By Commercial Service Company · August 9, 2026
A little frost on a commercial freezer is normal. Sheets of ice on the coil, a door that won't seal, or a floor that's slowly icing over are not. When frost keeps coming back after you clear it, the freezer is telling you something is wrong. Below are the most common causes we see on refrigeration units across central Arkansas, and how to tell a quick fix from a service call.
One rule first: never chip, scrape, or pry ice off the evaporator coil or its fins. The coil holds refrigerant lines, and a screwdriver or ice pick can puncture one. That turns a frost problem into a refrigerant leak and a much bigger repair. If a coil is buried in ice, shut the unit down, let it thaw, and get a technician on the phone.
The Defrost System Isn't Doing Its Job
Most commercial freezers run an automatic defrost cycle on a schedule to melt the light frost that builds on the evaporator coil. When that cycle fails, frost never gets cleared and it snowballs into a solid block of ice over the coil. Airflow drops, the box warms up, and the unit runs almost constantly trying to keep up.
Defrost problems usually trace back to a failed defrost timer or control board, a burned-out defrost heater, or a bad termination sensor. These are electrical components tied directly to how the refrigeration system runs, so diagnosing and replacing them is a job for a licensed technician. If your coil keeps icing over even though the door seals well, a defrost failure is one of the first things a tech will check.
Worn or Dirty Door Seals
Door gaskets are one of the most common and most overlooked causes of frost. When the rubber gasket cracks, hardens, or tears, warm room air leaks in around the door. That warm, moist air hits cold surfaces and freezes, which is why you'll often see frost heaviest right around the door frame.
- Look for gaps, tears, or flat spots in the gasket.
- Try the dollar-bill test: close the door on a bill and pull. If it slides out with no resistance, the seal is weak there.
- Wipe gaskets clean regularly so food debris and grease don't hold them open.
A worn gasket is often a straightforward replacement, and it's one of the cheaper fixes that can make a real difference in frost and energy use.
Humid Air Getting Into the Box
Every time the door opens, humid Arkansas air rolls into the freezer, and that moisture has to go somewhere. In a busy kitchen or grocery cooler, a door that's propped open, opened too often, or left ajar will frost a box up fast. Overloading the unit or blocking the internal fans makes it worse by hurting airflow.
- Keep doors closed and don't prop them during service.
- Make sure auto-close hinges and door closers actually pull the door shut.
- Check that strip curtains, if your unit has them, are intact and hanging correctly.
- Don't pack product against the fans or air vents inside the box.
These are habits and small fixes your team can handle in-house, and they often solve a frost problem without any parts at all.
Drain Line Problems
When the defrost cycle melts frost, that water is supposed to flow out through a drain line. If the drain clogs with debris or freezes up, water backs up, pools, and refreezes, sometimes as ice on the freezer floor or under the coil. A frozen or blocked drain can also send water where it doesn't belong and lead to a re-freezing loop that never really clears.
Keeping the drain pan and drain line clean is reasonable routine maintenance. But if the line keeps freezing, backing up, or you can't find where the water is coming from, that points to a deeper issue with defrost timing, drain heaters, or how the unit is running, and it's worth having a technician look at it.
When to Stop and Call
Clear ice from the door, keep gaskets clean, keep drains clear, and train your team on the door, and you'll head off a lot of frost problems. But if the coil keeps icing over, the box won't hold temperature, or you're seeing repeated frost after you've fixed the easy stuff, don't keep clearing ice and hoping. Anything involving the defrost electronics, refrigerant, heaters, or compressor needs a licensed refrigeration technician, both for safety and to protect your equipment.
Commercial Service Company has kept central Arkansas businesses running since 1976. If your freezer keeps frosting over and you want it diagnosed and fixed right, call us at 501-548-2374 and we'll get a technician out to take care of it.