Dear Sheikh

I think you faced a trouble with aeration system  so all you need to check is :-

- you need 0.8 bar for air quantity between 1 - 2 m3 / min per m2 of aeration area

- Very hot air aeration 

- moisture

- irregular in extraction frequency 

Of course thats based on aeration homo silo ( like as Polysius octant system ) .

Regards

ILA

Mechanical & Process Engineer