I run a small grocery store which has an indoor walk-in cooler built by HEATCRAFT. The complete refrigeration unit is located on the top of the cooler room. As the weather is getting hotter and humid (storms almost every day) and the store does not has A/C. Lately, I discover the evaportor coil get frozen up (since the store has no A/C) frequently, and the cooling is not quite as efficient as in later summer. It was able to go down to 34F with no problem. Lately, it seems that the compressor is continuouly running, but the cooler temperature stays at 38-40F (even when the coil is not covered by ice) and I suspect that the liquid refrigerant (R12) is circulating the condensor coil but not going down to the evaporator coil inside the cooler room. I remember 2 years ago my refrigeration technican told me due to the hot (in the summer) and cold (in the winter)temperautres, the cutin and cutout pressure settings on the Penn diff. pressure need to be adjusted.
Anyone has any info regarding to the pressure setting versus the surrounding temperature? The compressor is made Copeland and the refrigerant is R12. Thanks.