Hose doesn’t have suction

\015 My DC18 has suction when it is unlatched like to do floors with the roller attachment. However when I lock it upright to use the hose it loses suction totally. I have cleaned the filter as well as removed the hose for obstructions. When latched upright it makes a totally different noise than when unlatched. After a few seconds in the upright position it makes a noise that I can only describe as if you were to put your hand over the hose when it was working properly.\015 – Dyson DC18 all floors Bagless Upright Cyclonic Vacuum