1. Observe the operating instructions of the forced cooling fan in chapter "Operation and maintenance instructions for forced cooling fan /VE with part number group 1379..." (→ 2 222). 2. Before installing the forced cooling fan [1], check to see that the fan wheel and the fan motor are not damaged. 3. After installation, turn the fan wheel to make sure that the fan wheel does not rub in any place. The clearance between the fan wheel and fixed parts must be at least 1 mm.