Tech found system very low on R410a refrigerant. Tech also found 40/5uf dual capacitor reading very low at 33.8uf. Heat strip sequencer was documented to be stuck closed last time we were here. We replaced evaporator coil in 2023 and compressor in 2021. Reversing valve looks like it has been replaced before as well. Inspected system. Found oily residue on and around suction line king valve. Used ultrasonic detector to confirm king valve is leaking. Swept the other field brazed joints and found none of them leaking. Used soap bubbles and confirmed king valve leaking out of the top threaded cap. Tech tightened cap as tight as possible and soaped again. Did not find any more soap bubbles. Tech found 10uf blower capacitor reading weak at 8.2uf. Tested heat strip sequencer due to recent history of it sticking. It stuck closed on the first call for heat strip. Tapped on sequencer and it opened. Tech unplugged 5kw heat strip until sequencer is replaced. Tech leak searched recently repl