I have been taught that my TEET should be 20 degrees In the attic in the return and the supply plenum. When I use my srh2 TEET might only be 16-17 degrees. When you take your Wet bulb do you do it at the return down stairs or in the return in the attic? I know because of how hot some of these attics are in Louisiana I might gain a degree or two in the heat of the day from downstairs to in the attic.
It should be taken in the return at the unit. The temp of the air in the space is not always the same as the unit. The performance of the unit should be judged based on the air it is conditioning not the air in the space. (although ideally they are the same) if you take both readings you can identify duct work issues
Cool. I've been wondering about that. Prior to getting the srh2 I never took a wet bulb. Now on a fixed orifice system I KNOW it's fine tuned..... Not just guessing what the superheated should be if there is no chart on the unit.