Oberdorfers 401M models feature high quality bronze construction along with 303 grade stainless steel shafts in order to maximize corrosion resistance. Ball bearings and mechanical seals are found on top of the line models, while others have bronze or carbon bearings and lip type seals. Optional nitrile impellers are available, with neoprene rubber as standard. Flexible blades on the periphery of the impeller provide the pumping action. Impellers rotate the liquid between the blades and is continuously squeezed out into the discharge port by a machined in cam located inside the pump chamber.
Either direct drive with flexible coupling or pulley drive can be used. Make sure both flexible coupling halves are properly aligned. When using pulley, do not over-tighten belt.
Direction of shaft rotation determines inlet and outlet ports. (see line drawing)
Pump will operate satisfactorily when mounted in any position. DO NOT RUN DRY. Rubber impeller pumps generate high rubbing friction unless lubricated by liquid pumped. Lack of liquid will cause impeller to burn up.
Liquids compatible with neoprene can be pumped including fresh and salt-water solutions and mild chemicals. Do not pump severe solvents or acids. When possible, flush the pump with fresh water after each usage. Nitrile impellers can handle oil-contaminated water and kerosene at reduced impeller service life.
Extremes of cold and heat will affect impeller life. Limits of 40°F to 180°F should be observed. Do not allow liquid in pump to freeze. Drain pump by loosening cover screws. Use methyl alcohol based anti-freeze compounds such as Zerex, Shell Zone, Pyro Permanent, Permagard, or Dowgard.
Suction lift of 15 feet is possible when impeller is wet. Suction lines must be air tight in order for pump to self-prime. A foot valve at beginning of suction line is recommended.