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Flexible Impeller pump max flow 15.3 GPM max pressure 34.6 PSI

Flexible Impeller Pump - N305M

These Flexible Impeller pumps are made of high quality bronze of maximum corrosion resistance. All shafts consist of stainless steel grade 303. Top of the line models have ball bearings and mechanical seals while others have bronze or carbon bearings and lip type seals. Impellers are made of Neoprene Rubber. Nitrile impellers are available as an option. 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. Pump will operate when mounted in any position.

Impeller and seals should be replaced under the following conditions:

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 weep hole or from the area where the shaft exits the pump, the seal is defective and must be replaced. Prolonged running of the pump with a leaky seal can destroy the motor bearings resulting in catastrophic pump failure. For seal replacement, the pump must be removed from the motor and disassembled in order to gain access to the seal area. Where mechanical seals are used, both components (stationary and rotating member) must be replaced at the same time. Refer to exploded view drawings for seal location and part numbers for ordering purposes.


Performance is based on full voltage supply. Use direct lines. Do not drain voltage with other electrical equipment on same circuit. Lower voltage reduces performance and overloads motor. Use adequate wires size and length to maintain supply voltage.