Air con needs looking at

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For those who have had to have their cars air con seen to, have you tried one of those mobile air con companies? If so, would you recommend them? I'm always short for time, and by the time i finish work, im assuming most places would be shut, so it would be ideal if i could get someone to come round and re-gass the ac. Does anyone know of such a company in London who are good?
 
I have had my car looked at 3 times now by a local company, who also do home/work visits in the local area. Each and every time, not had a single problem with it :)

Of course you'll get some bad ones, but I'm sure someone you know will have used someone and can recommend them! ;)
 
They don't charge if they can't cool your air con down by 10%. How on earth does this work? 10% of 22º would take the temperature down to -7.5º!!

The only thing it could be is that they beat the ambient/internal difference by 10%, i.e. if it is 30º outside and the car can cool the inside to 16º then they'll give you back money if they can't get it to 14.6º

EDIT > http://www.kwik-fit.com/about-air-conditioning.asp

"Let Kwik Fit recharge your Air Con while-u-wait for only £44.95. We will replace and recharge lubricant and refrigerant levels in line with your manufacturer’s recommendation. If we cannot improve the coolest vent temperature from your car by more than 10% - then you pay nothing at all."

So yeah - everyone get down to kwik-fit for free air-con service. 10% of the vent temperature on an absolute scale is LOADS. You simply can't take a percentage of a centigrade scale! Could definitely have them on false advertising. Stupid llamas.
 
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Ex-RoNiN said:
22degrees - 10% = 20degrees :confused:

You can't take a percentage of a centigrade scale. Also nowhere does it even say they use centigrade as a unit. The advert states that 'if we can't cool your air conditioning down by at least 10% we'll give you your money back'. Thermodynamically 10% of a temperature can only mean in absolute terms.
 
laissez-faire said:
They don't charge if they can't cool your air con down by 10%. How on earth does this work? 10% of 22º would take the temperature down to -7.5º!!

The only thing it could be is that they beat the ambient/internal difference by 10%, i.e. if it is 30º outside and the car can cool the inside to 16º then they'll give you back money if they can't get it to 14.6º

EDIT > http://www.kwik-fit.com/about-air-conditioning.asp

"Let Kwik Fit recharge your Air Con while-u-wait for only £44.95. We will replace and recharge lubricant and refrigerant levels in line with your manufacturer’s recommendation. If we cannot improve the coolest vent temperature from your car by more than 10% - then you pay nothing at all."

So yeah - everyone get down to kwik-fit for free air-con service. 10% of the vent temperature on an absolute scale is LOADS. You simply can't take a percentage of a centigrade scale! Could definitely have them on false advertising. Stupid llamas.

Whiskey Tango Foxtrot, over
 
Akira said:
No, but to get it free you would need a resulting temp of 19.8, not -7.5?

22 degrees is about 295K on an absolute scale. 295 x 0.1 = 29.5. 22-29.5 = -7.5º .

To prove how stupid and meangingless their argument is - think of a 10% reduction of the imperial units (not temperature) 72 - 10% = 64.8º which is only 5/8ths as much of a drop as you would get taking percentages of a centigrade scale. You simply can't do it. If you want to take 10% of a temperature you simply have to use an absolute scale!

It would be like "hmm, my speed relative to that car on the motorway is 2m/s since he is travelling at 40 m/s and I am travelling at 42 m/s. I am going to reduce my speed by 10%" Now... would his reduced speed be 37.8 or 41.8?
 
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laissez-faire said:
22 degrees is about 295K on an absolute scale. 295 x 0.1 = 29.5. 22-29.5 = -7.5º .

To prove how stupid and meangingless their argument is - think of a 10% reduction of the imperial units (not temperature) 72 - 10% = 64.8º which is only 5/8ths as much of a drop as you would get taking percentages of a centigrade scale. You simply can't do it. If you want to take 10% of a temperature you simply have to use an absolute scale!

It would be like "hmm, my speed relative to that car on the motorway is 2m/s since he is travelling at 40 m/s and I am travelling at 42 m/s. I am going to reduce my speed by 10%" Now... would his reduced speed be 37.8 or 41.8?

I don't get your point...Kelvin is C+273, but the "distance" between the temparatures are the same, i.e. 1K = 1C, only the base is different (Kelvin starts at 0, C at -273)

Since air cons work in C, not in K, you use the C scale, so 10% of 22 are 19.8.
 
laissez-faire said:
To prove how stupid and meangingless their argument is -

Well, it's not an argument as such, simply a condition for getting the regas for nothing. To a geek, yes it's technicaly incorrect. To the majority of the population who have no concept of absolute temperature or know what a Kelvin is, it makes sense.
 
Ex-RoNiN said:
I don't get your point...Kelvin is C+273, but the "distance" between the temparatures are the same, i.e. 1K = 1C, only the base is different (Kelvin starts at 0, C at -273)

Since air cons work in C, not in K, you use the C scale, so 10% of 22 are 19.8.
So what if I brought in an American car which had the air con in Farenheit?
22C is around 72F, so would they then need to improve it by 7.2F? (which is 4 degrees C)

Not using an absolute scale makes absolutely no sense, I'm sure a geek could go in there and demand their money back because they only improved things by a few degrees :p
 
Haircut said:
So what if I brought in an American car which had the air con in Farenheit?
22C is around 72F, so would they then need to improve it by 7.2F? (which is 4 degrees C)

Not using an absolute scale makes absolutely no sense, I'm sure a geek could go in there and demand their money back because they only improved things by a few degrees :p

Finally someone else sees the light. It isn't about being a geek - it is about things making sense.
 
bandit said:
go to kwik fit.

I'd rather be flogged than let these muppets anywhere near my car!

They have a hard enough time fitting tyres properly let alone messing around with aircon :eek:

HEADRAT
 
laissez-faire said:
22 degrees is about 295K on an absolute scale. 295 x 0.1 = 29.5. 22-29.5 = -7.5º .

To prove how stupid and meangingless their argument is - think of a 10% reduction of the imperial units (not temperature) 72 - 10% = 64.8º which is only 5/8ths as much of a drop as you would get taking percentages of a centigrade scale. You simply can't do it. If you want to take 10% of a temperature you simply have to use an absolute scale!

It would be like "hmm, my speed relative to that car on the motorway is 2m/s since he is travelling at 40 m/s and I am travelling at 42 m/s. I am going to reduce my speed by 10%" Now... would his reduced speed be 37.8 or 41.8?

Why are you using the kelvin scale when you could use the rankine scale to get even lower temperatures

20 C = 293.15 K = 527.67 R

so 10% of 527.67 is 52.77 that gives a lovely -32.67 C

Please go to kwit fit and ask for that, I am sure they will oblige
 
Ring Peace said:
Why are you using the kelvin scale when you could use the rankine scale to get even lower temperatures

20 C = 293.15 K = 527.67 R

so 10% of 527.67 is 52.77 that gives a lovely -32.67

Please go to kwit fit and ask for that, I am sure they will oblige
Umm, no. If you're using an absolute scale it makes no difference what units you use.

527.67-52.77 = 474.9 Rankine, which is 263.8K - exactly the same as if you'd worked it out just using Kelvin.

You can't just subtract the Rankine temperature and give the result in C.

(Only on OcUK could a thread on air con regassing go off topic this much!)
 
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