The first reason: sewage lift pump speed is too low
1.Human factors; some users due to motor damage wife, Front analyzer coupled to another motor with a random move, resulting in a small pump flow, head low or even no water;
2.The pump itself of mechanical failure; impeller and shaft fastening nut loose or bent shaft deformation, resulting in movement of the impeller. Direct friction with the pump or bearing damage, are likely to reduce the speed of the pump;
3.Power machine repair ineffective; because the motor windings burned field loss, change in the maintenance of winding turns, wire size, wiring methods.Change or repair the fault does not completely rule out factors also cause the pump speed changes.
The second reason: no water, sewage lift pump inlet and pump body with air
1.Before the start of the sewage pump is not filled with enough water sometimes looks irrigation water from the bleed hole overflow, but the rotation shaft.The air is completely discharged, resulting in a little air left in the pump inlet or in;
2.In contact with the pump inlet reverse flow direction of the horizontal section of the application above 0.5% decrease in the slope, the pump inlet connected to the highest end, not perfectly horizontal. If the upward tilt, will be retained within the inlet air, reduces the pipes and pumps in a vacuum, the impact absorption;
3.Pump packing because long-term use has been worn or packing too loose, resulting in large amounts of water from the packing and shaft sleeve. The gap discharge, the result is on the outside air from these gaps into the interior of the pump, affecting water pumping;
4.Into the water due to long-term potential underwater, wall corrosion holes appear, after the water pump work declining, when these holes. After the holes out of the water, the air from the inlet pipe into the hole;
5.The inlet pipe bends cracks, gaps appeared smiling and pump inlet pipe connection, are likely to allow air intake into the inlet pipe.
The third reason: suction is too big
Some deeper water, some water peripheral terrain is relatively flat at the neglect of the allowable pump suction, and thus cause less or no water no water absorption results. The degree of vacuum at the sewage pump suction port can be established is limited, absolute vacuum suction of water is about 10m high, and the pump can not establish an absolute vacuum. Front analyzer and vacuum through the large, easy to pump water gasification within the pump a job. So each has its maximum allowable centrifugal pump suction, generally between 3-8.5m. When installing the pump only bogey simple convenience.