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Eleven Tips for Fire Pump Troubleshooting and How to Repair and Maintain

Dec 27, 2022
Eleven Tips for Fire Pump Troubleshooting and How to Repair and Maintain
Fire pump does not turn on when starting

Reason: The packing is too tight or the impeller and the pump body are blocked by debris; the pump shaft, bearing, and leakage ring are rusted; the pump shaft is seriously bent. Remedy: Loosen the packing, dredge the water diversion tank: disassemble the pump body to remove debris or rust; correct the bent shaft or replace the pump shaft with a new one.

After starting, the water pump does not produce water

Reasons: There is air in the pump or gas accumulation in the water inlet pipe; the bottom valve is not closed tightly and the water is not filled, the vacuum pump packing is seriously leaking; the gate valve or flap door is not closed tightly. Remedy: remove debris, replace the damaged rubber pad, change the direction of the valve plate; press or replace the new packing, close the gate valve or flap the door; increase the amount of water until there is no air bubbles at the vent plug; replace the Cracked pipe water; reduce the head and press the nozzle of the water pump into the water 0.5 meters.

Insufficient flow

Reasons: the actual head of the fire pump exceeds the allowable head; the speed is not matched or the belt is slipping, and the speed is low; the installation angle of the blade of the axial flow pump is too small; the suction is too high; the bottom valve, pipeline and impeller are partially blocked or the impeller is defective; the outlet pipe Leakage is serious. Remedy: reduce the head, restore the rated speed, remove the dirt on the belt and adjust the belt tightness; adjust the blade angle, lower the installation position of the water pump; tighten the gland, seal the leak of the water pump, compress the packing or replace the packing; remove the blockage, Replace the impeller; replace the leak ring to block the leak.

The flow rate changes from large to small

Reason: The filter screen or bell mouth is gradually blocked by debris; the dynamic water level is lowered, and the submerged water depth of the water inlet pipe is not enough. Elimination method: remove sundries, increase the depth of the bottom valve into the water.

Overhaul and maintenance

1. After the fire pump is out of service, the remaining water in the pump and pipeline should be drained, and the internal soil should be cleaned to prevent the pump body and water pipe from bursting due to the freezing of accumulated water after freezing.

2. The iron castings such as the bottom valve and elbow of the fire pump should be cleaned with a wire brush, and then painted with anti-rust paint before painting, and then put them in a ventilated and dry place in the machine room or storage room after drying custody.

3. If it is driven by a belt, remove the belt, wash and dry it with warm water, and then hang it in a dry place without direct sunlight, and do not store it in a place with oil, corrosion and smoke. Under no circumstances should the belt be stained with oily substances such as engine oil, diesel or gasoline, and do not apply rosin and other sticky substances.

4. Check the ball bearings. If the inner and outer jackets are worn, moved, worn or spotted on the surface, they must be replaced. For those that do not need to be replaced, the bearings can be cleaned with gasoline or kerosene, coated with butter, and reinstalled.

5. Check whether the impeller of the water pump has cracks or small holes, and whether the fixing nut of the impeller is loose. If there is any damage, it should be repaired or replaced. If the impeller wears too much or has been damaged, it should generally be replaced with a new impeller. Partial damage can be repaired by welding, and the impeller can also be repaired with epoxy resin mortar. The repaired impeller should generally undergo a static balance test. Check the clearance at the impeller wear-reducing ring, if it exceeds the specified value, it should be repaired or replaced.

6. For pump shafts that are bent or severely worn, they should be repaired or replaced, otherwise it will cause imbalance of the rotor and wear of related parts.

7. Soak the removed screws in diesel oil, brush them with a steel wire brush, apply engine oil or butter, reassemble them or wrap them in plastic cloth and put them away (it can also be stored in diesel oil) to avoid rust or loss.

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