Mobile Air con repair ****...

[steveo3002]

The problem with using compressed air for leak finding is that the filter-drier will become saturated with moisture, sometimes to the point of becoming blocked. Fortunately, most filter-driers are included with a replacement condenser, which is usually the cause anyway.

would it not be saturated if the car was driven around for a year or two with a broken condenser anyway?

 

[Ubique]

Possibly, but it would have greater problems with aluminium oxidisation, corrosion and moisture causing rust in the compressor. I think that the moisture content of compressed air as it expands into the AC system would form more droplets than would condense from 'free air' assuming the hole(s) in the AC system were sufficiently large for water molecules to get in anyway.
If you absolutely had to use compressed air, then a condensing drier or at least an inline separator would remove most of the moisture before use.

 

[jimbo84]

Most cars designed and built since the early 90's operate on the 'reheat' principle - that is, all incoming air is chilled and therefore has some if not most of the moisture removed, it is then diverted through the heater matrix to a greater or lesser extent dependent upon the target temperature and the current internal temperature. It might seem 'wasteful' but the heat costs nothing as it's a by-product of combustion and once the evaporator temperature is <5deg. C the compressor will be cycling on & off (or the proportioning valve will be reducing the load). The benefits are less condensation in winter (providing the glass is cleaned of contaminants so there is nothing for the water to be absorbed by) better heat regulation and cleaner cabin air. Most 'smelly' heater vents are due to the aircon being ineffective or being turned off, allowing bacteria to fester in the vent ducts, dry, cold air doesn't transmit bacteria very well, most of it is caught up in the condensate and carried out of the vehicle through the condensate drain.
Seals don't really dry out as such, they will eventually age to the point of leaking but by then, the condenser is likely to have leaked at least once.

The problem with using compressed air for leak finding is that the filter-drier will become saturated with moisture, sometimes to the point of becoming blocked. Fortunately, most filter-driers are included with a replacement condenser, which is usually the cause anyway.

That probably explains why the aircon button seems to do nothing in the better half’s car, the AC seems to just be on all the time regardless of if the button is pressed or not.

 

[Ubique]

It probably is, on vehicles with a proportioning valve or PWM controlled clutch, the AC switch just limits the maximum duty cycle to 10-15%

 

[Smallfry]

The only car I have had where the aircon worked anything like properly was an early XJ6. It had a huge compressor, and was filled with Freon 12. There was no bottom limit on it, and you could make your teeth chatter, and see your breaths.