I received much the same advice from my auto tech buddies. The A/C system needs to be used regularly to keep the o-rings from shrinking and then leaking.

In the midwest where I lived for a few years the A/C got used almost all the time. There were 2 weeks in the spring and two weeks in the fall when one could get by -- comfortably -- with no A/C but all other times one needed the A/C to address the heat and humidity or the cold and humidity.

Here in northern CA where I live I can go some time between having to use the A/C but I remind myself to use the A/C at least once a week for 15 or more minutes. I also remind myself that before I park the car for the night I drive with the A/C compressor off but the vent fan still on to dry the A/C system to avoid the development of mold/mildew.

I have to add the auto climate A/C system in my Boxster is one fine heating/AC system. Set to 72F the thing gets the cabin to that temperature in practically no time and keeps it there in 100F+ heat or sub freezing cold. And icing on the cake is I can't tell the thing is running from the way the engine feels. The variable displacement compressor is a work of art.

The Turbo's auto climate control heating/AC system is likewise a fine system. In 118F heat with the auto climate temperature control set to 72F the A/C system was not struggling at all. The fan speed showed just a few bars which is not even a mild breeze in the cabin. Had I not had the benefit of the outside temp display on the dash I would not have known how hot it was outside the car. well, at least until I stopped to fuel the car. Then, oh my, it was like entering into the fires of Hell.

Likewise last Dec. back in the midwest in the low single digit cold the heater worked just fine. 'course the A/C system was sans the compressor as it is not engaged when the outside air temperature is below IIRC 34F (to avoid ice build up on the evaporator). But even so the auto climate feature still works just fine and the cabin was comfortable that I drove in light summer slacks and a short sleeved shirt. 'course, when it came time to get out of the car to fuel the car I had to don my heavy winter coat, wool cap, and heavy ski gloves to avoid freezing in the cold. Jesus it was cold!

 

I too have the same experience as our macster, the 997.2 ac system is a good one. I live in a tropical country where the temperatures are always in the 29 to 34 c range, ac can keep inside cool even at 4 to 5 bars on the speed range. Ac is almost always on when the car runs, except wheni go up the mountains where the temps drop.
With cab's experience, it verifies the fact that low refrigerant will kill the compressor due to oil starvation. I guess the main purpose of our thread, whether my system has a leak or is just normally bleeding some refrigerant, is let's be aware of our ac. Macs advise of cleaning the condensers is a good one, I placed rad grills when the car was new. Ac repair is not cheap. I just asked the dealer what they recommended and the bill was $900. I can only imagine how much it would be to replaced the compressor.
I'm keeping my fingers crossed that the system does not loose the 200g I put in quickly.

 

Update on ac condition. After putting in 200 g car got colder. However I felt it was still not as cold as before. I then decided to use a recovery machine evac and refill with 900 g of refrigerant. Ac is back colder than before, and the hissing on start up is now gone. Machine checked for leaks. No abnormal leaks monitored. Another learning incident for me.

 

OOC, what is a machine check? The best way to find leak is with dye IIRC.

Thanks

 

the Denso recovery machine pulls the neccesary vacuum on the system. After which it conducts a leak test. Everything is automated and computer controlled.. My guess is it monitors whether the vacuum drops after a certain period of time. If the system passes the leak test it then proceeds to charge the system with r134a. All of this is happening with the engine off. It then tells the user the process of charging has completed and system has passed all tests.