giving lessons then, it's hard not to as that's what I do now, I'm an instructor at nights lol. I wasn't referring to you btw, just the trade in general . And honestly re: leak stop, it does have its uses but not unless it's a last resort in an out of warranty piece of shit that customer has no money to replace, I have used it twice in old R-22 systems and one 410 and it works like a charm actually .
NuCalgon seems to have the best success btw.

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No worries

I was going to put up a fence and awning around it.

Finally got them anchored into the ground. And wall units mounted. Holes drilled.

So today's the electric and wiring. Hopefully it'll all be completed.

It's 3am.

Yay lol

jayjay777 said:

I was going to put up a fence and awning around it.

Finally got them anchored into the ground. And wall units mounted. Holes drilled.

So today's the electric and wiring. Hopefully it'll all be completed.

It's 3am.

Yay lol

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Time to burn one

i am running a 18k mini split with 1 head unit in my flower room.i exchange air between my flower and veg room with 2 6 inch fans one going each way through light proof baffles.i am only running 1800 watts of led cobs in flower and 200 to 400 watts of led cobs in veg.my heat never comes on from the mini split in the winter.my dehumidifier runs more during lights out and keeps the mini having to cool even during lights out but not much .i do run fans non stop to circulate air in the rooms also.i am in sw michigan though so my temps are not as drastic.we have smart meters and i get much cheaper electric from 9 pm to 7 am so i run flower at night.i have the building well insulated and the two connected rooms insulated as well with osb for the building walls and the room walls and all ceilings.