We have been delighted with our vacuum cleaner over a number of years, but recently it has become heavy to push and can't seem to sense whether it is on carpet of hard floor, suggesting that the Active Height Adjustment System is not functioning correctly.

We have changed the filters, bag and sensor strip but this hasn't made a difference - please can you advise whether there is anything else we can do?

Stephen Paul, August 2008

If the X is difficult to push then it could be a couple of things; check that the roller brush is actually moving - if it isn't then the drive belt may have snapped - our 14 year old X1 only needed one new drive belt last year and the toothed one can be picked up off ebay or from Sebo. Also check that the sensor wheel isn't blocked with any dirt in between the wheel and the floor whilst the rear wheels could also be blocked with dust.

Ryan S, September 2008