Estate freezer frost buildup

Some frost is normal in a manual-defrost chest or upright freezer and has to be removed by defrosting it a few times a year. Rapid or heavy frost means humid air is getting in through the lid or door seal, or, on a frost-free model, that the automatic defrost system has stopped working.

Quick checks first

• Check whether your freezer is manual defrost or frost-free; the owner's manual tells you and explains how to defrost a manual model.
• Check that the lid or door closes fully and the gasket touches the cabinet all the way around.
• Look for packages or baskets that stop the lid or door from closing.
• On an upright, make sure the cabinet is level or tilted slightly back so the door swings closed.

Manual defrost is normal Owner check

Chest freezers and many basic uprights do not defrost themselves. Frost slowly builds on the walls or shelves and must be removed when it gets about a quarter inch thick, following the owner's manual. Thick frost reduces storage space and efficiency but does not mean a part has failed. Use the manual's method; chipping with sharp tools can puncture the cooling tubes in the walls.

Lid or door seal Owner check

Frost that builds fast, especially near the top of a chest freezer or along one edge of an upright door, means room air is leaking in. Torn or flattened gaskets, a bent lid or hinge, or something caught in the seal are the causes to look for. Clean the gasket and the surface it seals against, and close the lid on a strip of paper at several points to see whether it grips.

Door use and humidity Owner check

Every opening lets moist air in. Long or frequent openings, warm food placed inside, and humid weather all increase frost. Las Vegas air is dry most of the year, so heavy frost here points to a seal problem more than to humidity, though monsoon weeks can add a little.

Frost-free defrost failure Technician

On a frost-free upright, frost covering the inner back panel, the vents or the fan means the defrost cycle is not working. The heater, the defrost thermostat or the timer or control can be responsible. If left alone, the coil ices over and the freezer stops holding temperature. A technician confirms which part of the circuit failed.

Blocked defrost drain Technician

Melt water from a frost-free defrost runs down a drain. If the drain freezes or clogs, water refreezes at the bottom of the cabinet and builds into ice. A technician clears the drain and checks why it froze. A drain that freezes repeatedly can point to a defrost heater that is not warming the bottom of the coil, or to a drain heater on models that use one.

Repair cost

Typical total ranges for the Las Vegas area, parts and labor included. The final cost depends on diagnosis, the exact model, parts availability and whether other damage is found.

When to call for diagnosis

Call for service if a frost-free freezer develops frost on its back panel or vents, or if frost returns within days after a full defrost even with a good seal.