About 4 months ago, I recommissioned an older dormant system. It is a large walk-in freezer, set and holding at zero degrees. I stopped by today to check out it's operation. Noticed accumulator and exposed suction lines frozen over up to the suction service valve on the compressor. I know icing/frosting is common on exposed low pressure pipes and components.
After inspecting the inside evaporative coils, I found the TXV output, distributor, and cap tubes iced and frozen solid. SH is right at design specifications of 9* (at evap) with a 10*TD.
Coil is clean as a whistle and defrosting perfectly, just curious why that little section is iced solid.
What causes the icing of the TXV's distributor end and cap tubing?
Is it due to the fact that they are not in direct contact with the electric defrost elements?