Arrived at location on 1/24/22 - found walk in box at 15 degrees. Evaporator coil was iced up on both sides and both fans were running. Removed all ice and went to condensor unit. Condensing unit did not have a disconnect at unit so the breaker had to be located and shut off to kill power to the fans. Checked pressures and they were good for 404A. Unit is designed for 10-12 degrees of superheat and I had 12 degrees at a box temp of 5 degrees. The door leading into the walk in was not shutting properly. When closed it would leave about 1” gap. This can cause ice to build up on the coil. I adjusted the door so it would close properly. I also found a very pitted contactor at the condensing unit. Replaced with one from truck stock. Tested defrost and all was okay except the the grasslin timer wheel was very stiff when turning to set correct time. This also could cause ice to build up if the clock was to get stuck and not go into defrost. I did not have a grasslin but replaced with a pa