I am A new tech and after charging a system the way I was taught in school. I went and checked the tempature at the supply and at the return and I was looking for a 20 degree differential. However, it was only 12. Supply 71 and Return 83. After researching this forum I found that if it is above 20 it is an indication there is poor or low air flow. Dose anyone have experience as to what would cause the the differential to be below the 15-20,
that I should be getting. Thanks in advance.