A vacuum cleaner comprising a dirty air intake and a cyclonic separating apparatus connected in series. The cyclonic separating apparatus comprises a plurality of cyclonic separators connected in parallel. The vacuum cleaner further comprises a bleed valve provided upstream of the plurality of cyclonic separators. The bleed valve opens to admit bled air into the plurality of cyclonic separators in response to a drop in pressure in the vacuum cleaner. The bleed valve is also connected to the inlets of the plurality of cyclonic separators via a common plenum.