Well that isn't going to work (outdoor unit iced over)

iced98lx · January 1

we've had some bizarre weather here, between rain, snow, heavy fog, etc. Somewhere in there I wasn't paying much attention to the compressor on the northeast corner and it got about 3 inches of ice/snow on the coil. To be clear, it was still running (and heating) somehow. I'm about 15 minutes into running it in full-blast AC mode to try to melt it down, luckily I have multiple ways to heat the space so it's not much more than an annoyance.

Anything I can do to avoid in the future or just... pay attention?

WMno57 · January 1

A while back, when you joined the forum, you selected a user name that started with ICED. And now your heat pump is ICED over. What are the odds?
premonition /prĕm″ə-nĭsh′ən, prē″mə-/
noun
A presentiment of the future; a foreboding. A warning in advance; a forewarning. The act of premonishing or forewarning; hence, a previous warning or notification of subsequent events; previous information.
Do you have any premonitions for the stock market in 2024?

WMno57 · January 2

Bump for a interesting Heat Pump problem. I would really like to know if this is an inherent design problem specific to this model heat pump, or a failed part that caused the HP to not be able to handle your winter weather.
What is the Brand and Model number?
@pecmsg Do you have any thoughts on this. Thanks.

HVACNUT · January 2

No defrost?

retiredguy · January 2

Many years ago, in the 1980's I had a neighbor that had the same problem. This unit had a defect in operation that no factory service tech could fix. Consequently, the mfg gave him a 10 year 100% warranty including all service calls. In the 11th year he called me and asked for my help. Long story short, that heat pump had a bad condenser fan motor, a bad defrost timer, and a bad auto reset high pressure switch. The high pressure switch would cut off the compressor at 280 PSI which is not high enough to allow the unit to defrost. I replaced the necessary parts including the high pressure cut out and "shazam", the unit functioned correctly for the first time in 10+ years. There is a lot more to the story that puts the MFG in a bad light so enough for now. So, call a good HVAC and have that unit repaired. Having it iced up like it is will cost you a lot of money in operating $. My 2 cents.

EBEBRATT-Ed · January 2

Running the compressor with that much iced up is bad.

They say the new heat pumps will work in really cold weather. That may be true.

Who would like to go out in the snow and wind and try and troubleshoot the problem when it is below 0 the wind blowing and it is snowing.

Maybe our climate zar could do it. I would not want to,

ChrisJ · January 2

EBEBRATT-Ed said:
Running the compressor with that much iced up is bad.

They say the new heat pumps will work in really cold weather. That may be true.

Who would like to go out in the snow and wind and try and troubleshoot the problem when it is below 0 the wind blowing and it is snowing.

Maybe our climate zar could do it. I would not want to,

Better than working in an attic when it's 130-140f up there with the underside of the roof cooking you in my opinion.

GGross · January 2

I would give the unit a once over check up, make sure it is a cold temp model. I had a contractor that had this issue on his personal mini split and it was a cold temp model, it turned out he had a refrigerant leak, I didn't think it would cause icing like that but it did

JUGHNE · January 2

Do you have back up electric heater strips?

Or were you assured the you would never need back up heat in the air handler?

Obvious defrost board/sensor system failure.

Where is this located?

HomerJSmith · January 2

Put a roof over it. It's not rocket science to keep the ice and snow off the thing.

ChrisJ · January 2

HomerJSmith said:
Put a roof over it. It's not rocket science to keep the ice and snow off the thing.

Hmmm

STEVEusaPA · January 2

HomerJSmith said:
Put a roof over it. It's not rocket science to keep the ice and snow off the thing.

Yes, snow comes straight down...lol

SuperTech · January 2

HomerJSmith said:

Put a roof over it. It's not rocket science to keep the ice and snow off the thing.

I actually have a few mini splits in my area that the homeowner did just that to them. I guess those engineers never thought about the winter weather, lol.

EdTheHeaterMan · January 2

SuperTech said:
HomerJSmith said:

Put a roof over it. It's not rocket science to keep the ice and snow off the thing.

I actually have a few mini splits in my area that the homeowner did just that to them. I guess those engineers never thought about the winter weather, lol.

Why would you expect anyone with an engineering degree to think about operating a heating appliance when it is cold outside?

iced98lx · January 3

Thanks for all the comments. I think I have a lead on what is wrong.

This is a cold weather specific unit, and we really only installed them to do AC, though, we thought if the electric was cheaper, we'd use this instead of the natural gas-fired boiler that heats the house otherwise.

First: It's a 36kbtu Blue Ridge serving two zones. It does have defrost, it DOES properly run the defrost. I ran the AC for a while and it melted the whole coil down nicely, and it was warm enough yesterday that I got it really nicely cleaned up. I was quite proud of myself.

Kicked the heat back on, and it was working great!

Woke up this morning and it was iced back over!

Like many of you, I assumed there was an issue with the charge or something else. We have two of these 36k but units, one doing 3 zones of bedrooms and this one doing the living/dinning/kitchen (1200sqft open concept room with ceiling cassettes). I started looking, defrosting, checking temperatures of refridge lines...

Then it hit me, literally, a huge warm, wet blast of air from the power venter for the boiler. It's about 10ft away on the same wall and when it runs, with the wind and vegetation on that side of the house the condenser sucks up all that hot moist air and shoves it through. We hadn't had a problem all fall with this unit icing up, until it got cold enough that the areas without minisplits called for heat and the boiler had to run somewhat regularly.

I'm not ruling out a charge issue but does seem like I'm shoving hot wet combustion air through it a time or two every hour, seems logical that moisture soaked air is freezing on contact in 20 degree weather to the coil... at least to me it does!?

So for now, I'll chalk this up to failure to pay attention by the installer. (that was me, so I guess I'll take the heat)

HVACNUT · January 3

Not surprised. Where's the drier vent? That's a good one for clogging condenser coils.

WMno57 · January 3

I'm starting to think homes with heat pumps in cold climates should have a backup system.
If the house is all electric, then a backup of electric resistance. Either heat strips in the air handler, or electric baseboard. Something that is independent of the heat pump's control board (another failure point). Maybe a simple thermostat that can fail over between the two. Even if the resistance heat was undersized to keep the house at 60 on design day, that would avoid avoid frozen plumbing.
I've lived my entire life in cold climates. Maybe in the future heat pumps and all electric can be counted on to perform. Today, in theory they work, but in reality too many points of failure for me.

pedmec · January 3

Your defrost should initiate at the first sign of ice build up. You shouldn't have to manually switch it into a/c mode to get it to defrost. Make sure your defrost control is working. This is not normal operation.

SuperTech · January 3

WMno57 said:

I'm starting to think homes with heat pumps in cold climates should have a backup system. If the house is all electric, then a backup of electric resistance. Either heat strips in the air handler, or electric baseboard. Something that is independent of the heat pump's control board (another failure point). Maybe a simple thermostat that can fail over between the two. Even if the resistance heat was undersized to keep the house at 60 on design day, that would avoid avoid frozen plumbing. I've lived my entire life in cold climates. Maybe in the future heat pumps and all electric can be counted on to perform. Today, in theory they work, but in reality too many points of failure for me.

I agree with this 100%. That's why I think the current push to make everything all electric heat pumps in NY is asinine and crazy. It kills me to see customers ripping out perfectly good furnaces and boilers to install mini splits just so they can get a rebate. I have seen a few customers regret this decision already.

iced98lx · January 3

HVACNUT said:
Not surprised. Where's the drier vent? That's a good one for clogging condenser coils.

Dryver vent thankfully is quite a distance away, but this is power vent is for a 265k btu NG boiler from the 70's, so it's dumping a lot of (warm) air and a lot of moisture out right next to it. My fault for not considering the entire operating area.

pedmec said:
Your defrost should initiate at the first sign of ice build up. You shouldn't have to manually switch it into a/c mode to get it to defrost. Make sure your defrost control is working. This is not normal operation.

I agree, and it does kick to defrost within about 20 minutes of the boiler kicking on, which is when I assume it has realized it's icing up. I suspect it's being overwhelmed but will do more checking to make sure it's working as designed per the manu docs when I get time.

WMno57 said:
I'm starting to think homes with heat pumps in cold climates should have a backup system.
If the house is all electric, then a backup of electric resistance. Either heat strips in the air handler, or electric baseboard. Something that is independent of the heat pump's control board (another failure point). Maybe a simple thermostat that can fail over between the two. Even if the resistance heat was undersized to keep the house at 60 on design day, that would avoid avoid frozen plumbing.
I've lived my entire life in cold climates. Maybe in the future heat pumps and all electric can be counted on to perform. Today, in theory they work, but in reality too many points of failure for me.

I don't disagree currently, though in this case the design case was just AC, so shame on me for being annoyed when it didn't heat properly. We intentionally didn't plan to replace the primary heating option, though mostly for comfort reasons (warm toes in the winter! can't beat radiant!), but I was hoping to look into a Air to water heat pump for the radiant heat in the future. I'll have to be much more careful about condenser placement and maintenance if that ever happens.

I did intentionally position these units so they would be most protected during the summer (aka shaded/have line of sight for traditional breezes to move air) and didn't put much thought into the winter aspect outside of making sure they're above the normal snow line. The northeast corner of a house in South Dakota winters isn't the best place for anything you want to function.

hot_rod · January 5

iced98lx said:

HVACNUT said:
Not surprised. Where's the drier vent? That's a good one for clogging condenser coils.
Dryver vent thankfully is quite a distance away, but this is power vent is for a 265k btu NG boiler from the 70's, so it's dumping a lot of (warm) air and a lot of moisture out right next to it. My fault for not considering the entire operating area.
pedmec said:
Your defrost should initiate at the first sign of ice build up. You shouldn't have to manually switch it into a/c mode to get it to defrost. Make sure your defrost control is working. This is not normal operation.
I agree, and it does kick to defrost within about 20 minutes of the boiler kicking on, which is when I assume it has realized it's icing up. I suspect it's being overwhelmed but will do more checking to make sure it's working as designed per the manu docs when I get time.
WMno57 said:
I'm starting to think homes with heat pumps in cold climates should have a backup system.
If the house is all electric, then a backup of electric resistance. Either heat strips in the air handler, or electric baseboard. Something that is independent of the heat pump's control board (another failure point). Maybe a simple thermostat that can fail over between the two. Even if the resistance heat was undersized to keep the house at 60 on design day, that would avoid avoid frozen plumbing.
I've lived my entire life in cold climates. Maybe in the future heat pumps and all electric can be counted on to perform. Today, in theory they work, but in reality too many points of failure for me.

I don't disagree currently, though in this case the design case was just AC, so shame on me for being annoyed when it didn't heat properly. We intentionally didn't plan to replace the primary heating option, though mostly for comfort reasons (warm toes in the winter! can't beat radiant!), but I was hoping to look into a Air to water heat pump for the radiant heat in the future. I'll have to be much more careful about condenser placement and maintenance if that ever happens.

I did intentionally position these units so they would be most protected during the summer (aka shaded/have line of sight for traditional breezes to move air) and didn't put much thought into the winter aspect outside of making sure they're above the normal snow line. The northeast corner of a house in South Dakota winters isn't the best place for anything you want to function.

Can you move the boiler vent discharge? At least snorkle it up higher on the exterior.

iced98lx · January 9

Can you move the boiler vent discharge? At least snorkle it up higher on the exterior.

Due to it being a power vent I'm not allowed to add any pipe/snorkle after the output, I assume code-wise they're afraid of adding backpressure to the system. I've made an adjustment to some foliage in front of the boiler vent to allow the exhaust to head away from the house and not get forced over the condenser. I've turned the heat pump back on so I'll monitor and share progress. I appreciate all the suggestions and input!!

Canucker · January 9

SuperTech said:

WMno57 said:

I'm starting to think homes with heat pumps in cold climates should have a backup system.
If the house is all electric, then a backup of electric resistance. Either heat strips in the air handler, or electric baseboard. Something that is independent of the heat pump's control board (another failure point). Maybe a simple thermostat that can fail over between the two. Even if the resistance heat was undersized to keep the house at 60 on design day, that would avoid avoid frozen plumbing.
I've lived my entire life in cold climates. Maybe in the future heat pumps and all electric can be counted on to perform. Today, in theory they work, but in reality too many points of failure for me.

I agree with this 100%. That's why I think the current push to make everything all electric heat pumps in NY is asinine and crazy. It kills me to see customers ripping out perfectly good furnaces and boilers to install mini splits just so they can get a rebate. I have seen a few customers regret this decision already.

Is it because of the equipment or poor design/installation? If the same people using rules of thumb to install heating equipment are being counted on to install heat pumps, I would think you'll run into issues regardless. That doesn't make the technology inferior, it makes the installer inferior.

iced98lx · January 10

Here is a graph of the temperature on the main floor this afternoon, the heat pump ran without any icing up issues. The temperature outside hovered between 10 and 15 degrees F. I have a rule that kicks it off completely if the temperature outside is zero or below.

pecmsg · January 10

iced98lx said:
Can you move the boiler vent discharge? At least snorkle it up higher on the exterior.

Due to it being a power vent I'm not allowed to add any pipe/snorkle after the output, I assume code-wise they're afraid of adding backpressure to the system. I've made an adjustment to some foliage in front of the boiler vent to allow the exhaust to head away from the house and not get forced over the condenser. I've turned the heat pump back on so I'll monitor and share progress. I appreciate all the suggestions and input!!

The installation manual will show the exhaust details and if you can or can't extend it!

GW · January 10

WMno57 said:
I'm starting to think homes with heat pumps in cold climates should have a backup system.
If the house is all electric, then a backup of electric resistance. Either heat strips in the air handler, or electric baseboard. Something that is independent of the heat pump's control board (another failure point). Maybe a simple thermostat that can fail over between the two. Even if the resistance heat was undersized to keep the house at 60 on design day, that would avoid avoid frozen plumbing.
I've lived my entire life in cold climates. Maybe in the future heat pumps and all electric can be counted on to perform. Today, in theory they work, but in reality too many points of failure for me.

If there's an installation error (a leak on a fitting): comments like this aren't helpful. There's enough confusion regarding Heat Pumps as it is. Spitballing opinions is fine though, I guess

GGross · January 10

@iced98lx

If I were you I would do whatever is possible to make sure the heat pump is not sucking up boiler exhaust! I know it is hard, but that flue gas will wreak havoc on your heat pump over time. Good job looking out for that one too, many would miss this even when it is staring them in the face.

iced98lx · January 10

pecmsg said:

The installation manual will show the exhaust details and if you can or can't extend it!

I should have been more clear, it's a power-venter unit where the fan is at the end of the run, as such:

And I'm not allowed to add anything to the end of it according to field controls.

GGross said:
@iced98lx

If I were you I would do whatever is possible to make sure the heat pump is not sucking up boiler exhaust! I know it is hard, but that flue gas will wreak havoc on your heat pump over time. Good job looking out for that one too, many would miss this even when it is staring them in the face.

That is my mission right now, I've got control over both systems in my smart home management piece so trying to make sure they're both not running at the same time for now.

GGross · January 10

@iced98lx That is a good start, keep in mind that the boiler flue gasses will still damage the heat pump even if the heat pump is not running, but at least the heat pump isn't going to pull them into it if it's not running. Just be mindful of it if the boiler exhaust is still blowing at the heat pump

pecmsg · January 10

iced98lx said:

The installation manual will show the exhaust details and if you can or can't extend it!
I should have been more clear, it's a power-venter unit where the fan is at the end of the run, as such: And I'm not allowed to add anything to the end of it according to field controls.
@iced98lx If I were you I would do whatever is possible to make sure the heat pump is not sucking up boiler exhaust! I know it is hard, but that flue gas will wreak havoc on your heat pump over time. Good job looking out for that one too, many would miss this even when it is staring them in the face.
That is my mission right now, I've got control over both systems in my smart home management piece so trying to make sure they're both not running at the same time for now.

So, what was there 1st?
if the heater exhaust than the condensing unit gets moved. I’d the A/C then the heater exhaust gets moved.

WMno57 · January 13

EBEBRATT-Ed said:
They say the new heat pumps will work in really cold weather. That may be true.
Who would like to go out in the snow and wind and try and troubleshoot the problem when it is below 0 the wind blowing and it is snowing. Maybe our climate zar could do it. I would not want to.

News of his resignation broke today. Possible retirement gig? I'm guessing he does not own a pair of Carhartt coveralls.

Erin Holohan Haskell · January 15

Please follow site rules and do not bring up politics. Thank you.

HVACNUT · January 15

EBEBRATT-Ed said:

Running the compressor with that much iced up is bad. They say the new heat pumps will work in really cold weather. That may be true. Who would like to go out in the snow and wind and try and troubleshoot the problem when it is below 0 the wind blowing and it is snowing. I would not want to,

That's why I wandered away from commercial work. Setting up an extension ladder in 40 MPH winds to walk across a roof in 2 feet of snow to work on a gas (not heat pump) package RTU. You would pray there was one that was working so you could warm your hands on the exhaust.
And unfortunately the fuel source had nothing to do with the weather. Go figure.

iced98lx · January 15

pecmsg said:

So, what was there 1st?
if the heater exhaust than the condensing unit gets moved. I’d the A/C then the heater exhaust gets moved.

The boiler exhuast was put in first. I'll likely move the AC Compressor around the corner this upcoming summer to avoid problems.

For anyone wondering about performance, I did kick the heat pumps in for the bedrooms which uses a different compressor (same model/size properly located) and even at -15F it's keeping up in the bedrooms. I suspect it's not very effecient at these temps so I'll kick the hydronic heat back on shortly but I do want to move to a air to water heat pump for the hydronic eventually (2-5 year), so it was worth seeing how they performed on design days...

Well that isn't going to work (outdoor unit iced over)

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