have just finished school and am arising questions not answered by insructers.Dealing with it in the field.Copper thieves are giving a boost in our economy and we are changing out yet another unit destroyed.I am running into a similar problem with a unit as was presented by comfortable air's.It is a carrier split and I don't have the old numbers as it was yanked by construction crew but have new ones check it out and help me figure it out.I went by manufactures start up proceduces and am drawing a blank on my SH and SC measurements
Carrier 38ARZ012-501 SP 46# sat. temp 20-45 line temp 25 degeree SH 14 degrees subcooling OSA temp 80 space temp.74 delta t. across coil 25.
charged per manufacters directions and is TXV so was by there charging curve on the unit at 180# pressure on liquid with 80 line temp. met the curve and subcooling looks with in reason but what happened to superheat.Unit should be feezing up with this temp. but in normal operation all day today with a good sweat to the compressor. No matter about the addition of freon suction stayed the same. We are installing many of these units all over roof and temps are all over the place. So super heat and subcooling are relavent but where do you draw the line and what is up with installing these new units with 10 year plus air handlers and txv's.