today i was working on a trane packaged 5 ton a/c only roof top (R-22) and once i had the unit running with my gauges on my suction pressure was reading 90 psig and my head was about normal 220 psig (71 degree day) my sub cooling was low and my superheat was high i calculated a 13 degree diff. across my liquid line drier. so i recovered the refrigerant, brazed out the old drier and brazed in a new one pressures and temps were looking normal. what i dont understand is why did my head pressure remain the same. i am learning every day so any suggestions that would help me understand this situtaion.