A full 99% of the parts sent back to manufacturers' are not defective.
Compressors, reversing valves, and other parts are diagnosed as failing when the real issue was improper diagnostic techniques.
Regularly scheduled and preventative maintenance is the key.
A frozen lineset or a frozen coil is a good indication of a dirty filter or filter that is too restrictive. Some of the higher priced pleated or layered filters can actually resrict the airflow to the point of causing problems such as those in the pictures.
It's a whole different ballgame out there.
With the advent of R410A and the alternative refrigerants for R22 such as MO99 and r421A you really have to know your stuff.
Your responsibility as a maintenance technician is to assure the ensure the proper regularly scheduled and preventative maintenance is performed.
The type of filter is important also.
Did you know that some filters cause more harm than good.
When do you change filter?
You will see filters advertised as good for 90,
180 days etc. Wrong!
When do you change a filter?
When it's dirty!