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Auto heating with AC Off?

6889 Views 20 Replies 7 Participants Last post by  AppleKnocke
I've spent about a year now trying to get to the bottom of this, a few times I've managed to get auto heating mode with AC switched off.

Here is the way to set it up (Kudos to all the members on RZOC who tested my various iterations of this while I was trying to work out the hack).


1. Start car.
2. Dial desired temp and press auto
3. Press AC off and wait a minute.
4. Switch car off, lock up and go away for a while.
5. Go back to car, unlock, start car.
6. Press windscreen max and then press it again.

Once in place this hack will remain persistent on restarts, you can change temp but if you press any other heating buttons it will go back to normal and you'll need to follow above process again if you want auto with AC off.

It's the delay and locking the car that makes it work. Vehicle Car Auto part Speedometer Compact car


Reason to use this hack?

Well I think it perhaps heats up a little quicker and it uses a smidge less power over a trip. but that's just my gut feeling. why not try it yourself and report back.
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Is the a/c not the heat pump in reverse to heat?
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Is the a/c not the heat pump in reverse to heat?
Exactly. The A/C is simply a reversible heat pump. In summer it pumps the heat out of the car as a conventional AC unit does. It compresses a gas in the compressor which gets hot outside the car and then decompresses it in the condenser, which gets cold and that cooling is used to cool the ventilation air on its way to the interior of the car.
Renault took this one step further. In winter the AC system is run in the same way as in summer, but the ventilation air is diverted by valves to the hot compressor and is heated on its way to the interior of the car.

I suspect the 'AC' button is a throwback to the conventional AC systems and stops the car being cooled in summer.
In regular auto mode the heatpump tries full climate control, so it may flip flop between heating and cooling. if you want it only constantly blowing warm air but varying fan speed them use my hack.
Auto mode will always be more efficient. To flip flop between hot or cold is only the movement of an internal flap to divert the air between the compressor or condenser. It also varies fan speed without any input from the driver and has already started to make the adjustments before you've thought you're getting too hot or cold. The clue is in the name, 'Auto'. :)
Your preaching to the converted. I've always said auto is best and not mess about with manual. but auto with AC off means you get a slightly warmer car for the power used, ie Zoe won't overheat and then cool as it can sometimes do in auto. ;)

It's a handy test if someone thinks they are using too much power on heating.. I saw someone recently say they used 0.8kwh in a slow 30mins 4mile commute. I'm luck if I use 0.8kwh on a full tank. :)
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That is one crazy hack! (y)(y)

For those interested in the plumbing of the A/C there is information in this document. There is an additional schematic drawing here. Switching from cooling to heating is done by closing valve 10, flipping valve 11 (both in the gas circuit) and flipping the flap connected to 4 (in the air circuit).

It should really never flip between the two in auto, that would be very inefficient. I am sure there is a bit of hysteresis implemented. The compressor, unlike many in ICE's, is also of the modulating type, meaning it can be smoothly regulated instead of a crude on/off state.
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It's a handy test if someone thinks they are using too much power on heating.. I saw someone recently say they used 0.8kwh in a slow 30mins 4mile commute. I'm luck if I use 0.8kwh on a full tank. :)
Yes, that was in auto, set at 22 deg. That's the point of climate control, auto and forget, mind you that was at-4 without pre conditioning. I leave the rest to Zoe.
Yes, that was in auto, set at 22 deg. That's the point of climate control, auto and forget, mind you that was at-4 without pre conditioning. I leave the rest to Zoe.
Here is me on a similar trip with Auto no AC. 0.1kwh for heating over 6miles, 22 degrees, 15min trip though. Vehicle audio Electronics Text Display device Multimedia
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Still impressive, no way mine would get that.
If you think the consumption meter starts off at about 3kW and then settles somewhere between 1 and 2 later on ours. That results in about half to one kWh for a 30 mins journey. I think on a longer journey it will become proportionally less, have not tried though.
Also snapped this. I've said this before, but looking at instant consumption is no an accurate indicator of power used by heater.

Seemingly suggests I'm pulling 1kW, except over that previous trip I consumed 0.1kwh.

The dash meter doesn't read in fractions. it's 1kW minimum output. and yet I only consumed 0.1kW. Had I sat longer I'd valve maybe used 0.5kW max.

It's clear to me that some Zoes go through more power than others.
Night Darkness Light Electronics Lighting
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Like Philip, I also do not understand how could AC run without AC being turn ON.? I would say only LED is ON, but everything else is the same.
About the power meter resolution. I think it changes from 0 to 1 at 500W. Still when showing 3kW it has to consume at least 2.5kW somehow.
Also snapped this. I've said this before, but looking at instant consumption is no an accurate indicator of power used by heater.

Seemingly suggests I'm pulling 1kW, except over that previous trip I consumed 0.1kwh.

The dash meter doesn't read in fractions. it's 1kW minimum output. and yet I only consumed 0.1kW. Had I sat longer I'd valve maybe used 0.5kW max.

It's clear to me that some Zoes go through more power than others. View attachment 15447
Our seems to consume more, that's for sure. Or the read outs are rubbish, yours our mine, or both.
I would not dare to fiddle with it.... as long as it works :)
It seems like I can pull roughly 800 parameters from the climate computer alone now. :sleep: I am still thinking how on earth I am going to make that into something useful. Maybe just a csv file to be picked up later on your favorite spreadsheet or something. Any creative thoughts would be appreciated.

Once we do that, a more useful comparison and "crowd diagnostic" could be tried I guess.
I suspect the 'AC' button is a throwback to the conventional AC systems and stops the car being cooled in summer.
Or the fact the panel is shared with a Clio!!!
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Or the fact the panel is shared with a Clio!!!
Haha, that would be hilarious... and worryingly believable!
Haha, that would be hilarious... and worryingly believable!
In fairness I think the timer button on the fan speed is Zoe only so my answer was a bit flippant, but the general panel is shared.
@Philip Pronto has it nailed: "A/C off" indeed inhibits the compressor to run in cooling mode, but it will run in heating mode. If you want to force no cooling but want the fans to run in summer, just set A/C off and dial the minimum temperature.

@CaptFish and @Zoe Al Of course I hear the tone of voice ;) but I don't think a shared panel with a Clio makes any ZOE part less "good". In fact, I think I'd rather have as much shared elements as possible in that respect, as I believe the Clio has far more resources to burn than the ZOE!! The somewhat buggy heater system in the ZOE, while very efficient and super-smart, also compared with other EV's is a bit Q.E.D.
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I just tried heating and cooling with AUTO mode and AC OFF mode ..... It is exactly the same. Temperature and fans are automatic in both modes... In the winter anyway, AC button has no function.
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@Philip Pronto has it nailed: "A/C off" indeed inhibits the compressor to run in cooling mode, but it will run in heating mode. If you want to force no cooling but want the fans to run in summer, just set A/C off and dial the minimum temperature.

@CaptFish and @Zoe Al Of course I hear the tone of voice ;) but I don't think a shared panel with a Clio makes any ZOE part less "good". In fact, I think I'd rather have as much shared elements as possible in that respect, as I believe the Clio has far more resources to burn than the ZOE!! The somewhat buggy heater system in the ZOE, while very efficient and super-smart, also compared with other EV's is a bit Q.E.D.
Agreed, it is silly to make a different panel for making a different panels sake.
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