1. First, check if the collection tank is full. If it is, emptying it should restore suction.
2. If the tank isn’t full, check the filter. If the filter is dirty, remove it from the collection tank and clean or replace as needed. To replace it, click here: http://www.bissell.com/filter-2036705?productid=2949
3. Make sure the float isn’t activating prematurely. If it is, you’ll need to order a new tank. You can do so by clicking here: http://www.bissell.com/collection-tank-2038371?productid=2949
4. See if the floor nozzle is on tightly and snapped into place.
5. If you still don’t have good suction, please take your cleaner to a technician. You can find your nearest BISSELL® Authorized Service Center by clicking http://www.bissell.com/support/product-support/service-centers or by calling 1-800-237-7691, available 24 hours a day.