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What's the highest temp reading you've seen

Posted: Mon Jul 19, 2021 10:07 pm
by Beanee687
Ok it's hot this week so what's the highest temp you have seen so far on your outside air temp gauge (OAT).
Mine is 30.5C southern Hampshire 8 miles inland.
Note that even at that temp my Aircon cabin temp has not needed to be put lower than 19.5C. to keep me comfortable.

Highest I ever saw was 52c but that was in Kuwait in summer of 1981. That's hot.

Re: What's the highest temp reading you've seen

Posted: Tue Jul 20, 2021 6:47 am
by routemaster1
I think this will depend on whether the car has been parked or whether you have been driving. It could be up to 10 degrees higher in direct sunlight.

EDIT: Was this recorded in a Citroen? Just asking because all of the Citroens I've ever owned only recorded the temperature in whole numbers.

Re: What's the highest temp reading you've seen

Posted: Tue Jul 20, 2021 8:59 am
by srperry
35 degrees on Sunday standing in the sun - only went down to 32 degrees while driving around 10 miles...

Re: What's the highest temp reading you've seen

Posted: Tue Jul 20, 2021 12:37 pm
by Airtool
Very high temps in Wales 41 on screen, got terrible sunburn.sorry about dust.

Re: What's the highest temp reading you've seen

Posted: Tue Jul 20, 2021 3:59 pm
by Beanee687
I see you used your loaf.

Putting your Aircon down to max low doesn't make it produce colder air. It just makes it run longer. So long as the required temp is lower than the OAT it will produce max output. As I said mine stays on 21c most of the time. Yes put the fan on max and select recirc but no need for LO

Re: What's the highest temp reading you've seen

Posted: Tue Jul 20, 2021 9:22 pm
by the2ems
Beanee687 wrote: Tue Jul 20, 2021 3:59 pm I see you used your loaf.

Putting your Aircon down to max low doesn't make it produce colder air. It just makes it run longer. So long as the required temp is lower than the OAT it will produce max output. As I said mine stays on 21c most of the time. Yes put the fan on max and select recirc but no need for LO
Sorry, I can’t agree with that.

Re: What's the highest temp reading you've seen

Posted: Tue Jul 20, 2021 11:06 pm
by Beanee687
The system when switched ON works as follows.
How does air conditioning work?
Ok so here’s the science bit. Inside the air conditioning system is a compressor which contains a refrigerant – this is a gas. When the air conditioning system is switched on, the gas travels to a condenser. Fresh air from outside the vehicle passes over the condenser and the temperature of the gas drops quickly and causes the refrigerant to liquefy. Now in liquid form, a drier removes impurities before reaching a thermal expansion valve which essentially allows the driver to control the temperature in the car by limiting the liquid flow. Lastly the liquid is turned into vapour as it travels through evaporation coils and is then blown into the cabin as cool air. Meanwhile, the refrigerant, now back in gas form, returns to the compressor to start the process all over again.

Now the control. The temperature dialled up is compared to the temperature sensed inside the car while the required is lower than the actual the system run at it max capacity. When the temperature is reached the compressor will be declutched and the evaporator due to outside sir padding through it starts to warm when the internal sensor senses inside now warmer than out the compressor is energised and the system gets cold again. If the system gets too cold then the sir flow is diverted through the heater matrix and warned. The heater diverter flap is modulated by the sensor to give the required temp in conjunction with the compressor control. Outside or internal (when on recirc) air ALL passes thru the evaporator and then either thru or around the heater matrix depending upon the position of the diverter flap.
The compressor output is dependent upon its size and when running runs at its max output.

Re: What's the highest temp reading you've seen

Posted: Wed Jul 21, 2021 7:37 am
by the2ems
Whatever the science says, when I put my air con on low, it blows out cold air. Setting the temperature control to 21° and putting the fan on full, will not cool the inside of the car.

Re: What's the highest temp reading you've seen

Posted: Wed Jul 21, 2021 4:10 pm
by the2ems
the2ems wrote: Wed Jul 21, 2021 7:37 am Whatever the science says, when I put my air con on low, it blows out cold air. Setting the temperature control to 21° and putting the fan on full, will not cool the inside of the car.
Actually, I tried it this morning, on auto, and at 18°, with an outside temperature of 35°, and it was quite acceptable. :shock:

Re: What's the highest temp reading you've seen

Posted: Wed Jul 21, 2021 7:18 pm
by Beanee687
Today whilst out I tried an experiment
I set my system on Auto at 21. The OAT was 27.
After a while I took the temperature of the air coming out of the vents. It was 10c. I then reduced the temp to Lo and the vent temp changed by a small amount to 9.1. But after a few minutes it rose to 15c because the evaporator froze and the compressor declutched so the system could unfreeze.

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