I. Pump Installation
The installation and calibration of the water pump is the crucial first step. Although the pump unit is calibrated at the factory, transportation and assembly can lead to varying degrees of deformation or loosening. Therefore, the pump must be calibrated during installation.
1. Installation Steps
(1) Remove grease and dirt from the base and place it on the foundation.
(2) Check the base's levelness with a level. Wedging with wedges is permissible.
(3) Pour cement into the base and anchor bolt holes.
(4) After the cement has hardened, check the base and anchor bolt holes for looseness. Tighten the anchor bolts appropriately and recheck the levelness.
(5) Clean the supporting surface of the base, the pump feet, and the motor feet, and install the pump and motor onto the base. (6) Check and adjust the alignment of the pump and motor shaft centers. Ensure the pump and motor shaft centers are aligned; the vertical and horizontal difference between the outer diameters of the two couplings should not exceed 0.1mm. Thin shims can be used for adjustment to ensure concentricity. Leave a 2-3mm gap between the end faces of the two couplings.
2. During pump installation, the following must be noted:
(1) The actual suction head of the pump must be lower than its allowable suction head.
(2) The pump inlet pipe should be as short and straight as possible, and should not bulge upwards or be higher than the pump on a horizontal line to avoid increased cavitation and reduced efficiency during operation.
(3) The pump outlet pipe should be appropriately enlarged and as close as possible to the water surface. Excessive height or depth will increase power consumption. For long-distance transport, a larger pipe diameter should be used. The pump pipeline should have a dedicated support; the weight of the pipeline should not be placed on the pump to avoid damaging it.
(4) The distance between the pump foot valve or inlet and the bottom and edge of the water source shall not be less than the diameter of the inlet pipe, and the inlet pipe depth shall not be less than 0.5 meters. When installing two or more pumps, the distance between the foot valves or inlet pipes shall not be less than twice the outer diameter of the foot valves or inlet pipes.
(5) The check valve on the discharge pipeline should be installed outside the gate valve. Check valves should be installed on pumps with a head of 20 meters or more.
(6) The diameter of the pulley should be determined based on the rotational speed. When calculating the pulley diameter using the formula, the factor of belt slippage should be considered, and the calculated value should be adjusted appropriately.
II. Pump Start-up, Operation, and Stopping
The start-up, operation, and stopping of the pump shall be strictly carried out according to the operating procedures.
1. Start-up
(1) When starting the pump, before connecting the motor and pump, confirm whether the rotation direction of the motor is correct and whether the pump rotates flexibly.
(2) Close the gate valve on the discharge pipeline.
(3) Fill the pump with water, or use a vacuum pump to prime it.
(4) Connect the power supply. After the pump reaches normal speed, gradually open the gate valve on the discharge pipe and adjust it to the required operating conditions. With the gate valve on the discharge pipe closed, the pump should not operate continuously for more than 3 minutes.
2. Operation
(1) During startup and operation, carefully observe the instrument readings, bearing temperature rise, packing leakage and heating, pump vibration, and noise to ensure they are normal. If any abnormalities are found, address them promptly.
(2) The bearing temperature should not exceed 80℃, or be more than 40℃ higher than the ambient temperature.
(3) The packing should be normal, and leakage should be small and uniform.
(4) When using machine oil for lubrication, the bearing oil level should be maintained at the normal position, neither too high nor too low. If the level is too low, replenish the lubricating oil promptly. When using grease lubrication, change the oil after 300 hours of operation for a new pump, and then every 1500 hours thereafter. When the ambient temperature is below 0℃, oil lubrication is suitable; when the ambient temperature is above 0℃, grease lubrication is suitable.
3. Stopping
Gradually close the gate valve of the discharge pipe and then disconnect the power supply.
III. Common Faults and Troubleshooting
1. Pump not discharging water. First, fill the pump with water to remove air from the pipe; second, lower the pump's suction head to within its normal suction range; third, check the foot valve and impeller to see if the foot valve is open and not clogged with mud or sand, and clean the impeller if necessary; fourth, check the power system to see if the power cord is connected incorrectly and if the rotation direction is correct.
2. Low pump output. First, insufficient speed; check the power system. Second, severe wear on the sealing ring and impeller inlet ring; replace the sealing ring and impeller. Third, debris in the foot valve and impeller; disassemble and inspect the foot valve and impeller and remove the debris. Fourth, if the pump's suction head exceeds its rated suction head, the water level will drop during operation, causing the pump to operate in an over-suction head state. Measurements show that a pump exceeding its suction head by 0.5 meters will experience a 20% reduction in water output. Measures should be taken, such as lowering the pump or considering water level drops during installation, to ensure the suction head remains within the normal range. Fifth, high resistance in the outlet pipeline leads to significant water loss; the pipeline should be shortened or its diameter increased. Sixth, if the pump head is too high, a pump with a suitable flow rate should be selected based on the actual head and calculated water loss.
3. Abnormal internal pump noise. First, the flow rate is too high; reduce the opening of the outlet gate valve or increase the resistance in the outlet pipe to reduce the flow rate. Second, air may be leaking; check the suction pipeline for leaks and seal them. Third, the suction head is too high; reduce the suction height.
4. Overheating bearings cause excessive pump vibration. First, there may be insufficient lubrication; add lubricating oil. Second, the pump shaft may be bent. If pump vibration is detected, it should be repaired immediately. If the pump shaft is not severely bent, it can be straightened with a manual screw straightener and reused. If the bending is severe, it should be replaced immediately. Thirdly, if there is no axial clearance in the bearing, add a paper shim to the bearing cover end face for adjustment. Fourthly, if the drive belt is too tight, adjust its position.
5. Motor overheating and high power consumption. Firstly, the packing is too tight; loosen the packing gland appropriately. Secondly, if the impeller is worn too much, the pump output will increase; replace the impeller or appropriately close the outlet gate valve to increase the resistance of the outlet pipe and reduce the flow rate.
IV. Pump Maintenance and Care
1. In addition to strictly following the installation and operation manual, two points should be noted when using the pump: Firstly, never rely solely on "experience." For example, when the pump's foot valve leaks, some operators, for convenience, fill the inlet pipe with dry soil before each start-up, then fill with water to flush the soil to the foot valve to stop the leak. This method seems simple and easy, but it is not advisable. When the pump starts working, sand and soil from the foot valve will enter the pump along with the water, wearing down the impeller, pump casing, and shaft, severely affecting its service life. The correct approach is to inspect the foot valve; if it cannot be repaired, replace it. Secondly, any faults should be addressed promptly; never allow the unit to operate with defects. For example, if the pump shaft packing is severely worn, add more packing immediately; otherwise, it will leak air. Air leakage from the pump shaft packing not only increases energy consumption but also causes cavitation, accelerating impeller damage and directly affecting the pump's service life. Furthermore, if the pump vibrates violently, stop it immediately for inspection; otherwise, if the pump is bent or deformed, a safety accident may occur.
2. After a period of use, the pump unit and pipelines should undergo the following maintenance:
(1) Drain all remaining water from the pump and pipelines.
(2) If disassembly is convenient, remove the pump and pipelines and clean them thoroughly. (3) Inspect the ball bearings. Replace them if the inner and outer races are worn, there is play, the balls are worn, or there are spots on the surface. If they are still usable, clean them with gasoline or kerosene and then apply grease before storing.
(4) Inspect the impeller for cracks or small holes, and check if the impeller fixing nut is loose. Repair or replace if damaged. Check the clearance at the impeller anti-friction ring; if it exceeds the specified value, repair or replace it.
(5) If the pump and pipeline are not disassembled, seal the outlet with a cover to prevent debris from entering.
(6) When the drive belt is not in use, remove it, wash it with warm water, dry it, and store it in a place away from direct sunlight, oil, corrosive substances, and fumes. Under no circumstances should the belt come into contact with machine oil, diesel, gasoline, or other oily substances. Do not apply rosin or other sticky substances to the belt. Before use, remove any white powder from the belt contact surfaces.
(7) Clean all screws and bolts with a wire brush and coat them with machine oil or soak them in diesel oil for storage.
