Detecting AC problems

Have you ever seen one frost blanketing the air conditioning as well as in this picture? it is the discharge line servicevalve, generally located on the right side of the outdoor unit. if you've seen or experienced middle instead of your air conditioner should be checked on your subscription technician, signs like this a lot cause but this is just one example that happened to occur on the unit is still new, so if you happen to experience the 
better at preventing it from becoming more severe damage. 
Complaints such as experienced by a colleague on my new purchase and install this air conditioner a few months ago, he complained his conditioning this feels less cold even used since the first time you hear a "tek..tek..tek" with a span of 1 to 5 seconds coupled droplets of water from the cold air blowing holes in his indoor. the owner said that at the time of the installation leak at the connection but no charging is done by the technician in question. 
After checking through the pressure gauge (manifold) turns his freon pressure is below normal at 28 psi when it should be if the room temperature has not reached the ideal temperature measured pressure can be more than 60 psi and the pressure will drop as the temperature in the room is reached, the cool down the room temperature, the more its freon pressure.