Lack of suction

I appear to have suction but, when vacuuming there is not enough suction to pick up all the dirt. I have checked all the trouble shooting tips below and the problem is persisting. There also seems to be some overheating and "blowing" from the where where the coil is located.I assume you have confirmed that the hose is not partially blocked at all. With it removed from the machine, try running a small round stone from one end to another to see if it is totally clear.Secondly, the filter on top of the machine (the one you see when you empty it), this needs to be cleaned/washed on a regular basis - follow the instructions on the filter.Thirdly, does the lack of suction apply to all the attachments? If it is the carpet attachment, this does become clogged up with hair etc winding itself round the brush and the internal drive unit in the head, thus slowing it down. Also dirt and dust cloggs it up inside the head as well. It is posible to take the head to bits to clean it. Thanks