If the air is getting hot quickly then it would indicate a blockage. If the sound is a high pitch whine then you have blockage. The only way i see to find the problem is to disconnect the hose and look through it. Dig in to any passages to make sure they are clean. I use a small flashlight when looking for clogged passages. shine the light in one and and see if it is seen out the other end. Usually you get some kind of light. if not then your clogged up.
If this is a bag less unit, you may need to clean the washable filter or change the internal filter
Vishant, January 2008
