Low suction pressure / high superheat

Refrigerant

AirCompDX - Field Reference for Air Compressor Techs
All HVAC symptoms
1

Undercharge / leak

high
CheckBoth superheat high and subcool low.
FixLeak search, repair, evacuate, weigh in charge.
2

Restricted TXV or drier

high
CheckFrost after restriction; large temp drop across drier.
FixReplace drier and TXV; recover and recharge.
3

Low load / low return air temp

info
CheckReturn-air dry bulb below 70°F.
FixNormal — do not chase charge; retest at design conditions.
Safety

Pull the disconnect and lock out before opening HVAC equipment. Discharge dual-run capacitors before handling. Refrigerant recovery and brazing require EPA 608 certification and proper PPE.