I have a 5 ton Bryant heat pump that just hasn't been it's old self lately. The compressor and TXV were replaced last fall. Seemed to do OK during winter, but this spring coil began freezing up in AC mode. Tech comes out and sees low suct pressure and immediately adds freon. Schrader valve is leaking too so he replaces core. Coil still freezes up, mainly at night. Comes back out and replaces TXV. Suction pressure is still low and coil still freezes. He is stumped now. I ask about airflow and sure enough turns out the insulation in the air handler is coming loose and needs to be secured. Air flows are now back in the 400 CFM/ton range. He says "let's let it run a couple of days and see how it works. You might have a cap tube plugged."
Being an engineer and tired of techs guessing, I've taken a few measurements. Based on these, what should I expect him to do or look for when he comes back out.
Outdoor amb 87F, WB 77F, Suct 65psi/48.5F (11.5 superheat), Disch 241psi/88F (27 subcooling), Indoor return air 72F, WB 60F, Supply 58.6F, WB 51F, liquid line temp @TXV inlet 89.6F, TXV outlet 89.3F, Evap disch line temp 58F. Liquid line sight glass clear and dry.
Equip documentation says target subcooling should be around 12F at these conditions. Refrigerant overcharge or something else?
Thanks in advance for your advice.