Air con temperature fluctuates?

[983]

another air con problem....

on my 2010 fiesta, I noticed the air coming from the vents isn't very cold. 

So I used a kitchen probe to get an accurate reading from the centre vents.

 

During the recent warm weather, during the day it was coming out at about 13 degrees whilst idling.

But I've tested it at about 6pm today, outside temp was 17, and the air con was quite steady at around 7 degrees whilst idling. 

then I upped the revs to 1500, 2000, and 2500 respectively.

 

What I noticed was as the rpm rose, the temperate rose to about 8 degrees, but then once I held the throttle steady, the temperature then came back down to 6.8 degrees. lovely and cold.

but I cant get this nice low temperature during the day.

 

it has recently been topped up with refrigerant.

I've watched the compressor, and the clutch seems to be working, although it does come on and off I noticed during the warmer temperature, but it was constantly on when I took the 17 degrees evening reading.

The low pressure pipe feels lovely and cold, and you can see the condensation. 

the fan is working perfectly well.

 

whats thrown me is its not working properly when the weather warms up, if it was consistently abnormal id have it in the garage as soon as.

[iantt]

i dont see what your issue is? what was the outside temp in warm weather? its not a case of air cooling to 7-8c regardles of outside temp. its more a case of degrees of cooling from  the outside temp , 30c outside 20c inside, 20c outside 10c inside , 17c outside 7c inside. etc

[Trewithy]

With temp control set to cold, air distribution set to dashboard vents, and all the vents closed  except the one being measured I can get down to 7 degrees by varying the fan speed at tickover with the ac on. 

[983]

19 hours ago, iantt said:

i dont see what your issue is? what was the outside temp in warm weather? its not a case of air cooling to 7-8c regardles of outside temp. its more a case of degrees of cooling from  the outside temp , 30c outside 20c inside, 20c outside 10c inside , 17c outside 7c inside. etc

I can only assume your ac doesn't work properly if thats what you're getting inside. 

to date, I've had cool air from various cars inside the cabin, no matter what the outside temperature. however, I usually use it with recirculate air, ensuring max coolness. on many occasions, I've had to turn it off for short periods of time because it gets to cold inside the cabin, a common complaint from my wife. She herself has commented on it, a few occasions now she has mentioned that its not as cold as it used to be.

 

 

[983]

1 hour ago, Trewithy said:

With temp control set to cold, air distribution set to dashboard vents, and all the vents closed  except the one being measured I can get down to 7 degrees by varying the fan speed at tickover with the ac on. 

did you get that low with recirculated air?  I usually use that to get maximum coolness. 

[Trewithy]

10 minutes ago, 983 said:

did you get that low with recirculated air?  I usually use that to get maximum coolness. 

I rarely use recirc, may use it in heavy traffic so I am not breathing traffic fumes or when the car interior is very hot after being in the sun.

[iantt]

29 minutes ago, 983 said:

I can only assume your ac doesn't work properly if thats what you're getting inside. 

to date, I've had cool air from various cars inside the cabin, no matter what the outside temperature. however, I usually use it with recirculate air, ensuring max coolness. on many occasions, I've had to turn it off for short periods of time because it gets to cold inside the cabin, a common complaint from my wife. She herself has commented on it, a few occasions now she has mentioned that its not as cold as it used to be.

 

 

I'm sorry, ive only been a technician for 38yrs and certified to gas and diagnose Aircon by ford 

Ford must wrong then telling me that. Naughty ford.lol

[Luke4efc]

4 hours ago, iantt said:

I'm sorry, ive only been a technician for 38yrs and certified to gas and diagnose Aircon by ford 

Ford must wrong then telling me that. Naughty ford.lol

Just out of interest what sort of qualification does Ford put you through to do that? I'd assume you'd have to do city and guilds/SRAC, but to what category?

[iantt]

for the handlling/ gassing  its a health and safety course making you aware of the dangers / safe use, fines for miss use , characteristics of air con and principles of operation

all technicians have to have this certificate to operate aircon equipment.

diagnosis is fords own course c52.2 air conditioning elec control & diagnosis

[James Drebin]

On 6/8/2018 at 6:49 PM, iantt said:

I'm sorry, ive only been a technician for 38yrs and certified to gas and diagnose Aircon by ford 

Ford must wrong then telling me that. Naughty ford.lol

Awkward glances are exchanged. "Curb Your Enthusiasm" end theme plays out. 😄

 

[983]

On 6/8/2018 at 6:49 PM, iantt said:

I'm sorry, ive only been a technician for 38yrs and certified to gas and diagnose Aircon by ford 

Ford must wrong then telling me that. Naughty ford.lol

well, the funny thing is, you're wrong according to your original comment. because I've been monitoring the temperature from my vents, and I'm getting temps as low as 6.3, despite it being 25 outside temp. however, as stated, this fluctuates.

Having qualifications and/or experience doesn't mean you're always on the money. Ive had mine for nearly 20 years, and I still learn. 

 

 

[iantt]

My original post was only giving an indication of the temp difference. Not actual values. 

"The temp out the vent will be dependent upon the ambient temp. The system only removes heat, and its capacity to do so is finite, meaning that as the ambient temp rises so too does the vent outlet temp.

One thing it also does that makes it seem more efficient is that it removes moisture also. The dried cabin air doesn’t seem as hot, becuause it has better capacity to absorb moisture from your skin which is how your body dissipates heat " 

 

 

[983]

It's the ambient and inside temps that don't seem to be consistent. 

There has been a 6c swing in temperature from the vent, which makes a huge difference with the sun coming through the front windscreen, in almost identical temperatures.

Since originally posting, this has reduced in the amount of times I've had this issue, although not entirely.

Whats puzzled me, is all the parts seem to be in good working order, the only item I've had to change is the cabin filter, which in turn gave more force from the vents.