CLK W209 270 CDI A/C not working!

[JohnV270]

After i replaced the temperature sensor (the one under the radiator) and refilled with Freon the A/C worked and was blowing cold air but after ~1 hour or less of using the A/C, it started again to blow hot air through the vents. I also have the Stepper Motor Clicking Noise problem and haven’t solved it yet. But i think it's not because of the clicking noise, because my A/C wasn't working even before the clicking noise problem.
Interesting is the fact that sometimes when i turn on the AC and put it on LOW (digital clima control console) for 1-2 minutes it blows a little cold "breeze" just enough to make you think the problems is solved but then it blows again hot air.
What should i check next?
I diagnosed it with Star C4 6 months ago and that guys told me everything is ok...
Please help me.
Thank you.

 

[DSM10000]

You need to check the system pressure, if low then the compressor will not engage. Any garage should be able to test this for you or an A/C specialist. It sounds as if you have a leak somewhere.

 

[JohnV270]

Forgot to mention the fact that i did a presure test and everything is ok.
The problem is from elsewhere.

 

[JohnV270]

Problem solved. Presurse valve from compressor was burned.