These are short answers. Each one links to a longer guide when a fuller explanation helps.
Getting help
What should I have ready before I ask for help?
The temperature the box reads, whether the evaporator fans and the outdoor unit are running, any ice you can see, and when it started. If you know the brand or a model number on the condensing unit, add that too. The request page has a full list.
Is a warm walk-in always an emergency?
If it holds food, treat it as urgent, because time above 41 degrees counts. A slow drift of a few degrees over a week is less urgent than a box that is climbing now, but it usually gets worse in Mississippi summer heat.
Can I fix a walk-in myself?
You can check the door, the controller setting, the coil for ice, and whether the outdoor unit is on. Anything involving refrigerant, electrical panels or capacitors should be left to a qualified technician, both for safety and because refrigerant handling is regulated.
Warm boxes and ice
How do I tell a compressor problem from a fan problem?
Fans move air inside the box. The compressor and condenser fans sit in the outdoor unit. Inside fans running with a silent outdoor unit points to the compressor side or its power. An outdoor unit running with dead inside fans points to the evaporator fans. The not cooling guide walks through it.
What is a defrost cycle?
A short, scheduled pause in cooling that melts frost off the evaporator coil, usually with electric heaters. A clock or controller starts it. When it fails, frost builds into solid ice. See freezing up and defrost repair.
Why is there ice on the floor but not on the coil?
Melted frost is leaving through a blocked or frozen drain, or the door seal is letting in damp air that freezes near the entrance. Follow the ice back to its source rather than chipping it away.
Why does turning the thermostat colder not help?
A colder setting asks the system to run longer, and a coil that is already iced cannot cool no matter what the setting says. Fix the cause of the ice first. On some controllers a lower number means colder, so read the display carefully.
Noises, power and breakers
The compressor hums but does not start. What does that mean?
It often means a start or run capacitor has weakened, a contactor is worn, or the compressor itself is struggling. Do not keep cycling the power. Turn it off and get it looked at, because repeated start attempts heat the compressor.
Why does the breaker keep tripping?
Causes include a failing fan motor, a heater that has shorted, a compressor drawing too much current, or damaged wiring. A breaker that trips is protecting something, so resetting it repeatedly is not a fix.
What should I do after a power outage?
Keep the door closed during the outage, note the time, and check food temperatures before you restart anything. When power returns, watch the unit start and listen for anything unusual. The storm recovery guide has the details.
Upkeep and this site
How often should the coils be cleaned?
Condenser coils near cooking equipment or dusty areas need attention more often than a clean back room. In Hattiesburg summers a dirty condenser is one of the first things to trip a compressor on overload. The maintenance checklist suggests a routine.
Where does the information I send go?
It is saved on this site and sent by email to the site owner so a technician can follow up. It is not sold. The privacy policy explains what is collected and how to ask for removal.