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Zoe Devotee
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There is a point where the heating is great.... and that's when outside temps drop to low single digits. Why? My guess is the small ptc heater is engaged at that point to generate some heat for the heatpump to play with. When outside temp is 9-12 degrees it just does its best with heatpump only. One of the reasons I'm not so concerned about the MG have only a PTC, yup it won't be as efficient ,but it may well be more effective across a wider temp range.
 

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Discussion Starter #42
Thanks for the feedback all :)

@Sandy – I wonder if there's a way to trick the car into thinking it needs to use the PTC heater, even if it may be less efficient?
 

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Speak, Eevee!
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AFAIK the PTC heater is always-on (though it's only a tiny thing that is only any use for freezing conditions). I remember the DSG chaps mentioning such when I asked about mine taking mine a while to defrost. I do suspect though that like with that problem where you have to hold a warm rag over the temperature sensor and let it cool again to get the heat pump to flip to the right direction, sometimes the software has a bit of a glitch - mine genuinely seemed to fix itself when they looked at it early in the year, I don't know if some observation effect / something plugged in during testing came into play.

I do find in my Q210 that it works better if you select a temperature 2-3 degrees higher than you would normally. i.e. home or office I would choose around 21c but in the Zoe that is cold, seems comfortable at 23, both when its doing ac on a hot day and heat on a cold morning.

Thanks.
Yeah might give that a whirl. It does work fine to be fair, it raises the temperature.. .it's just a gentle process directed at your feet, not a wave of heat directed at your face.
 

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Zoe Devotee
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Thanks for the feedback all :)

@Sandy – I wonder if there's a way to trick the car into thinking it needs to use the PTC heater, even if it may be less efficient?
freezing cold face cloth wrapped around the outside temp sensor (or the drivers side door mirror)?
 

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Discussion Starter #45
So the Zoe was dropped into our local Renault dealer the other week ... and yep there was NO refrigerant in the air conditioning system!! ?Who'd have thought it, on a brand new car! ?

After re-gassing, the car, unsurprisingly, heats much more effectively and isn't nearly so noisy! Hopefully it will be more effective at cooling next summer too ...

Now, onto Renault Customer Support to get some kind of goodwill contribution from them for wasting my time having to put a BRAND new car straight into a garage! ?

(A relieved) David ?
 

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Co-author of CanZE. Q210 nov 2013
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Keep a keen eye on it. I am sure you didn't mean it like that, but I doubt the car was rolled off the production line ungassed. There might be a leak and regassing it is what we call "mopping the floor with the tap still running". And yes, if it is permanently fixed, it will cool VERY effectively in summer.
 

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Discussion Starter #47
Keep a keen eye on it. I am sure you didn't mean it like that, but I doubt the car was rolled off the production line ungassed. There might be a leak and regassing it is what we call "mopping the floor with the tap still running". And yes, if it is permanently fixed, it will cool VERY effectively in summer.
Yes we will do. Although they did say they did a nitrogen leak test and it came back that there were no leaks ... so fingers crossed we won’t have any further issues ,,, unless a big stone punctures one of the pipes of course! Is the air conditioning radiator right at the front as on other cars?

Many thanks,

David ?
 

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Co-author of CanZE. Q210 nov 2013
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Yup, the big one is for the heat pump. Related: the Q models have a smaller one behind it that is used to cool the motor and electronics. The R models have the motor air cooled (see the black plastic piping on top), but I am not sure if it still has a small second radiator to water-cool the power electronics.
 

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I'm not crazy, the attack has begun.
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Yes we will do. Although they did say they did a nitrogen leak test and it came back that there were no leaks ... so fingers crossed we won’t have any further issues ,,, unless a big stone punctures one of the pipes of course! Is the air conditioning radiator right at the front as on other cars?

Many thanks,

David ?
A nitrogen leak test?

How could they possibly sniff out a nitrogen leak?
 

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Discussion Starter #50
A nitrogen leak test?

How could they possibly sniff out a nitrogen leak?
??‍♂ ... I'm just pasting what it says on the invoice for the work (which was obviously covered under warranty)! Maybe they have nitrogen-trained sniffer dogs? ?

The silver lining to all this hassle is I managed to get a £100 voucher to use against future services / parts from Renault Customer Services – so I'm happy now! ?

David
 

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I'm not crazy, the attack has begun.
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??‍♂ ... I'm just pasting what it says on the invoice for the work
I've no doubt that you are.

... is this some new technique, or just typical UK incompetence?
 

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A nitrogen leak test is a common way of checking aircon for leaks. The expensive refrigerant is replaced with cheap dry nitrogen at pressure, then it's left for a number of hours before checking the pressure hasn't dropped. If all is ok the nitrogen is removed with a vacuum pump and the system is then filled with refrigerent.
 

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I'm not crazy, the attack has begun.
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That's really a very cheap way to do it and I think can only show gross leaks. I can't see it will show the micro-leaks that are the usual causes. That's why the conventional approach is to add UV tracer, which leaves a tell-tale at any leakage points.

Good luck with that!
 

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I have a feeling that there are quite high expectations for Zoe's cabin heating/cooling system. As far as I noticed, Zoe ZE20/40 does not have "climate control" and so the expectation that the ventilation system will do that is not warranted. Using the Auto function for the ventilation system is sadly merely a "preferred setting" that takes into account only the ambient temperature, but not humidity or any other variable. It can be 2C in the car, but humid, which leads to feeling warm on the skin, or it can be 7C and very dry air, which can be bone-chilling (like this morning) - these two situations are not differentiated by the ventilation system in current Zoes; I kind of gave up on the "Auto" function and just use the fan speed control both in summer and winter.

ZE50 will come with single-zone climate control (optional for lower trims, standard for top trim), which will likely have air purifier and humidity control.
 

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I'm not crazy, the attack has begun.
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As far as I noticed, Zoe ZE20/40 does not have "climate control"
What do you mean by 'climate control'?

This is where you set a temperature which software (or in older days some thermostatic system) then interprets, rather than set an amount of heating power. If only it was the latter in modern cars, at least if there was a choice to do that we'd all be a lot better off when it gets its software-knickers in a twist.
 

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That's why the conventional approach is to add UV tracer, which leaves a tell-tale at any leakage points.
UV tracer can tell you where any leaks are - if you're lucky enough that it leaves enough of a trace and it's somewhere you can find it - but positive and negative pressure tests are how the system can be proven to not leak in the first place.

The pressure measurements can be very precise and over whatever period of time you like so they should have no difficulty finding even small leaks.
 

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I'm not crazy, the attack has begun.
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The pressure measurements can be very precise and over whatever period of time you like so they should have no difficulty finding even small leaks.
I am utterly unconvinced by that.

They can either test at the low pressure running condition, around 30psi, or the high pressure 250psi. If they run low then they won't test the high pressure losses, and if they test high then they may damage the thin aluminium parts in the low pressure side (have to be thin like that for heat exchanger efficiency).

Also, the leak may be from thermal expansion/contraction issues during operation.

The only way to test properly is, surely, to look for leaks during system operation?

A pressure drop my give a hint at a gross leak, but if you were to test at 30psi and you have a leak which loses 0.05% per day (20% drop in a year) then the equipment will have measurement resolution accurately to 0.007psi?!

The temperature during the test would only have to go up by 0.05% and the test would be swamped with thermal effects on the test gas itself. That'd be an ambient change of only 0.15 degC Are they really controlling their workshop and the condition of the test gas to an accuracy of 0.15degC!!....? pfffftttt ..... I call BS.

I can see it is a gross leak test, but cannot at all see that it does anything to look for long duration leaks.
 

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We're talking about a test performed by a garage when you take your car in for them to look at, so what more could they do? Surely there just isn't a way to find leaks smaller than what the low / high pressure tests can do given a garage cannot run it for a long period, either to test the pressure afterwards or to spend ages searching for any tracer stains. What can they do that passes your "cheap and incompetent" test?
 

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I'm not crazy, the attack has begun.
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What garages have done for decades. Refill with a uv tracer and go back a few weeks later after running the ac.
 

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Co-author of CanZE. Q210 nov 2013
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Testing and refilling nowadays is most often a fully automated process. They hookup their gear, press a button and there we go. To be honest, my opinion is that in essence, this is a good thing. The process is standardized and repeatable and handles waiting times nicely on it's own. Having said that, each test has it's own issues
  • a vacuum retention test is sort of hit two flies in one stroke approach. The system needs to be emptied, and since we do that anyway, let's see if the pressure rises to detect a leak. A test like this will find a simple crack, but often not a broken seal, as those are "squeezed" when the system is vacuumed. AFAIK broken seals are far more common than "simple" leaks.
  • nitrogen pressurization is much better, but it can only tell you there is a leak, not where it is. And it will probably miss a very small leak. Think in terms of the system going empty in a few months. It's a sort of litmus test, no more. AFAIK (again), nitrogen pressure tests don't use dye.
The best method is dying the coolant and let the customer return after a week. Still, the inspection with UV light, which is VERY sensitive, might be horrific as a leak can be present somewhere deep down in the cabin section. Don't ask how I know (no, not in my ZOE). The problem is it almost always wastes at least one extra costly regas only to find the leak, and as said, a sometimes tedious inspection.

Like most issues (A/C, interference, blown up PEC, etc) they are not the norm at all, but unfortunately they do happen.
 
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