05-17-2008, 11:17 AM
I need some help with trying to figure out superheat a R-22 unit. I take a superheat reading and I get 21F on the first reading and then 15 min later I take another reading and I get 4F superheat. 15min later, I take another superheat reading and I get 15F. I have a fieldpiece duel themometer with the fieldpiece pipe clamp and the wetbulb sock thermocouplel with a new low side R-22 gauge. I have calibrated both sides of the thermometer with ice water acording to the directions and reading this forum so the thermometer is working correct. I am taking the pressure reading and the pipe temp reading at the suction line on the outside condenser and the wetbulb sock temperature is in the return air flow before the evaporator. I am not charging this unit, I am just checking the superheat and trying to get a feel if the unit is over charged or undercharged. Is the suction line supposed to sweat? yesterday I noticed that the suction line outside where I take the temp/pressure readings was sweating. Should that pipe sweat? Why am I getting different readings everytime I take a superheat check? The only temp reading that changes is the pipe clamp reading outside on the suction line. Please give me some advice?