Commissioning of Centrifugal Pumps

1.
Commissioning of Centrifugal
Pumps
Method 1
Start up
1. Check lubrication (bearings). Check oil reservoir level.
2. Open the cooling water valves (inlet and outlet).
3. Open the seal fluid line.
4. Open the heating valve (prime and heat). When the valve is hot, close the valve.
5. Close all drains.
6. Open the suction valve.
7. Prime the pump.
8. Open the recirculation line.
9. To start the engine.
10. Slowly open the discharge valve.
11. Observe and listen to the pump and motor to ensure they are operating correctly.
12. Check the discharge pressure.
13. Check for the presence of a leak in the seal fluid.
14. Adjust the seal fluid valve to ensure it is flowing at an appropriate rate.
15. After verifying that the pump is operating correctly, close the recirculation valve.
Stop
1. Open the recirculation valve.
2. Slowly close the discharge valve until it is completely closed.
3. Stop the engine.
4. Open the heating valve if required to maintain operating temperature.
5. Close the cooling water valves.
6. Close the suction valve.
7. Open the drain valve.
Source: https://www.youtube.com/watch?v=jW3qycJlhLQ
Method 2
Verifications before Commissioning
1. Do not operate the centrifugal pump below the minimum design flow or with the suction
or discharge valves closed.
2. Always disconnect and lock out power to the motor before performing any installation or
maintenance work.
3. Check the direction of rotation of the pump.
4. Thoroughly sweep and clean the system to remove dirt in the plumbing system.
5. Bring variable speed motors (if installed) to design speed as soon as possible.
6. Generally if the temperature of the pumped fluid will exceed 200°F (93°C), then warm up
the pump before start-up.
7. Circulate a small amount of fluid through the pump until the casing temperature is within
100°C of the fluid temperature.
Start up
1. Open the suction valve.
2. Open any recirculation or cooling line.
3. Completely close or partially open the discharge valve, depending on system conditions.
5. Slowly open the discharge valve until the pump reaches the desired flow.
6. Check the discharge pressure.
7. If the pump fails to achieve the correct pressure, perform the following steps:
a. Stop the engine.
b. Prime the pump again.
c. Restart the engine.
8. Monitor the pump while it is operating.
a. Check the temperature of the bearings, vibration and noise.
b. If the pump exceeds normal levels, then immediately stop the pump and correct
the problem.
9. Repeat steps 6 and 7 until the pump works properly.
Source: https://www.enggcyclopedia.com/2011/10/centrifugal-pump-start-up-procedure/
Method 3
Start up
1. Pumps are made to work with liquid.
2. Pumps must be primed.
3. Make sure the discharge valve is in the correct position.
4. Allows the pump to “climate”
5. Always check the oil level of the pump, engine and auxiliary systems.
6. Make sure you have pressure gauges on the suction and discharge of the pump.
7. Have a thermometer on hand.
After Commissioning
1. Check that you have discharge pressure on the pressure gauge; if there is no pressure, turn
off the pump.
2. Open the discharge valve slowly, the pressure should drop at some point. If this does not
happen then stop the pump because some downstream valve must be closed.
3. Close the Bypass valve slowly.
4. If the discharge pressure drops to zero or begins to change erratically, then the pump has
lost prime and you will need to stop it.
5. Look for leak points and depending on their magnitude, risk and position, stop the pump.
6. Check mechanical seals, gaskets, labyrinth seals and baffles. If there is any abnormal
condition, stop the pump.
7. Measure bearing temperature with the appropriate equipment.
Stop
1. Close the discharge valve slowly to 95% - 100% (radial pumps) or 50% (axial pumps).
Remember that the closing time is related to the Water Hammer, the longer the closing
time, the lower the Water Hammer.
2. Turn off the pump.
3. Remember to keep the discharge and suction valve closed while the pump is not
operating.
4. Turn off auxiliary systems for seals (if any), lubrication, etc.
Fountain:
http://gabaypumps.blogspot.com/2016/06/encendiendo-y-apagando-una-bomba.html
Grades
1. The pump discharge valve must be closed on most radial and mixed flow pumps. (Higher
horsepower pumps often require the discharge valve to be opened approximately 10%).
Source: Volk, Pump Characteristics and Applications.
2. Radial and mixed flow pumps have an ascending power curve as the flow rate increases,
and the power is minimum at closed discharge. Therefore, these types of pumps must be
started with the discharge valve completely closed, or with an opening of 5%. Thus the
power consumption will be minimal. Starting up with the discharge closed will not cause
the pump to explode, contrary to what many think, but it will make it difficult to open the
valve due to the pressure differential to which the valve gate will be subjected, therefore a
5% open is usually better.
Fountain:
3. Axial and axial flow pumps have a power curve that is maximum in the shutoff (closed
discharge) and decreases as we “Move to the right” in the flow axis. These pumps cannot
be started with the discharge closed because the power consumption can even be DOUBLE
or more than the power that would be required at the operating point for which it was
selected. Not many companies will be willing to purchase a 2,000 HP motor when only 900
HP is required at the duty point. These pumps are then started with the discharge open at
50% or more. The best piping designs give these pumps a minimum flow bypass line so
that the pump runs with the main valve 100% closed but the bypass valve 100% open, so
they do not risk overloading the motor during the match.
Fountain:

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