Of course it did so yesterday (on a Saturday) and it's getting down to 15 tonight, -1 tomorrow, -2 Tuesday, and -10 Wednesday, so that's my "bitch". They *think* they might be able to come take a look sometime next week. In the meantime I shut it off.

It is a Carrier unit made in China (my other bitch) and installed in 2019 or 20. When it froze up the first winter the fan broke when it contacted ice that had formed and they had to order new parts including something like a defroster timer along with the fan, as well as add refrigerant.
When I talked to them yesterday I asked when they come could they please bring along the parts that will likely be needed? They said no they don't stock any parts for them so it will involve one service call to see what's needed, order whatever parts, then another service call after the parts come. They also made it clear that they were very backed up on service calls but if I feel it is "an emergency" they could schedule a "tech" to come sometime after hours but that would involve an additional emergency charge added to their regular service charge.

This unit is what heats my shop, not house, so I told them it's not an emergency just come as soon as you can. There is a 1/2 bath out there so I don't want it to freeze. When I had it built I had them install a 2' baseboard heater in each of the smaller 2 rooms so I turned them on and opened the doors. So finger's crossed. I was upset about the thing quitting again and now having to wait for who knows how long before they get it working again. But then thought really this is trivial, there are thousands in Cali who have lost their homes or apartments. And I have heat in my house, so going out now to reload the back porch with firewood.

The baseboard heaters might do a better job, just say'in.
I hate chi-com junk. Especially stuff that is considered essential.

Yeah when it gets down around 0 they're probably about as efficient. The question is can only 2, two foot baseboard strips keep a 27' x 37' building above freezing? I guess I'll find out, it is well insulated though.

The company that the builder used for HVAC handled Carrier which I thought was a good brand. I didn't think to ask where their mini-splits were sourced from, just assumed Carrier made them themselves.

The answer is no, 2 - 2' baseboard heaters will not keep your garage above freezing if it's 0 degrees outside. If you have an 8' ceiling in your garage, you'll need 40' of 240v baseboard heaters to raise 8,000 cubic feet of well insulated space 32 degrees above the outside temperature.

The good news is electric heaters are 100% efficient at turning electricity into heat. The bad news is 40' of baseboard heaters uses 10,000 watts. At $.15 a kWh, that's $1.50 an hour to run the heaters.

Thank you, trapper. I probably go pick up a space heater then and put some antifreeze in the toilet bowl and sink trap.

The bad news is I was scheduled for the repairman to come today but they called saying it's below the operating temperature of the unit, which is 10F or a little less, so they couldn't diagnose the problem anyway. Rescheduled for Wednesday the 29th when it'll be warmer.

Good news is it's staying above freezing with the two (actually 3') baseboard strips on medium and a fan circulating the air. It's up to 4 degrees out now but the sun's shinning which is helping. If I can make it beyond tonight and tomorrow night, both of which will get down to -10, I should be ok.

I'm sure glad at the last minute when wiring I had the builder put in those two baseboard strips in case the mini-split couldn't keep up, or failed. I now wish I would have had him install 2-3 more.

Nice! The above freezing part, not the repair guy not being able to do the work part.

Still doing good? I used the same calculator I used for our pole barn in TN to figure out how many btu you need for your space. We built a room across the far end of the pole barn out of 2x6s with drywall on both sides and batt insulation in between. I did find another calculator that said half the btu that I figured would be needed if it was really well insulated. That’s still a little over 15,000 btu. We have a 20,000 watt toaster in our Florida house. That’s a little over 68,000 btu which works out to be about the same btu/soft as I figured for your space.

That’s a lot of words to say I have no clue how your 6’ of heater is keeping your garage above freezing, it I’m glad it is.

quote:

Originally posted by trapper189:


That’s a lot of words to say I have no clue how your 6’ of heater is keeping your garage above freezing, it I’m glad it is.

Im guessing the shop is on a slab of warm concrete. It will eventually give up all its retained heat. At that point I bet your calculations will be correct.

quote:

Originally posted by reflex/deflex 64:

quote:

Originally posted by trapper189:


That’s a lot of words to say I have no clue how your 6’ of heater is keeping your garage above freezing, it I’m glad it is.

Im guessing the shop is on a slab of warm concrete. It will eventually give up all its retained heat. At that point I bet your calculations will be correct.

Thanks Trapper! It is well insulated with 5 1/2" foam in the walls, more than a foot over the attic and trusses, insulated slab, and only (4) windows 3' x 1'.

Reflex makes a good point that as the cold continues it would be more difficult to maintain the temp above freezing. Thankfully that 2 week cold spell is over now, it hit 36 today.

I just hope when they come Wednesday they can find the cause and fix it.

I read all of the reply’s.

Have you made sure that the air filter on the mini-split is clean?
As a temporary fix When it freezes up I believe you can run it on AC and thaw out the coils. You may have to fool the thermostat into believing a warmer temperature.
There is a defrost sensor on each unit. You may want to make sure it hasn’t come loose or been displaced to where it isn’t sensing ice?
Just my $.02.
Billy

Thanks Billy,

Yes I had cleaned the inside unit's filter about a month ago for the first time and it wasn't very dirty at all.

When I called and spoke with the company to schedule I specifically asked if I could run it in AC mode to melt the ice? He said "no I wouldn't recommend doing that, it could be hard on the compressor". That was the first I had ever heard that. I'll be here when the serviceman comes Wednesday so I'll ask him.

Again I'll ask him to show me where the sensor is. I saw what could be it today when I was able to pull off some of the ice. It was right against the coil with a wire leading from it.

When I had mine installed, they made it clear that it wasn't going to work to heat the shop in the winter. I run my gas fired heater once it gets below freezing.

Unfortunately there's no gas here totally electric. When it's 30-35 and under I heat the house with wood but I don't have a wood stove in my shop.

In my case they told me "it is rated down to 10F or a bit below" but might struggle to maintain 66 degrees when in the low teens. But it would still be putting out heat.

The lowest setting on the thermostat is 62 but anytime it's in the mid 30's and lower, I set the temp to FP or "Freeze Protect" which is 52F so it won't have to work so hard. That's where it was set during a spell of mid-30's and rain that after 2 days began dropping and turning to light snow. At that point (around 25-30 outside) it seemed to be working ok but the following day when it dropped into the teens is when I discovered it had frozen up, actually by hearing the outside fan making light contact with ice that had formed around it. I shut it off at that point.

I just have to believe something is wrong if it freezes up and quits functioning when the outside temp is within its lower operation range.

quote:

Originally posted by ridewv:..
When I called and spoke with the company to schedule I specifically asked if I could run it in AC mode to melt the ice? He said "no I wouldn't recommend doing that, it could be hard on the compressor". That was the first I had ever heard that. I'll be here when the serviceman comes Wednesday so I'll ask him.
...

With the inside temp cold, and the outside temp cold, the compressor is going to be slugging with refrigerant that is not able to easily change states from gas to liquid, and likely the evaporator will freeze up, since the same conditions exist inside and outside, in heat pump or AC mode.

The compressor is working harder than normal to compress and in some cases it is "slugging" saturated refrigerant (min gas and liquid state) when the compressor is designed to only deal with gas and not liquid.

Thanks for the explanation sigmonkey.

The serviceman came today as scheduled and at 40* outside is warm enough to thaw most of the ice out and run the unit.

The heat element in the bottom is functioning correctly.

There is sufficient charge as it's putting out very warm air inside (I forget the temperature he said it was).

He feels the problem is it was installed with a long vertical loop in the lines. From inside where it's mounted near the ceiling the lines fed down the wall, exiting at floor level to outside, then back up 3' before going horizontal behind the unit and turning down again to circle and enter the right side of the unit. That 3' rise is too much and it has created a 3' high trap which can allow oil to accumulate in cold conditions. The result of this is similar to being low on refrigerant.

Service call was $95. The cost to come back and re-route the line eliminating the trap effect would be $725.

They installed the unit as well as repaired it when it froze up that first winter under warranty not noticing the line loop trap at the time. They claim that Carrier installation instructions back in 2019 did not specify that lines could not run down then back up but more recent instructions do after they realized it could create a problem.

A wood stove installed in your building would
be great insurance for extreme cold weather
events and power grid failures.
Glad they got it fixed for you.
We had -28 F° here at my location one recent night.
I don't believe there are any heat pumps that will function correctly at that temperature.

quote:

Originally posted by ridewv:
Thanks for the explanation sigmonkey....

Glad they did you right!




Understanding the "P" trap issue was a thing I learned back in the early 90s.

Line sets should be run to ensure oil returns to the compressor both in heating and cooling (Heat pump) operation, and not collect in the line set and create "traps" of oil.