Overfreezing and icing in fridge or freezer
One cause of icing up and over freezing in a fridge or freezer can be a poorly fitting or damaged door seal. If the door seal becomes distorted the seal will start to allow warm moist air into the freezer or fridge. This will cause snowy ice to deposit around the point of entry which will eventually cause the compartment to completely ice up.
If the door seal is worn, then clearly it needs replacing but sometimes it’s just a matter of re-shaping the door seal with the aid of either a hair dryer or a warm cloth. Carefully heat the seal and try to form it back into the right shape closing the door and letting the seal cool before opening the door again.
Another possible cause of frost in fridge or freezer
If the fridge or freezer is not level, the cabinet may become twisted, this causes the door to not fit properly and the seal to not seal properly. This can allow gaps which again allows warm moist air to be drawn into the appliance. If affected make sure the appliance is properly level by adjusting the feet or if necessary by placing some packaging under the feet. You can always try the paper test, which is to place a piece of paper between the seal and the frame and see if it will hold, if it doesn’t the seal will be letting warm air into the unit.
Note: Many modern fridges and freezers do not have replaceable door seals. Only complete new doors. This is disgraceful but just another symptom of manufacturers making appliances less repairable in the race to make finished goods cheaper.
On the subject of door seals it is not advisable to open any fridge or freezer door by curling your finger’s around the frame as this can result in the seal splitting. Always use the handle, and don’t forget if you do reshape a door seal always fully defrost the unit afterwards. Another point to remember is that if the door seal has split on the face that touches the frame it needs to be changed. If it is split on the outer side crease it is only cosmetically unsightly.