Froze Perfect Aire Mini-Split outdoor unit solid

[Tracs]

I have a 18K BTU Perfect Aire ductless mini-split system 17 seer, heat pump.

https://perfectaire.us/product/18000-btu-single-zone-mini-split-outdoor-unit-230v/

24x30 garage. In-floor heat setup and I use the mini-split as supplemental heat now and then. The outdoor temps have been 0 and -15 Celsius for the last couple months. The unit is supposed to make heat down to -15C or 5F. I turned it on and left it assuming it would turn itself on and off as needed if it got colder than -15.

We got a cold snap of -35 Celsius and I never manually turned the unit off. While in the garage I would notice it blow warm air for a bit, then go into defrost mode. I never thought much of it.

Today the indoor unit was humming (which I'm sure I've heard it do lots lately) so I went out and looked at the outdoor condenser unit. It had snow all around it and when I brushed it away I found the unit full of ice, the cooling fan blades frozen in 2" of ice. I could smell a faint burning electrical smell.

I have no idea how long the unit has been this iced up. Days, weeks, a month. I don't know.

I hoarded the unit in with a insulated tarp and have a 240V construction heater thawing it out. Temps are back around -10C. Within 4 hours most of the visible ice was melted. By tomorrow I'm sure it will be completely defrosted and dry.

I am not overly concerned about the condenser, but more the cooling fan. If is has been trying to turn fan blades frozen in ice, I would think the fan motor must be burned out?

Should I be concerned about other parts of the unit? My thoughts are its been so cold that the condenser would not have the chance to overheat.

Plans are to completely thaw the unit out, test it and if it seems to work, then shut it down until above freezing temperatures.

 

[nsula_country]

Damn.

Never actually heard of a heat pump freezing up. Literally...

Compressor probably got hot, high head. Hopefully it had pressure switches to control that.

Condenser motor was locked rotor for some time. It may be burnt. The smell is most likely from fan. Compressor is in closed circuit.

Report back after thawed, dried, and temps warm up a bit.

CT

 

[Tracs]

Damn.

Never actually heard of a heat pump freezing up. Literally...

Compressor probably got hot, high head. Hopefully it had pressure switches to control that.

Condenser motor was locked rotor for some time. It may be burnt. The smell is most likely from fan. Compressor is in closed circuit.

Report back after thawed, dried, and temps warm up a bit.

CT

It is supposed to be -8C tomorrow. If the unit is completely thawed and dried out I will give it a try. I guess I will know instantly if it works or not.

 

[justinjoyal]

It needs to be turned off manually if it doesnt have its own sensor.

Does it have a heat strip at the bottom of the condenser unit so ice doesnt build up following defrosts ?

 

[Tracs]

It needs to be turned off manually if it doesnt have its own sensor.

Does it have a heat strip at the bottom of the condenser unit so ice doesnt build up following defrosts ?

It does have a outdoor ambient temperature sensor.

Looking at the parts breakdown It does not appear to have a heat strip in the bottom of the condenser.

 

[Tracs]

Good news.

The unit completely thawed and dried out. I turned it back on and I think it started working as it should. The cooling fan motor was spinning and wasn't making any strange noise.

I ran it for about 45 minutes to make sure it was working. The ambient temp is about 14F.

The bottom 2" of condenser fins inside the unit are mangled. When it warms up I will get a fin comb and straighten them out. The bottom fins are actually touching the rear grill.

The entire condenser coil seems to be bulged out at the bottom. At the top the coil is straight across the unit, but at the bottom it bows out about 1/2" or so more than the top.

One thing I did notice is that after 45 minutes of running a small bit of frost was forming on the condenser coils. I know the unit will build up some frost/ice and then defrost. My issue came from excessive snow and defrost ice buildup.

Is it normal to get some frost on the coils at 14F? The unit has a low charge warning indicator, and that never came on.

For now I have turned off the unit. I used the unit all last winter with no problems, but we barely had any snow.

 

[Fueler]

Just last week I had the same thing happen to my 36k shop unit but it's my own fault.
A perfect storm of rain, snow and cold happened.
Water coming off the roof enveloped the unit.
To add to the aggravated ice is the drain gets plugged up and the ice just builds and builds.

I heard it moaning, shut it down, chipped the ice off of it.
Fired it back up a couple of hours later and all was well again.
This spring it gets a Cover above it to deflect the water.
Perhaps even some side vertical shields a couple of feet away on each side to deflect any wind.

On a related note, I had to make a wind break for the tube heater exhaust a while back.
It faces the north to an open 200 acre field. Even with the fancy serrated outlet cap on it sustained high winter winds would back pressure the tubes and it would not fire.

For those with tube heaters.
If you have the inlet drawing air from inside the shop and the above happens you will get a hell of a cold breeze in there quickly. My fault also. Once I understood the situation I ran inlet piping to the outside.

This should have been done in the first place. I immediately noticed a reduction in propane usage due to plugging that leak.

 

[PoorOwner]

You need a base pan heater for locations that stays below freezing for most of the day.

The defrost water drips down but it is 100% blocked by ice so it slowly builds up until it touches the fan.

I have had frost build up when ambient in the 30s in about an hour. Moisture in the air is drawn to the fins which is just a bit colder and become frost. My unit somehow knows it is supposed to defrost so it doesn't let it have frost for that long (maybe 15 minutes?) But about every 1 to 1.5 hour, it would build frost and have to defrost for about 10 minutes. Can't say my heating inside is very efficient that way, during defrost i get no heat obviously, but during frost build up the fan cannot get any air through the coils at all and the heat is very weak.

Supposedly, when it is colder than freezing the frost build up is not as bad or frequent because moisture is not collected in the air anymore. But then there is ice problem and snowfall to deal with.

 

[Fueler]

Agreed, the defrost adds to the situation.
I got curious and found this idea and am giving it a try as a full demelt.

 

[PoorOwner]

Could it be as easy to add something like this on the bottom of the pan?
just turn it for 20 mins once in a while or keep it on during extreme weather

https://www.acehardware.com/departments/heating-and-cooling/heaters/heating-cables/33511

 

[Fueler]

That might work. I have seen a version that has a flat sheet with the wires encapsulated. This would make for easy installation. I will have to look more into that. Wire it up to a switch on the wall and turn it on as needed.

When I had Satellite dishes I installed some similar heaters on them. Funny thing is that hard snow or ice did not bother them much. Still reflective would be my guess. However, Big, fat fluffy snow would knock them out in a heartbeat.

 

[Fueler]

Looked it up. Barrel heaters is what I was thinking of but they are kind of spendy. I was also thinking that we use one on the race car to heat up the oil but it's 12 volts. Some digging will likely find a version that is 120 or 240v.
MCM had this magnetic style listed which looks doable.
https://www.mcmaster.com/tank-heaters

The ace hardware type will be the cheapest way out. Take a piece of aluminum sheet, cut to fit the bottom of the unit and not block any drain holes. Drill some holes on each side of the cord, back and forth across the sheet. Tie wrap the cord to the sheet and mount on the unit.

 

[PoorOwner]

I bought a GREE (I think it is top model Sapphire, used to be Crown before)
still have to install it,
but I like that they have compressor heat (tape?) on it and the base pan heater already included.

With the Mitsubishi and Daikin you can also add the option heater, I assume it will be plugged somewhere into the PCB.

The advantage is that the unit will turn it on as needed using it's own power supply.

Technically, the compressor needs to be kept warm as well to avoid slugging because all the oil and refrigerant will be concentrated at the compressor as it gets colder. Mitsu and Fujitsu done theirs by using a bit of power to energize the compressor when it detects ambient cold enough. This "feature" activated on the bigger units and optional jumper on the smaller units. Some people really hate it because they consider it a vampire draw, but it is needed for the health of the compressor.

 

[PoorOwner]

OP, you also need to elevate the unit ideally a foot off the ground. If not, try to use paver blocks that gives you 6" from the ground.

once the defrost water hit the ice cold concrete it is ice damming due to no clearance.

 

[Jackfre]

OP, you also need to elevate the unit ideally a foot off the ground. If not, try to use paver blocks that gives you 6" from the ground.

once the defrost water hit the ice cold concrete it is ice damming due to no clearance.

This is probably the original cause of the problem. It is one thing for the unit to successfully defrost, but if the unit cannot drain off the water you end up in your current situation.

 

[Raisedonadeere]

This is probably the original cause of the problem. It is one thing for the unit to successfully defrost, but if the unit cannot drain off the water you end up in your current situation.

Airflow off the ground is better also but being above the frozen draining is critical.

 

[Tracs]

You need a base pan heater for locations that stays below freezing for most of the day.

The defrost water drips down but it is 100% blocked by ice so it slowly builds up until it touches the fan.

I have had frost build up when ambient in the 30s in about an hour. Moisture in the air is drawn to the fins which is just a bit colder and become frost. My unit somehow knows it is supposed to defrost so it doesn't let it have frost for that long (maybe 15 minutes?) But about every 1 to 1.5 hour, it would build frost and have to defrost for about 10 minutes. Can't say my heating inside is very efficient that way, during defrost i get no heat obviously, but during frost build up the fan cannot get any air through the coils at all and the heat is very weak.

Supposedly, when it is colder than freezing the frost build up is not as bad or frequent because moisture is not collected in the air anymore. But then there is ice problem and snowfall to deal with.

I have inquired with Perfect Aire if they make a direct install base pan heater, I have my doubts as Perfect Aire seems to be a economical brand. I haven't heard anything back yet. I did see that Mitsubishi offers one.

OP, you also need to elevate the unit ideally a foot off the ground. If not, try to use paver blocks that gives you 6" from the ground.

once the defrost water hit the ice cold concrete it is ice damming due to no clearance.

I will try and elevate it but am not sure how much I can move it without damaging the copper lines.

Last winter I had no problems, but we also had very little snow. This year we had a big dump and I never checked the outdoor unit out. When I had problems and finally looked, the outdoor unit had 6" of snow all around it. I think the snow is what caused my problems this year.

 

[dsimatt]

If you don't have a pan heater I'd be worried about running it in the cold, my hyper heat has one and is also a foot off the ground. I'm surprised the amount of moisture that is under mine when I run it for a few hours.

I've noticed when it's a more humid day outside my unit will do more defrost cycles, I've never had any snow build up issues to deal with.

 

[finn]

I don’t think the Mitsubishi hyper heat unit requires the optional base pan heater.

I ordered a hyper for my wife’s exercise room and a non hyper for the guest house.

The dealer installed two hyper units instead.

He said the non hyper required the heater, which brought the price to within spitting distance of the better performing hyper.

He ate any cost difference.

The hyper is working well in single digit temperatures. It will be below zero tonight, so should be a good test.

I had the unit mounted under the deck, ( daylight basement with a covered porch above ) and slapped some plywood up to control snow drifting. No snow around the unit, and we have probably 30 inches or more on the ground.

 

[PoorOwner]

I don’t think the Mitsubishi hyper heat unit requires the optional base pan heater.

I ordered a hyper for my wife’s exercise room and a non hyper for the guest house.

The dealer installed two hyper units instead.

He said the non hyper required the heater, which brought the price to within spitting distance of the better performing hyper.

He ate any cost difference.

The hyper is working well in single digit temperatures. It will be below zero tonight, so should be a good test.

I had the unit mounted under the deck, ( daylight basement with a covered porch above ) and slapped some plywood up to control snow drifting. No snow around the unit, and we have probably 30 inches or more on the ground.

The Hyper Heat / H2i can be have without the heater as well, clearly ecomfort sells it with or without
I think the model goes, FH09NAH (heater) or FH09NA (without heater)

Have you checked the presence of it and checked your name plate on the outdoor unit?

 

[finn]

The Hyper Heat / H2i can be have without the heater as well, clearly ecomfort sells it with or without
I think the model goes, FH09NAH (heater) or FH09NA (without heater)

Have you checked the presence of it and checked your name plate on the outdoor unit?

Haven’t checked, but the dealer knows the climate, and the unit is still under warranty, so I’m not too worried. There’s too much snow on the ground to trundle through to check the nameplate.

It’s 2 degrees, so we’ll see how well it works when she uses it this evening.

 

[yeldogt]

I think is was after around late 2015 that all the true low temp Mitsubishi hypers came with heaters -- it's to make sure the defrost water leaves the unit.

I'm not sure if they still make the +15 unit -- that one did not come with the heater.

You need the heater in the NE USA -- it's too cold and damp to run w/o

Mitsubishi puts an H at the end of the model number to indicate the heater is installed -- not the H in the first set (that's the hyper)

 

[Tracs]

Somewhat of a update.

I haven't used the unit since I shoveled and thawed it out. It is finally getting nicer around here. I ran the unit inside with a set point of 70F. It was 25F outside. - That is considered nice here right now....

The unit ran for 10-15 minutes then the outdoor unit went into defrost mode. A while later the indoor unit head started blowing again, but lukewarm air. I went out to look at the unit and is had a light layer of frost on it and the cooling fan wasn't spinning. I assume it doesn't need to because of the outdoor temps.

I am not 100% convinced there wasn't some damage from when it froze solid. The unit has built in leak detection and hasn't given an alarm.

Is it still too cold to be using if for heat? Am I being paranoid now? I can't say 100% how it performs compared to the pre-freeze.

Is there a calculation that can be done to verify the temperature coming out of the indoor unit is correct for outdoor ambient temp?

 

[Fueler]

FWIW. As I mentioned earlier I also had a freeze up.
We have had wild swings from dry to rain to snow and bitter cold all along.
My issue happened again so I got right on it.
I can attest in my case it was rain coming off the roof and over the gutters.
It would freeze in just the right place to stop the fan or slow it down.
Other ice buildup around the lower fins didn't seem to bother it.
Frost on the fins is no biggie. Comes and goes

As mentioned in an earlier post it will have a rain deflector over it before next winter.
Part of the ice buildup around the bottom of it is due to a plugged drain hole.
Added to my maintenance list.

 

[PoorOwner]

Somewhat of a update.

I haven't used the unit since I shoveled and thawed it out. It is finally getting nicer around here. I ran the unit inside with a set point of 70F. It was 25F outside. - That is considered nice here right now....

The unit ran for 10-15 minutes then the outdoor unit went into defrost mode. A while later the indoor unit head started blowing again, but lukewarm air. I went out to look at the unit and is had a light layer of frost on it and the cooling fan wasn't spinning. I assume it doesn't need to because of the outdoor temps.

I am not 100% convinced there wasn't some damage from when it froze solid. The unit has built in leak detection and hasn't given an alarm.

Is it still too cold to be using if for heat? Am I being paranoid now? I can't say 100% how it performs compared to the pre-freeze.

Is there a calculation that can be done to verify the temperature coming out of the indoor unit is correct for outdoor ambient temp?

Outdoor fan doesn't spin during defrost. But normally, it should.

 

[Tracs]

I just did a test.

Inside garage air was 64F with unit off for a day. Outside was 30F

After 20 minutes of running the output temp of the indoor unit was 91F measure shining a instant read laser thermometer into the output grill. The intake air is about 67F.

So far no defrost cycle yet. Outdoor unit is pretty loud though. I attached a video.

Perhaps it is working as it should.

 

[Tracs]

It just went into defrost mode after 45 minutes of running. I went outside and you could see the light layer of frost disappearing within seconds. I will see how it acts until next defrost cycle.

 

[Tracs]

So its warmed up quite a bit here and I have been testing the unit.

I think it is ruined.

In heating mode the inside garage temp started at 61F. Outside air temp was 55F. The unit will run and the inside wall unit will blow hot air (laser temp gun says outlet is about 95F) but the outdoor unit gets a heavy layer of frost in no time. The cooling fan doesn't come on.

In cooling mode the inside garage temp started at 70F. Outside air temp was 55F. The indoor wall unit will blow air that is slightly above room temp, 73F.....

The outdoor unit coil gets hot, 135F but the cooling fan never comes on.

If it is low on charge, it obviously leaked out. But if it leaked out and isn't a simple fix like a bad flare connection, that means the unit is probably wrecked internally now.

The outdoor unit has built in leak detection but this one is giving no errors. Unless enough leaked out while i wasn't in the garage and there isn't enough pressure to leak and trip a alarm?

There were periods I wouldn't go in the garage for a few days at a time while the heat mode was on.

The unit operating temperature range is:

Indoor Temperature / Cooling - Room temp - 62F-90F / Heating - Room temp - 32F-86F

Outdoor Temperature / Cooling - 32F-122F / Heating 5F/86F.

So I am well within the operating temperature range.

My Uncle is a licensed installer and he installed it and told me he will come look at it. Only problem is it takes a month of nagging on him to get him over.



Anyone offer any opinions?

 

[PoorOwner]

from what I know, the low detection only works in cooling mode on the mini's, something about the discharge temperature.

Have your uncle find the leak, it should not be too out of his realm at all, fix,
weight in new charge.

you can even put some bubbles over the flares and see for yourself first.

 

[Tracs]

from what I know, the low detection only works in cooling mode on the mini's, something about the discharge temperature.

Have your uncle find the leak, it should not be too out of his realm at all, fix,
weight in new charge.

you can even put some bubbles over the flares and see for yourself first.

I hope it is as simple as that. My concern is that it leaked when it was trying to run in February but was frozen in a block of ice and damaged the seals or something in the compressor.

 

[MattT]

In heating mode the inside garage temp started at 61F. Outside air temp was 55F. The unit will run and the inside wall unit will blow hot air (laser temp gun says outlet is about 95F) but the outdoor unit gets a heavy layer of frost in no time. The cooling fan doesn't come on.

In cooling mode the inside garage temp started at 70F. Outside air temp was 55F. The indoor wall unit will blow air that is slightly above room temp, 73F.....

The outdoor unit coil gets hot, 135F but the cooling fan never comes on.

Something is wrong with the condenser fan or the circuit running it.

 

[Tracs]

Something is wrong with the condenser fan or the circuit running it.

This is what my uncle is thinking. He came over yesterday to check it out. It has good refrigerant charge but the fan won't come on.

He is going to try the fan capacitor first and see if the motor is getting power.

 

[htmdude57]

It might not have a capacitor? It might be a variable speed motor. It might be necessary to replace the motor. You might try to see if you can download the service manual for your system, off the perfect air website.

 

[Tracs]

It might not have a capacitor? It might be a variable speed motor. It might be necessary to replace the motor. You might try to see if you can download the service manual for your system, off the perfect air website.

Outdoor unit Model is 2PAMSH18B-SZO-17.7

It does have a capacitor but the parts manual doesn't list the part number. Uncle is going to check with the wholesaler to see if he can get parts.

 

[justinjoyal]

Looks like a Midea mini-split.

From what I can tell, the unit is inverter driven. If it's the case, there's no capacitor to replace. Check the fan motor.

https://us.midea.com/dam/jcr:b1d380.../SM_Blanc(GA)_60R410A_3D INV_US_NA_170309.pdf

 

[MattT]

Looks like a Midea mini-split.

From what I can tell, the unit is inverter driven. If it's the case, there's no capacitor to replace. Check the fan motor.

Inverter driven compressor. The wiring diagrams show both single phase AC motor, with capacitor, or DC motor options for the the condenser fan. I'm guessing "DC" means ECM.

 

[justinjoyal]

Inverter driven compressor. The wiring diagrams show both single phase AC motor, with capacitor, or DC motor options for the the condenser fan. I'm guessing "DC" means ECM.

Yeah i took a quick look at it I believe the unit was available as the old on/off type or as inverter with the usual variable speed fan.

The model number provided here showed inverter operation.

 

[MattT]

Yeah i took a quick look at it I believe the unit was available as the old on/off type or as inverter with the usual variable speed fan.

The model number provided here showed inverter operation.

All the inverter minisplits I've looked closely at use either PSC AC or ECM "DC" for the fans. Are you seeing some units with inverter driven 3 phase fans?

And FWIW the manual you linked looks like the AC fan option is 2 speed.

 

[justinjoyal]

Variable speed fan motors (dc). The compressor is inverter driven.

 

[Tracs]

The fan itself has a wiring diagram for 2 speeds.

Taking the unit apart shows the capacitor.

2.5uf 450v capacitor