The most common causes of loss of suction are dirty filters or a clog in the hose. To troubleshoot, remove the hose from the vacuum, place your hand at the opening of the tank inlet and turn the vac on.If you feel suction at the inlet, the issue is with your hose or accessories. Check your hose and accessories for a clog. If no clogs are found, check the hose for a hole or crack - even a small crack can cause a loss of suction. If a crack or hole is found, replace the hose.