--- title: "Frost is building up" description: "JennAir frost is building up — a sheet on the back wall, ice on the floor of the cabinet, or frost that returns within days of being cleared." url: "https://jennairmiami.support/symptoms/freezer-frost-build-up/" date_modified: "2026-08-24" Appliance type: "Freezers, Refrigerators" --- # JennAir frost is building up ### The fastest diagnosis is the code Check the door first — the banknote test all the way round, and whether anything on a shelf is holding it a fraction open. A door that does not seal lets in humid air continuously, and in this city that alone can outpace a perfectly good defrost cycle. Then look at whether the frost is a haze or a sheet: the second one is a repair. ### Frost is the message, not the problem A frost-free cabinet makes ice on its evaporator all the time and melts it off on a cycle. When the frost starts winning, one of four things is happening: the heater has stopped, the sensor is not calling for the cycle, the control is not running it, or the drain has iced closed so the melt has nowhere to go. All four look identical from the kitchen and all four are measured rather than assumed. ### The fifth cause, which is free A door. Every second a seal is not flat, humid air is being drawn into a cold cabinet, and its water stays behind. In this climate a seal that is merely tired — not failed, tired — can outpace a perfectly healthy defrost cycle between June and October. The banknote test takes two minutes and it is the first thing to do. The defrost heater What melts the coil clear each cycle. When it goes, ice accumulates until air cannot pass. The defrost sensor or control The cycle never runs, or runs too briefly. Same symptom, different part, and both are measured rather than guessed. A drain that has iced closed The cycle runs, the ice melts, and the water has nowhere to go — so it refreezes on the floor of the cabinet or lands on your floor. A door letting humid air in Seal, alignment, or a paneled door whose hardware has loosened. The cheapest cause and a very common one here. Summer, on a cabinet that was marginal Nothing has broken. Something has been borderline for a while and August found it. Haze or sheet? A light haze on packaging is normal. A sheet on the back wall is not, and neither is ice on the cabinet floor. The banknote test on the door Several points, all the way round, including the hinge side. Look for anything holding the door A drawer not pushed home, a package on a shelf edge, a bin out of position. Look for water underneath Water on the floor means the drain rather than the heater, and that is the smaller repair of the two. Do not just defrost it and hope Clearing the ice removes the symptom and leaves the cause, so it comes back — usually sooner. Do it if you need the cabinet this week, not instead of the repair. And it will not settle on its own What it usually means A sheet of ice on the back wall Frost that comes straight back after clearing Water underneath the cabinet The fastest diagnosis is the code Check the door first — the banknote test all the way round, and whether anything on a shelf is holding it a fraction open. A door that does not seal lets in humid air continuously, and in this city that alone can outpace a perfectly good defrost cycle. Then look at whether the frost is a haze or a sheet: the second one is a repair. Frost is the message, not the problem A frost-free cabinet makes ice on its evaporator all the time and melts it off on a cycle. When the frost starts winning, one of four things is happening: the heater has stopped, the sensor is not calling for the cycle, the control is not running it, or the drain has iced closed so the melt has nowhere to go. All four look identical from the kitchen and all four are measured rather than assumed. The fifth cause, which is free A door. Every second a seal is not flat, humid air is being drawn into a cold cabinet, and its water stays behind. In this climate a seal that is merely tired — not failed, tired — can outpace a perfectly healthy defrost cycle between June and October. The banknote test takes two minutes and it is the first thing to do. ### It was fine all winter and started in June. The most South Florida sentence on this site, and genuinely diagnostic. Every door opening in August brings in air carrying several times as much water as in February. A cabinet with a drain partly closed or a door sitting a fraction proud copes in winter and stops coping in summer without anything having actually broken. Both of those are cheap. ### Can I defrost it myself? You can, and it works for a while — which is the trap. Manual defrosting removes the ice and leaves whatever stopped the cycle, so it returns. It is worth doing if you need the cabinet working this week. It is not worth doing instead of finding out why. ### There is ice on the floor of the freezer. That is the drain rather than the heater: the defrost cycle is running, the ice is melting, and the water cannot leave. It is a smaller repair than a heater and it is worth doing before it reaches your cabinetry. --- **[Read full article: Frost is building up](https://jennairmiami.support/symptoms/freezer-frost-build-up/)**