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        General >> Problems >> air con vent temperature
        
(Message started by: pedropedro on Sep 4^th, 2007, 9:27pm)

Title: air con vent temperature
Post by pedropedro on Sep 4^th, 2007, 9:27pm

I am puzzled by the issue of vent temperatures...after regas and deep vac the best mine will do is 5-7 degrees with an ambient of say 25 degrees. I thought that was on the high side but dont see how to improve..some folk here are saying they get vent temps down to -1....thought the deicer cut the pump when evap got down to zero ...and there was expected to be another 3 degreees picked up on way to vents

i dont want to get into the override switch mod ..just would like to know why one person can get 2 degrees or better...maybe the blender leaks across...when i restart mine after a journey it blows out hot air for 20 secs...is that normal,,,any feedback would be appreciated

john

Title: Re: air con vent temperature
Post by Snoopy on Sep 5^th, 2007, 8:16am

The vent temeperature is dependant on the outside ambient temeperature, as shown in the graph on the AC pages.... HERE (http://www.fordscorpio.co.uk/aircon.htm)

With regards the warm moist air after left standing . I experience that for a few seconds and it is due to the drier refreezing after defrsoting, and is quite normal IMHO.

Title: Re: air con vent temperature
Post by pedropedro on Sep 5^th, 2007, 8:37am

thanks for that ; I have been through that link but appreciate your passing it on.

It's just i would like to lower the vent temperature and i saw in the thread re 57 code on the climate control unit......petehull quoted -1c vent temperatures after a new comp/ drier

Title: Re: air con vent temperature
Post by Snoopy on Sep 5^th, 2007, 9:38am

The drier receiver does eventually get to the stage where is is no longer effective and I suppose if it replaced then the system will work better. Perhaps consulation with a refrigeration engineer would give you more info.

Title: Re: air con vent temperature
Post by pedropedro on Sep 5^th, 2007, 10:03am

Yes will do that ...tks

Title: Re: air con vent temperature
Post by peteHull on Sep 5^th, 2007, 1:31pm

Hi Pedro

I did a check on my vents temps this lunchtime, this is a link to a photo of the results.

http://groups.msn.com/fordscorpio-co-uk/fordscorpioparts.msnw?action=ShowPhoto&PhotoID=143

Note -4.3c

I am of the opinion that the aircon system should be considered as 2 seperate systems ie the refrigerant part involving the cooling components and the control part, all the electronic components of the auto climate control system.
I considered that if I changed the main components of the refrigerant side of it then the control side would be able to work correctly as I was haveing all sorts of problems. I had interchanged components of my 10year old 2ltr car and had not been able to solve anything, it appears that I must have been barking up the wrong tree as the system runs fine now apart from on a really long journey when the fans are running but there is no cool air comming from the vents.

I found that if I turn off the aircon for 10 mins or so it all goes back to normal. Imo it could be that it is Too efficient and is freezing up the evaporator. (if I did this while parked up there was a pool of water shortly after)

Anyway, I will sort that out one day, in the meantime I end up shivering as I drive home from work....

hth Pete

Title: Re: air con vent temperature
Post by pedropedro on Sep 5^th, 2007, 2:25pm

Hi Pete

thanks for going to the trouble of taking the picture and replying

I am very jealous of the low temp you are getting, but suspect for a minus 4c temperature the deicer switch may be caput or a mod has been fitted. when you lose air thats because the evaporator has frozen up....normally deicer switches are set to switch at zero for yours to get down to -3 the core/evaporator temp must be -7 i guess..anyway thanks for the info ..john

Title: Re: air con vent temperature
Post by peteHull on Sep 5^th, 2007, 3:16pm

Yes john, that is my diagnosis too, I will get round to buying the switch new, 'cos again, I have second hand ones but I am beginning to not trust S/H electrics anymore....
May do the mod too as it looks to be a good simple project within my interest range....

pete

Title: Re: air con vent temperature
Post by Snoopy on Sep 5^th, 2007, 4:52pm

I also suspect that your de ice switch is faulty or defunk if you get no air on a long drive then it DOES signify your evap is freezing up and THAT can be fatal for the whole system.

Title: Re: air con vent temperature
Post by peteHull on Sep 5^th, 2007, 9:22pm

on 09/05/07 at 16:52:34, Snoopy wrote:

I also suspect that your de ice switch is faulty or defunk, ........ THAT can be fatal for the whole system.

Hi Snoopy,
Thanks for that, could you clarify the fatality due to overfreezing please.

Pete

Title: Re: air con vent temperature
Post by jonnycab on Sep 5^th, 2007, 11:29pm

on 09/05/07 at 21:22:49, peteHull wrote:

Hi Snoopy,
Thanks for that, could you clarify the fatality due to overfreezing please.

Pete

Tongue sticking to lips & eyeballs freezing over }{

Title: Re: air con vent temperature
Post by Jim on Sep 5^th, 2007, 11:47pm

The pollen filters also apear to have an affect on the temperature from the a/c. I changed mine last week and there was an appreciable drop in temperature from the vent. Of course it may just have been that the weather had cooled.

Title: Re: air con vent temperature
Post by Snoopy on Sep 6^th, 2007, 7:35am

ITs all in the a/c pages about what happens whe the system freezes

Title: Re: air con vent temperature
Post by peteHull on Sep 6^th, 2007, 9:02am

on 09/06/07 at 07:35:04, Snoopy wrote:

ITs all in the a/c pages about what happens whe the system freezes

So is it safe? well the worse thing that can happen if you were to run things way too cold, which we don’t intend to and which the current mod is not capable of, is that the evap fins would freeze and air flow would reduce, and if that happens you would simply turn off the A/C and the ice would thaw and drain away. Don’t confuse this with frozen pipes etc, it is the external evaporator fins condensation that is freezing and not anything internal. Having asked this crucial safety question to over twelve A/C pros, every one of them says that even if everything freezes solid there is no problem with damage. However even saying that we do not intend to run anywhere near those levels which anyway results in blocked airflow which results in no cooling in the cab which defeats the object of the modification.

This is the section I was reading.

I also have the manual from H.A.L in Doncaster where my son did the course for air conditioning, it says pretty much the same thing.

I will do some more experimenting when I have the time cos I enjoy the learning thing on these cars.... One of the reasons I value this site and everyones opinions.

Thanks again everyone and keep it comming... :D
Pete

Title: Re: air con vent temperature
Post by Snoopy on Sep 6^th, 2007, 9:48am

If the refrigerant starts to freeze then thats when problems can be caused . It can damage the compressor AFAIK and understand but I am sure that it would be most notceable

Title: Re: air con vent temperature
Post by scorpio_man on Sep 6^th, 2007, 12:00pm

hi there

re the above regarding running the system so cold it begins to freeze.

damage will occur if the system is ran too cold for too long. burst seals (mainly in the compressor), jammed expansion valve, very cold water around your feet if the drains aren't clear, etc. :o

it's all to do with the return pressure/temp. the temp pick up to the vents can be a lot more than 3oC. if you look at the a/c guys gauge, it shows what temp the return gas is at a given pressure.

the system was designed to run to about 4oC and then cycle the compressor. this setting works fine if you know how to use it.

i take it most of the issue is how quickly it lowers the temp inside the car when you get in? have you got it on rec (it sometimes does this itself)? if it's on fresh air, you have to chill the 'new' fresh air over and over. if set to rec, it just chills the already chilled air in the car again, thus reducing the inside temp quicker. when the inside temp is more comfortable, then switch to fresh air.

another point is economy. running the compressor for extended periods uses for fuel.

hth