freezer temperature dial

whitesatin

We have just had to defrost our frost free upright, Zanussi, freezer as the alarm kept coming on and the fan was working overtime, and very noisy. It is kept in a room which is part of a divided garage, attached to the house. Both divisions of the garage tend to get pretty hot in this weather as there are glass doors and windows. The front part gets hottest in the morning, the rear part in the evening. Both are ridiculously hot all day just now. Anyway, I've cleaned it and started it going again and all seems fine this evening. To prevent a repeat of this issue, I'm closing curtains and blinds but I'm wondering whether I should adjust the temperature dial (set at 3 by the installer) and if so, should I got up to 4 or 5, or even down to 2? The numbers are 0-5, with 0 being off.

I'd be grateful for any advice as I can't get a definitive answer from the manual which just says that whilst an intermediate setting is usually the most suitable, the exact setting should be chosen bearing in mind that the temperature inside the freezer will depend on room temperature, frequency of door opening, location etc.

I want to buy some food to put into it tomorrow so would like to know how to keep it and the freezer in optimum condition.

Thank you.