I have a 404A split system walkin with line setts approx 30 ft, I have a box temp of 12 deg F and dropping. System Pressures are 25 PSIG Low side and 175 PSIG High side. 12 inches from Compressor I get a 45 deg F. When adding 404A the low side pressures temp and PSIG drop raising my superheat. Currently my superheat is approx 55 deg F. After de-Iceing evap coil and TXV and Selnoid valve I noticed TXV is frosting up imediately. I changed the selnoid coil and no change.
My thoughts are recovery refridgerant and change both TXV and selniod valve. Approximately 6 months ago the coil went bad on the valve... Any suggestions or thoughts???