On a basic non-climate control air con system, like the one in our Colt, does it make any attempt to compensate for the temperature of the incoming air? That is, will it work harder in the current hot weather to try to keep the outgoing air cold?
Mrs F commented that it didn't feel as cold the other day, and I suspect that's because the incoming air is warmer. Just wondering whether it might need re-gassing (or whatever it is they do).
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Try the re-circulate and cool the already cool air.
Recycling hot air is not recommended.
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Possibly yes. Many modern cars use a variable output ac compressor which will adjust the cooling efficiency according to demand.So you don't need freezing cold air if the ambient temp is 16 degrees.However ,current temps would mean the ac system is working full load ,so any inefficiency in the system will be felt.Possibly the gas charge in the ac system needs checking.
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I think it must be variable. Certainly it's a bit weird that even on our latest model Jazz, the a/c still does does that 'old-fashioned' thing of clunking on and off every few seconds, the Colt doesn't do that and indeed it's not obvious when it's on - we didn't realise until some way into ownership that it comes on (without any indication) when the airflow is aimed at the screen (or a couple of clicks either side).
Ours seemed to work OK and then suddenly became very noisy last summer, at 6yrs old, with a loud hissing / screeching noise which is apparently the fluid boiling. Got it recharged and that sorted it.
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You can rest assured that your aircon has been designed for considerably hotter and more humid climates than the UK ever experiences.
By comparison, last summer we had 47C and the aircon (climate control) on our Golf was able to keep the interior of the car pleasant without running at full fan speed although I imagine the compressor was working at full tilt.
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I only have data for some Citroen models but I suspect that most aircon systems are similar.
Xantia and XM air temp at center vents should be 8 deg C in 15 deg C ambient, rising to
13 deg C in 30 deg C ambient.
So the air con temperature output rises with ambient. In 30 degrees C ambient 13 deg C still feels "cold".
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That is, will it work harder in the current hot weather to try to keep the outgoing air cold?
And I'd have said no. Think of a fridge, where you hear the compressor cutting in and dropping out to maintain a steady temperature. In warm weather, it simply is running for more of the time. I think climate control keeps the compressor running but mixes the cold air with heated air to produce the requested internal temperature.
My information may be out of date, but I remember American Fords of the 1990s having buttons marked 'AC' and 'Max AC'. Not sure whether the Max button switched on a second compressor but it was mighty effective, even in a Texas summer.
Out of curiosity, I once set the CC dials in the LEC to blue (the lowest marked temperature is 16°C) to see what would happen. What happened was that I got very cold, surprisingly quickly, so I gave in and turned it back to 19.
I'm back after a couple of weeks away, and drove the S60 yesterday for the first time in a while. Mrs Beest had set the dials there to blue, presumably thinking that would cool the interior faster. It doesn't - the book explains that there's only one compressor and it can't work any harder.
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Max ac in an American car usually means re circulation in European cars.No car uses 2 compressors ,unless it is one of those 100 ft long limos.On a car with cc,depending on what and how new a model,the temp is regulated by hot/cold blend flaps and variable load compressor operation.The click in/out ac pump is old technology,but it worked fine,but noticeable on low power cars as it would drag down engine power.hth.
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My Mazda 6 has three settings - no A/C, "A/C" and "A/C ECO" settings. This in addition to having a separate "recirc" button, so you can run recirs in A/C and A/C ECO modes. I have no idea what the difference is between the latter two A/C settings. They seem to deliver the same results. It's a slightly maddening set up, the ventilation. Just about the only thing I don't like about the car. But it's not a biggie.
The manual for the car provides no (comprehensible) explanation.
Last edited by: Alanović on Mon 28 Jul 14 at 11:28
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>> And I'd have said no. Think of a fridge, where you hear the compressor cutting
>> in and dropping out to maintain a steady temperature. In warm weather, it simply is
>> running for more of the time.
>>
Well, that's the point. That's an on/off system, as cars with a/c clutches (like our Jazz) use.
Most car use clutchless a/c compressors so they run all the time.
>> Mrs Beest had set the dials there to blue, presumably
>> thinking that would cool the interior faster. It doesn't - the book explains that there's
>> only one compressor and it can't work any harder.
>>
It probably does work harder it it's not one that is clutched.
I think this is pretty good: www.youtube.com/watch?v=DPuYF0eNK6M
Last edited by: Bill Payer on Mon 28 Jul 14 at 13:56
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>> That is, will it work harder in the current hot weather to try to keep
>> the outgoing air cold?
>>
>> And I'd have said no. Think of a fridge, where you hear the compressor cutting
>> in and dropping out to maintain a steady temperature.
Yes but no but.
Our Liebherr fridge freezer is an oddball maybe (local domestic appliance man reacted last week as if I'd asked him to mend a Renault and I had to get their service man out). Needed the "air sensor" replacing.
It's an evaporator type (gurgles gently, with the odd farting noise) and when it goes outside its range an alarm goes off and I have to adjust the setting. At the moment it's getting too cold at night, and too hot in the day.
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Thanks for all the responses. I think we'll just keep an eye on it for now - pretty sure it's ok, or good enough anyway.
Regarding BP's comment about his 'clunking' Jazz - our V reg Accord used to do the same, but neither the Focus (Y reg) or the Colt (07) did/do. Perhaps it's a Honda thing.
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>> Thanks for all the responses. I think we'll just keep an eye on it for
>> now - pretty sure it's ok, or good enough anyway.
>>
I think regular 2yr "servicing" of a/c, as dealers always tell you to do, is a scam, but if the car is 4 or 5yrs old it's probably worth getting it recharged next time you see one of the £30-£40 special offers.
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12yo Volvo system has never been recharged and can still induce a shiver when required. I don't think any dealer has ever offered to interfere with it, either.
Just a thought: intending no disrespect to the Colt, but it's a small car that probably isn't fitted with AC at all in most of its markets, so I wonder if the UK importer fitted the smallest compressor it could find, knowing that it would only occasionally - as in the last couple of weeks - be found wanting.
Last edited by: WillDeBeest on Mon 28 Jul 14 at 15:21
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Makers fit the same compressor whatever the market.However,they may fit a larger coolant rad and condenser for hotter climates.In the 80s and 90s,Mercedes with ac would be fitted with larger coolant rad and extra cooling fans,even for the European market.
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>> Just a thought: intending no disrespect to the Colt, but it's a small car that
>> probably isn't fitted with AC at all in most of its markets, so I wonder
>> if the UK importer fitted the smallest compressor it could find, knowing that it would
>> only occasionally - as in the last couple of weeks - be found wanting.
>>
It's got a little engine (1.1 3cyl) and lot of glass too, but the a/c in ours worked remarkably well and no deterioration in performace was noted until it suddenly started make strange noises. Recharging restored its performance.
I know Colt is popular in Australia, but it has 1.5L engine there and could well have different a/c components.
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The job of the compressor is just to make the evaporator cold, and the cars electronics then just keep this temperature at somewhere around 2-4 degC. This is done by either switching the compressor on/off, or varying the output (although some compressors have their output managed mechanically).
The user or the CC then determines whether or not to add heat after the evaporator to get a comfortable cabin temperature.
The biggest heat load is the sun coming through the windows, and this is fairly consistent wherever the car is in the world, so manufacturers don't usually make any country specific changes to the system
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>> The biggest heat load is the sun coming through the windows, and this is fairly
>> consistent wherever the car is in the world,
errrr
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My daughter lives in the Caribbean - she keeps the A/C permanently on Recirculation and goes made when staying over here because I refuse to do so (little or no fresh air introduced into the vehicle).
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air con temperature - Falkirk Bairn
