Aircon air vent temperature.

[HHGTTG]

Has anyone got any figures for what the temperature should be just inside the centre air vents with the aircon on and on max. chill. I measured mine with the car stationary, with the engine revs at about 1500-1800 rpm and with the fan speed on, say, 2 and a digital thermometer with the probe about an inch or so inside the vent.
The minimum temperature reached was ~ 3.9C with the outside temp. 22c but of course the accuracy of the thermometer is only +/- 1c.
I sometimes imagine that the system was much colder late last summer (took delivery in late July 2009) but I have only got the Climatic aircon system not the one where you can set you temp. for each side of the cabin.

[SammoVWT]

I wouldnt expect it to drop anymore than 3.9 as it would risk frosting the coil and vents which could cause damage - let alone thermal shock from such large temperature differences,

If its getting weaker, it may have lost a little gas charge and needs re-gassing (3.9C is pretty cold) - dont forget to factor in some of the heat will transfer as the air is moving so may appear colder than it actually is ontop of the innacuracy of the thermometer.

Edit: also most of the more sophisticated heat pumps tend to regulate around 10-13 (C) offcoil temperatures, so to get that reading i would say its probably ok

I have calculated some theoretical offcoil temperatures before at a very high fan speed of 6 degrees offcoil, typically its colder with slower air flow as more work is done on the air before passing (sensible cooling increased).

PS its not the most precise science working with air, much like sound - but the general theories hold up to a pretty accurate degree

[HHGTTG]

I wouldnt expect it to drop anymore than 3.9 as it would risk frosting the coil and vents which could cause damage - let alone thermal shock from such large temperature differences,

If its getting weaker, it may have lost a little gas charge and needs re-gassing (3.9C is pretty cold) - dont forget to factor in some of the heat will transfer as the air is moving so may appear colder than it actually is ontop of the innacuracy of the thermometer.

Edit: also most of the more sophisticated heat pumps tend to regulate around 10-13 (C) offcoil temperatures, so to get that reading i would say its probably ok

I have calculated some theoretical offcoil temperatures before at a very high fan speed of 6 degrees offcoil, typically its colder with slower air flow as more work is done on the air before passing (sensible cooling increased).

PS its not the most precise science working with air, much like sound - but the general theories hold up to a pretty accurate degree

I omitted to say that the temp. did rise to 5c or 6c as I increased the fan speed to 3 or 4.

I don't think 4c is over cold despite your comments. When Googling for information earlier, some old information regarding certain makes of car seemed to indicate that this outlet temperature wasn't exceptional and is car and system dependent.

[Keithuk]

Has anyone got any figures for what the temperature should be just inside the centre air vents with the aircon on and on max. chill.

Nice to know your name Marvin?

I've just answered your question on golfmk6.com.

We test aircon at work and I think we use an inside vent temp of 5C. For those of you that can't calculate thats 41F. Or you can use my Conversion Utility

[HHGTTG]

Nice to know your name Marvin?

I've just answered your question on golfmk6.com.

We test aircon at work and I think we use an inside vent temp of 5C. For those of you that can't calculate thats 41F. Or you can use my Conversion Utility

Yes, thanks. I'm all over the place as most of us are. Still not my real name though! Thanks for the information.

[HHGTTG]

I have made a faux pas, unforgiveable I suppose in someone with a scientific background of over 50 yrs. I forgot to calibrate my instruments!!!

Today I took my digital thermometer's probe and plunged the first 2 inches or so into crushed melting ice and to my surprise found that the stable state temperature read 2.3c and so the error here is much higher than I thought. I also remembered that I had one or two Mercury in glass 0-100c thermometers and put those alongside the probe and they read, near as damn it 0c. It was seem that my aircon vent temp. is lower than I first thought.

I used to use thes glass thermometers but it is a trifle difficult taking readings quickly when you withdraw the mercury bulb from the air vent!

[SammoVWT]

I omitted to say that the temp. did rise to 5c or 6c as I increased the fan speed to 3 or 4.

I don't think 4c is over cold despite your comments. When Googling for information earlier, some old information regarding certain makes of car seemed to indicate that this outlet temperature wasn't exceptional and is car and system dependent.

It is deemed cold in terms of comfort conditioning Also its true it is very dependant on each system, location, humidity etc