The Zanussi ZRT 6556 Refrigerator has some known problems that occur often. Here are some easy to do solutions for the problems or error codes your Zanussi might be giving you.
The appliance is not receiving power due to a possible power cut or a blown fuse.
The freezer or refrigerator section is warmer than the set temperature, which may affect the storage life of food.
The freezer or refrigerator section is colder than expected, which may lead to food freezing inappropriately.
There is a significant build-up of frost and ice, which can reduce the efficiency of the appliance.
The appliance is making more noise than usual, which could indicate an issue with the internal components or installation.