How long must a refrigerator be left upright after being leaned at an angle before operation

The short answer is to check with the manufacturer. That way you can be sure to stay within warranty guidelines.

The longer answer is that it varies from model to model. When a refrigerator is placed in a non-standard position (for example on its side), compressor oil can run out of the compressor and up refrigerant lines. So if you don't stand it upright and wait, the compressor will pump without sufficient oil -- not good.

-M

Clean empty refrigerators should be stored upright and kept dry. You should prevent moisture building up inside the stored refrigerator - perhaps by removing the door or by keeping the door open.

The manufacturer's instruction booklet may have a section on storage.

Unused refrigerators are a potentially fatal hazard for children, who may get trapped inside. For this reason doors should be removed, locked closed or prevented from being closed (using a child-proof mechanism).