Accident Handling and Precautions for Circulating Water Pumps

Accident Handling of Circulating Water Pumps

1. When the running pump encounters the following malfunctions, stop the faulty pump first and then start the standby pump:
   • When the impeller of the water pump is damaged.
   • When the bearing temperature of the water pump and motor exceeds 90°C, or when there is smoking or fire.
   • When the vibration value of the water pump and motor exceeds 0.10mm and is accompanied by a metal friction sound.
2. When the running pump has the following malfunctions, start the standby pump first and then stop the faulty pump:
   • When the gear of the inlet or outlet butterfly - valve gearbox of the circulating pump gets stuck or is damaged.
   • When the leakage at the inlet side of the circulating water pump or the packing is so severe that it affects water intake.
   • When the motor temperature rises, but the temperature increase does not reach 60°C and the temperature does not reach 80°C.
   • When the inlet strainer of the water pump is blocked.
3. Reasons for the circulating water pump losing pressure and failing to pump water:
   • The water level in the circulating water suction well is low.
   • There is air trapped in the pump.
   • The inlet side of the water pump or the packing leaks.
   • The inlet strainer is dirty and severely blocked.
   • The impeller is damaged.
   • The inlet butterfly valve is not opened or is damaged.
   • The rotation direction of the motor is incorrect.

• Add industrial water as soon as possible to restore the water level in the suction well to normal. When the water level is low, try to avoid switching pumps as much as possible.
• Tighten the packing to eliminate the leakage point. If it cannot be eliminated and it affects the normal operation of the equipment, take measures to try to eliminate it.
• Switch pumps and clean the strainer.
• If the impeller is confirmed to be damaged, stop the pump and wait for maintenance.
• Check and confirm that the inlet valve is open. If it is damaged, try to repair it.
• If the rotation direction of the motor is confirmed to be incorrect, contact the electrical department for handling.

4. Common malfunctions, causes, and treatment methods of circulating water pumps:
   • Malfunction (1): Failure to start
     • Causes:
       • Motor malfunction or problems in the electrical system.
       • Foreign objects enter the rotating parts, causing jamming.
       • Bearing malfunction, getting stuck.
       • The starting conditions are not met.
     • Treatment:
       • Check the motor and the electrical system.
       • Clean out foreign objects.
       • Replace the bearing.
       • Check one by one according to the starting conditions.
   • Malfunction (2): Insufficient output
     • Causes:
       • There are foreign objects on the suction side.
       • The impeller is damaged.
       • The outlet valve is improperly adjusted.
       • The rotational speed is low.
       • Air is inhaled.
       • Cavitation occurs.
     • Treatment:
       • Clean the strainer, impeller, and suction inlet.
       • Replace the impeller.
       • Readjust the outlet valve.
       • Find out the reason for the low rotational speed.
       • Raise the suction water level or place floating objects such as wooden rafts.
       • Raise the suction water level or adjust the operating conditions.
   • Malfunction (3): Overload
     • Causes:
       • The bearing is damaged; there are debris in the pump.
       • The rotating parts are damaged, and the motor is operating with a single - phase fault.
       • The packing gland is too tight.
       • The voltage drops.
     • Treatment:
       • Replace the bearing and remove the debris.
       • Repair the rotating parts, motor wiring, and switches.
       • Loosen the packing gland.
       • Check the power supply.
   • Malfunction (4): Abnormal vibration and noise
     • Causes:
       • The coupling is not concentric, and the bearing is damaged.
       • The water level in the suction pool is low, and the outlet pipeline has an impact.
       • Cavitation occurs.
       • Foreign objects are blocking or the impeller is damaged.
       • The shaft is bent, and the rotor is unbalanced.
       • The coupling bolts are poorly connected.
       • The foundation bolts are loose, or the foundation is not firm, and the rotating parts are loose.
     • Treatment:
       • Realign and replace the bearing.
       • Raise the water level above the minimum level, eliminate the occurrence of vortices, and check and eliminate adverse effects.
       • Raise the suction water level or adjust the operating conditions.
       • Clean out foreign objects and replace the damaged parts.
       • Straighten the shaft and eliminate the imbalance.
       • Re - fix or replace the bolts.
       • Tighten the bolts or reinforce the foundation, and repair the loose parts.

Start - up, Shutdown, and Accident Handling of Condensate Pumps

Start - up of Condensate Pumps and Precautions

1. Pre - start inspection
   • Check that the pump body is intact. (For equipment after maintenance, check whether the motor housing is well - grounded and test that the motor insulation is qualified.)
   • Check whether the positions of the pump and system valves are normal.
   • The coupling can be turned flexibly, and the oil quality and level of the bearing are normal.
   • Check that the water - seal valve, outlet valve, air valve, and inlet valve of the pump are open, and an appropriate amount of cooling water is flowing out.
2. Start - up
   After the pre - start inspection is normal, close the operating switch of one condensate pump. Pay attention to:
   • The ammeter reading should instantaneously reach the maximum and then return to the rated value within 5 seconds. If so, the condensate pump starts normally; otherwise, stop the pump immediately and find out the reason.
   • After the pump starts, the pressure of the condensate water main pipe, current, bearing sound, vibration, oil quality, oil level, and temperature should be normal. There should be water droplets dripping from the packing, and it should not overheat.
   • After the inspection is normal, move the interlock key of the running pump to the working position and the interlock key of the standby pump to the engaged position.

Shutdown of Condensate Pumps and Precautions

1. Inspection
   • Check that the water - seal valve, outlet valve, air valve, and inlet valve of the standby pump are open, and there is cooling water flowing out from the packing.
   • The oil quality of the bearing is qualified, and the oil level is normal.
   • Disengage the interlock switch of the running pump and start the standby pump.
2. Precautions after start - up
   • After checking that the standby pump starts normally, stop the original running pump. Move the interlock key of the new running pump to the working position and the interlock key of the standby pump to the engaged position.
   • If the pump is found to reverse after shutdown, immediately close the outlet valve or the inlet valve.
   • If the start - up switch of the standby pump cannot be closed, report to the superior. After the problem is fixed, stop the standby pump.

Accident Handling of Condensate Pumps

1. When the running pump has the following malfunctions, stop the faulty pump first and then start the standby pump:
   • The bearing temperature rises above 70°C or smokes.
   • The motor smokes or catches fire.
   • There is a clear metal friction sound inside the water pump or the motor.
   • The impeller of the water pump is damaged.
2. When the running pump has the following malfunctions, report to the operator first, then start the standby pump and stop the faulty pump:
   • The motor temperature rises, but does not reach 80°C or the temperature increase does not reach 60°C.
   • The bearing temperature of the water pump and motor rises, but does not reach 90°C.
   • The leakage at the inlet side of the water pump or the packing is so severe that it affects the pump operation.
   • The vibration of the water pump and motor exceeds 0.06mm.
   • The pump vaporizes and affects water pumping.
3. Reasons for the condensate pump losing pressure or failing to pump water:
   • The water level in the condenser hot well is on the low side.
   • The flange of the inlet - side gate valve of the water pump, the packing, or the air valve of the pump packing chamber leaks.
   • The rotation direction of the motor is incorrect.
   • The impeller of the water pump is loose or damaged.
   • The pump experiences vaporization.
   • The inlet gate plate falls off.

• When the water level in the hot well is low, adjust it with the condensate water recirculation valve or use softened water to make up the water to the normal level.
• Add packing, adjust the packing seal water, and tighten the screws to try to eliminate the leakage.
• If the rotation direction of the motor is confirmed to be incorrect, contact the electrical department for handling.
• If the impeller is confirmed to be loose or damaged, stop the pump and wait for maintenance.
• If the pump vaporization is confirmed, stop the pump and put it back into operation after the vaporization is eliminated.
• If the inlet gate plate is confirmed to have fallen off, report to the shift supervisor and wait for instructions.

4. Common malfunctions, causes, and treatment methods of condensate pumps:
   • Malfunction (1): Failure to start
     • Causes:
       • Motor malfunction or problems in the electrical system.
       • Foreign objects enter the rotating equipment, causing jamming.
       • Bearing malfunction, getting stuck or being too tight.
     • Treatment:
       • Check the motor and the electrical system.
       • Clean out foreign objects.
       • Repair the bearing.
   • Malfunction (2): Insufficient output or no water output
     • Causes:
       • Air leaks in the negative - pressure part.
       • The impeller is damaged, and the rotation direction is reversed.
       • The valve is improperly adjusted, or the valve cores of the inlet and outlet valves fall off.

         

       • The water level in the condenser is too low.
     • Treatment:
       • Find and eliminate the air - leakage points.
       • Replace the impeller or reverse the motor wiring to adjust the rotation direction.
       • Readjust the outlet valve or repair the faulty valve.
       • Adjust the water level in the condenser.
   • Malfunction (3): Overload
     • Causes:
       • The motor is operating with a single - phase fault.
       • The bearing is damaged.
       • There are debris in the pump.
       • The rotating parts are damaged.
       • The packing gland is too tight.
       • The voltage drops.
     • Treatment:
       • Check the motor wiring and switches.
       • Replace the bearing.
       • Remove the debris.
       • Repair the rotating parts.
       • Loosen the packing gland.
       • Check the power supply.
   • Malfunction (4): Abnormal vibration and noise
     • Causes:
       • The coupling is not concentric.
       • The bearing is damaged.
       • The shaft is bent, and the rotor is unbalanced.
       • The coupling bolts are poorly connected.
       • The foundation bolts are loose, or the foundation is not firm.
       • The rotating parts are loose.
       • The motor is faulty.
     • Treatment:
       • Realign.
       • Replace the bearing.
       • Straighten the shaft and eliminate the imbalance.
       • Re - fix or replace the bolts.
       • Tighten the bolts or reinforce the foundation.
       • Repair the loose parts.
       • Repair the motor.

1. Why is an air pipe installed on the condensate pump?

2. Why is the packing of the condensate pump sealed with condensate water?

3. Why is a recirculation installed for the condensate pump?