N211M Models feature stainless steel, 303 grade shafts and bronze pump construction which helps ensure corrosion resistance. Ball bearings and mechanical seals are found on upper tier models while others employ bronze or carbon bearings and lip type seals. Optional nitrile impellers are available while neoprene rubber is standard. Flexible blades on the periphery of the impeller provide the pumping action. While the impeller rotates the liquid between the blades is continuously squeezed out into the discharge port by a machined in cam located inside the pump chamber.
For longevity of the pump, we recommend the impeller and seal be replaced under the following guidelines:
The impeller must be replaced if it is worn out or has been damaged by debris or by running the pump dry. Symptoms of a defective impeller are low pumping pressure and low flow. To replace the impeller remove screws and cover. Pull out the impeller with needle nose pliers or two screwdrivers. Be careful not to dent the pumping chamber with these tools. When inserting new impeller, line up key slot in impeller with the key in the shaft. Use oil on shaft and avoid forcing the impeller onto the shaft. The impeller should also be removed for storage periods to prevent the blades from taking a permanent set.
If water drips from the area where the shaft exits the pump, the seal is defective and must be replaced. While the shaft slinger barrier seal provides a first line of defense, prolonged running of the pump with a leaky seal can destroy the ball bearings of the electric motor. For seal replacement, the pump must be removed from the motor and disassembled in order to gain access to the seal area. The Nitrile seal must be pushed out of the press-fitted position and a new lip seal pressed into place, using a sealant on the outside of the lip seal housing. Refer to exploded view drawings for seal location and part numbers for ordering purposes.
Oberdorfer is part of Gardner Denver, Inc., a leading global manufacturer of highly engineered products. Gardner Denver is headquartered in Milwaukee, Wisconsin, USA and has facilities in more than 30 countries.