Walk-in freezer problems

What to do with the frozen food

Signs of thawing to look for: weeping, staining, or damaged packaging. USDA's target for frozen storage is 0°F or below — at that temperature food stays safe indefinitely, and storage time only affects quality. Your health department has the final word on what you can sell.

Freezer not holding temperature

Start with the same checks as a cooler, in the same order: the set point and whether it's in defrost, both breakers, the door, product blocking the evaporator, ice on the coil, and the condenser. They are covered step by step in the walk-in cooler guide. Freezers defrost more often and for longer — Kolpak sets electric-defrost timers at the factory to four cycles a day of 45 minutes each, and Heatcraft gives two to four a day as typical for freezers — so a temporary rise in temperature is more common, and more normal, than on a cooler.

The rest of this guide covers the problems a cooler doesn't have.

Ice on the ceiling, fan guards or fan blades

Ice forming around the unit cooler — on the ceiling above it, on the fan guards and blades — is a defrost problem in the other direction: warm, wet air escaping from the coil during defrost and refreezing on cold surfaces. Heatcraft and Kolpak list the causes as:

• Defrost running too long after the coil is already clear.
• Too many defrosts a day.
• A failed defrost termination thermostat or timer, so defrost doesn't end when it should.
• The fan delay not working, so fans start while the coil is still warm and blow moisture into the box.

In normal operation, defrost ends when the coil reaches about 45–55°F, and a fail-safe stops it anyway if the termination control doesn't. Heatcraft's rule is to set the fail-safe at the defrost length plus 25% — a 20-minute defrost gets a 25-minute fail-safe. These settings are a technician's adjustment, but knowing they exist helps you describe the problem.

Coil still frosted after defrost

The opposite fault: the coil comes out of defrost still white. Heatcraft's list: the coil isn't getting above freezing during defrost, too few defrost cycles a day, cycles too short, or a failed timer or thermostat. On electric defrost, the first suspect is a burned-out defrost heater, which a technician tests for continuity. Left alone, the coil ices solid and the freezer warms up with everything sounding normal.

Door frozen to the frame, or condensation around the opening

The door frame of a walk-in has a heater wire running around the opening. Norlake and Master-Bilt's installation manual explains why: it stops condensation forming around the edge of the door opening, which in a freezer would otherwise freeze. Their manual says heater failure is usually suspected when condensation forms around the perimeter of the door opening. On a freezer, that condensation turns to ice, the gasket stops sealing, and the door can freeze to the frame.

• Don't chip or pry ice off the gasket — you will tear it.
• Check the heater is powered. It is usually on its own circuit or a switch near the door.
• Replacing the heater wire means disconnecting power to the walk-in first; it is often a technician or door-specialist job.

The same manual gives a target of 30–60% relative humidity around the walk-in, with a dew point of 50°F or less. A very humid kitchen will push condensation onto any door, heater or not.

Door hard to pull open just after closing

When the door opens, warm air rushes in. Once it is shut, that air cools and contracts, and the box pulls a partial vacuum — which is why a freezer door can be hard to open again straight away. Freezers have a pressure relief port, usually a small vent in the wall near the door, to let air back in. Kason, the company that makes most of them, explains in its patent that the port also releases pressure when the freezer warms up during defrost, and is heated so ice doesn't block it.

If the door is regularly hard to open, check the port: is it iced over, blocked by product, or not powered? Norlake and Master-Bilt connect it to a 115-volt supply. A dead heater lets it ice shut. That is a cheap part, and it is often what is behind a door closer that seems to be "too strong".

Frozen drain line, ice in the drain pan

A freezer's defrost water has to leave the box before it refreezes. Heatcraft's requirements:

• A drain line heater on freezer lines, running continuously, under at least 3/8 inch of pipe insulation — 20 watts per foot for a 0°F room, 30 watts per foot for −20°F.
• The heater has to cover the drain pan fitting too.
• The trap outside the refrigerated space, and a fall of at least 1/4 inch per foot.

Ice building up in the drain pan, or an icicle hanging from the unit cooler, usually means the drain heater has failed. Kolpak lists the drain line heater in its 6-monthly inspection. Once the line freezes, every defrost adds more ice, which eventually grows into the coil.

Ice on the floor

Norlake and Master-Bilt warn that leaving a walk-in door open for more than five minutes lets a film of ice or moisture form on the surfaces inside, and that standing water should never be left in a walk-in. Ice on a freezer floor is a slip hazard first and an inspection finding second. Common causes are doors propped open during deliveries, a sweep gasket that has worn away so air comes in under the door, and drips from a failing drain.

Federal rules require walk-in freezer floors to be insulated to at least R-28. A freezer floor that was never insulated — for example, a cooler converted into a freezer — is a much bigger problem than ice.

What this costs

86 Repairs reported an average vendor invoice of $1,000.42 for walk-in repairs, nearly twice the reach-in average. The freezer-specific failures above are mostly cheap parts — a heater wire, a pressure port, a drain line heater — but a failed drain or door heater left running for weeks turns into a solid-iced coil, which is not cheap.

What to tell the technician

• Make of the box and of the refrigeration system.
• Product and air temperatures, and when you noticed.
• Where the ice is: on the coil, around it on the ceiling and fans, in the drain pan, around the door, or on the floor.
• Whether the door is hard to open, and whether the frame sweats.
• Whether the inside fans and the outside unit are running.

Refrigerant work in the US needs an EPA Section 608 certified technician.

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