CH&A unit is turned on, blower is working, but fan doesn't turn on automatically, l can push the fan blade and it starts working.. what's the problem.

CH&A unit is turned on, blower is working, but fan doesn't turn on automatically, l can push the fan blade and it starts working.. what's the problem.
Sounds like your fan needs some lubrication or the bearings have gone bad. I have seen this happen with several stand alone floor fans. Dirt gets into the bearing area increasing resistance. It requires more force to start a fan than it takes it to keep moving. That is why you can get it going if you start it turning by hand. It may just be time to replace the fan.

Your fan motor has starter windings that initiate the starting of the spin, this draws about double the running amps. Once the motor spins it drops down to a more efficient running winding. In other words you probably need a new motor.

Could also be a bad capacitor depending on the design of the motor.