HVAC me please

  • Thread starter Thread starter Brawndo
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Brawndo

Brawndo

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With the weather turning, would someone be willing to decipher the Mini HVAC for me? The Motorer's Guide isn't all that great.

I assume most efficient way of heating the cabin is Auto mode. On my car, I can adjust fan speed when on Auto, which in my opinion, isn't really auto. Turning it off Auto only adds the selection of which vent(s) air comes out of. Is this normal?

My car will occasionally switch the AC on. Is this the heat pump? Is the heat pump like a house heat pump where it just runs the AC circuit backwards (aka efficient)? Should I be switching this off or not?
 
I'm no expert but I daily drive with the AC always ON and set the heating at 18 deg C with Auto ON. Occasionally I turn on the recirculation when driving in tunnels or similar. It turns itself OFF after about a minute. My Mini is the Essential version with only the most basic accessories.
 
Somewhere in the -4F range the auxiliary resistance heater kicks in as the refrigerant compression efficiency is just not there (has to be cooler to be heated by outside air).

Roughly speaking, a household heat pump should have an additional exterior condensate drain that tends to ice dam in cold climates. The MINI SE uses a chiller that is more like a fridge/freezer to avoid the icy mess. This is generally the way with the exception of Tesla and their octovalve system.
 
I run with Auto on 100% of the time, and I find it does very well. But I love the feature which maintains the auto temp but allows you to adjust the intensity by turning the fan higher. I like to feel air moving.
 
teslarati97 said:
Somewhere in the -4F range the auxiliary resistance heater kicks in as the refrigerant compression efficiency is just not there (has to be cooler to be heated by outside air).
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My real-world experience is the resistance heater comes on at a much higher temperature. The heat pump seems to lose effectiveness below 40 ºF and by 20 ºF it seems it's all resistance heating. There isn't any way to know from the cabin controls, though. That would have made a nice dash indicator, like the seat warming lights.
 
Puppethead said:
My real-world experience is the resistance heater comes on at a much higher temperature. The heat pump seems to lose effectiveness below 40 ºF and by 20 ºF it seems it's all resistance heating. There isn't any way to know from the cabin controls, though. That would have made a nice dash indicator, like the seat warming lights.
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You're probably right. I was thinking about the household heat pump with a backup gas furnace.

It's about 14ºF-20ºF when the MINI switches to resistance heating. Last week, the temps dropped to -20ºF overnight and I was averaging about 2.6mi/kWh with all creature comforts!
 
teslarati97 said:
You're probably right. I was thinking about the household heat pump with a backup gas furnace.

It's about 14ºF-20ºF when the MINI switches to resistance heating. Last week, the temps dropped to -20ºF overnight and I was averaging about 2.6mi/kWh with all creature comforts!
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LAST WEEK?!?!?!?!

You might want to consider moving towards the equator.
 
JonR said:
LAST WEEK?!?!?!?!

You might want to consider moving towards the equator.
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Yes, last week was some freak polar vortex. Over 1 foot of snow and I lost solar production for 15 days!

Usually there is one week of a polar vortex around Jan/Feb when overnight temps dip below -40ºF. Usually when it's below -25ºF, it's a good time to throw a pot of boiling water into the air.

 
Matt007b said:
That is a very good question I've always wondered how to do that... anyone know?
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I don't think you can in most of the F-series generation for BMW/MINI. Some models did have a sync button. Haven't checked Bimmercode, but I honestly rarely change the temps.
 
I appreciate that they're separate because my copilot usually wants it a little warmer than me, but I really wish they could be synced when I don't have a passenger. I've never seen a way to do it, unfortunately.
 
JonR said:
LAST WEEK?!?!?!?!

You might want to consider moving towards the equator.
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Jeezus. We dipped into the 20s last couple of nights and I’m wondering how I’ll cope when it gets near zero in late December… -20°F… in… November??
 
SameGuy said:
Jeezus. We dipped into the 20s last couple of nights and I’m wondering how I’ll cope when it gets near zero in late December… -20°F… in… November??
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Should be fine with the tires. I've seen snow in every single month of the year so I'm really not surprised. As for the R3 vs R5, I think the R5 EU label is 67dB which is quieter than the R3 72dB but sacrifices some grip.

I've gone as low as 20F in RWD summer tires once in September...didn't enjoy that!

r3r5tire.webp
 
It is different here now in NZ, it is getting hotter here, averaging 22 - 25C, can’t imagine what summer will be like.

The AC on our SE has been acting up again on the drivers side, i.e. the right side. Warm air was coming out. I used a temperature meter to measure the warm air coming out, it was 28.5C on the vent near the door and 27.6 on the other vent; but the AC temp was set to 16C.

The passenger side i.e. the left side of the car was perfect at 18C.

Will be booking it with the dealer to have a look.

Could just be the freon needing a top-up

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IMG_8857.webp
IMG_8851.webp
 
azausa said:
The AC on our SE has been acting up again on the drivers side, i.e. the right side. Warm air was coming out. I used a temperature meter to measure the warm air coming out, it was 28.5C on the vent near the door and 27.6 on the other vent; but the AC temp was set to 16C.

The passenger side i.e. the left side of the car was perfect at 18C.

Will be booking it with the dealer to have a look.

Could just be the freon needing a top-up
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If one side is working then I expect the problem is with the valve that controls the cooling on the other side.
 
chrunck said:
I appreciate that they're separate because my copilot usually wants it a little warmer than me, but I really wish they could be synced when I don't have a passenger. I've never seen a way to do it, unfortunately.
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The Ford I had before the Mini would re-sync the two whenever “auto” was selected. Then the passenger would follow the driver settings until you manually changed the passenger setting. Simple and intuitive interface.

I find myself adjusting both to the same temp when I change them so they aren’t fighting each other.


Sent from my iPhone using Inside EVs
 
Brawndo said:
My car will occasionally switch the AC on. Is this the heat pump? Is the heat pump like a house heat pump where it just runs the AC circuit backwards (aka efficient)? Should I be switching this off or not?
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I've wondered about this as well. When I'm heating the cabin, what does the AC button do? Is it a way to activate/deactivate the heat pump? Or is the heat pump being used either way and the AC button helps dehumidify or something?
 
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