“The biggest driver of fridge breakdowns is the condenser coil, where the gas gets condensed and forms refrigerant,” Palmer-Spring explained. It’s a metal grid that, depending on the model, sits at the back of the unit, underneath it or, on some high-end refrigerators, up top. Because it’s tucked out of sight, it collects dust, grease and pet hair, and that buildup keeps it from doing its job.
Article source: https://www.huffingtonpost.co.uk/entry/fridge-mistakes_uk_6a74a288e4b04fcbf74d8573