Preventive Maintenance for CP by Eng. Amer Hamdan
Published on: Mar 4, 2016
Transcripts - Preventive Maintenance for CP by Eng. Amer Hamdan
Preventive Maintenance Introduction
For Centrifugal Pump Systems
Prepared by: Eng. Amer Hamdan
General Maintenance Dept.
Building Maintenance and Facilities Section.
Pump rooms, Pumps and their accessories, Valves, Pressure Gauges , Pipe works, Control Panels,
Pressure Tanks, Filters, Waters Tanks, suction lines, Discharge lines , all of mentioned items have
been tested and concluded the following:
1-Pump room covers are not sealed enough from dangerous insects, and same the concrete under the
cover is broken, which is not safe of technicians and staff.
2- Vision is not clear at some pump rooms (Lights Missing).
3- Submersible pumps at pump rooms and other open areas are not covered and exposed to
sediments and clay accumulation the thing that harms the submersible pump.
4- Some Pumps are leaking.
5- Some suction and discharge valves are leaking
6- Corrosion has been noticed in pump, base plate, pipes, valves and elbows
7-Some pumps are connected to operate directly on manual mode
8- In many cases there are a lot of tees and elbows and valves on suction lines.
9- Discharge and suction valves are not positioned as per operation instruction on certain
throttling degree and end user staff changing it while pump operating, which harms the pump.
10- Pumps in some sites are over sized and are not matching system requirements, which results
in poor duty point. ( pipes: type, length ,elevation, diameter)
11- float switch is not positioned to maintain recommended minimum fluid level at tanks
12-Noise and vibration are above normal levels in many pump sets.
13- Electrical motors need to be cleaned from sand and dust
14- Concrete base (Foundation) and base plate need renewing and leveling.
15- Pump are misaligned with respect to base plate and foundation.
16- There is no cautions lists describing DO’s and DON’T’s to be considered while dealing with
17- In many sites pump name plate are painted ,so it is not possible to identify the pump
specifications and serial number on the name plate.
Main Failure Causes:
1-Manufacturers defects : Negligible, almost misalignment of the internal parts of the pump
2- System Design:
a- Pump will be affected if the minimum liquid level makes NPSHa < NPSHr
(NPSH: Net Positive Suction Head)
b- Pipes level ( Suction, Discharge) is not matching pump level.
c- Pump is oversized or smaller capacity pump has been selected.
d- Pump selection is not matching system requirements : Pipe– size ,type ,length are not matching the
system or the required duty point.
e- Suction side full of tees and elbows and valves
f- Submersible pump is exposed to clay accumulation and sediments without adding screen to protect
g- Using smaller size bolts for base plate.
h- misalignment of pump ,motor ,Concrete Foundation and base plate.
3- - Operational faults:
a-To keep the pump operation on manual mode until it pumps all water from tank and runs on dry
b- Pump to exceed daily recommended operational time
c- To keep stand by pump without operation for long time
d- In case of not cleaning tanks –especially- open tanks, then sands ,clay, solid contents and salt
with accumulate at the tank and will harm pump internal parts
e- Changing throttling degree of the discharge and suction valves
f- Changing the float switch position below the minimum required liquid level
g- Forget to grease pump for long time.
1- Apply safety standards to all pump rooms including double sealing covers for all underground pump
rooms, and contact pits control dept. for routine site visits.
2- Attach operation instruction by manufacturer to each pump set.
3- Routine cleaning for tanks.
4- Using special non-clogging impeller submersible pumps or cover the pit with a screen for pump
5-Performing periodical fluid analysis and solid contents analysis
6- Changing mechanical seal in case of leakage
7- replacing bearing upon manufacturer recommendation or when noise and vibration exceed certain
8-Aligning the pump and motor to pump foundation and base plate.
9- Check suction and discharge lines from blockage.
10- Check float switch position as per pump manufacturer recommendations and project
11- In charge staff to use instrumentation of flow meter, Pressure gauges, Vibration meter, noise
meter, Volt and Amber meters.
12- Data base for all pumps including the following:
a- Pump type, Manufacturer and Serial number; for correct spares request
b- Hydraulic design specifications
c- Data sheet (Manufacturer)
d- Maintenance and operation manual
e- Dimensional pump drawing including parts and its codes
f- Spare Parts list
g- Inspection and maintenance historical data book
Preventive Maintenance System
Preventive Maintenance CP:
The aim of this study is to activate PM routine check list to reduce pump failure and guarantee
that operate smoothly without any problem, the thing that will be reflected on maintenance costs.
Actions to activate PM for CP:
1- Contractual agreement with specialized hydraulic works contractor to perform PM activities.
2-Location survey to all pumps at Municipality sites.
3-Establishing Pumps data base and update it with cooperation with the contractor
4- Performing PM inspection and services according to a periodic schedule, and record repeated
5- Provide PM schedule sheet near each pump set ,describes all test performed by contractor and
Technical Aspects to be monitored (PM):
1- Pump performance (Head H, Flow Q) and check if it is matching with manufacturer data sheet:
a- Suction pressure Ps b-Discharge pressure Pd c- Motor Speed rpm d- Power Hp, KW.
2- Vibration & Noise
3- System Characteristic analysis (Pipes + Suction & Discharge Valves)
4- Monitor pump leakage
5- Monitor the motor (Voltage, Amber, Temperature), and keep it clean, make sure motor speed is
ok with pump performance and duty point
6- Check Pump parts temperature (Bearing)
7-Monitor oil or grease leakage
8-Check suction and discharge lines blockage
9-Check pressure gauges, pressure switch and pressure tank
10-Monitor float switch and float valve
12-Record fluid analysis results ,salinity and solid contents especially for open tanks
13- Check Automatic operation mode circuit ,operate stand by pump for 5 minutes
Benefits of PM for Centrifugal Pumps
If preventive maintenance considered as a major part of comprehensive maintenance works for
centrifugal pumps within a time frame, so the results will be as following:
1- Protecting CP from the following:
a-Pump performance problems
(Head and pressure resulting)
b- Motor malfunctions
d-Mechanical seal breakage
f- Impeller problems
g-Pump casing corrosion or pits
h- System problems( Pipes + Valves)
i- Float switch and float valve problems
2- Reduction of corrective maintenance actions
3-Reducing spare parts replacement requests
4-Reducing complains and service cut off
5-Saving 35%-40% of total maintenance cost for
Periodical PM testsPeriod
Monitoring Water level in TanksDaily
Monitoring Noise & VibrationDaily
Monitoring water leakageDaily
Pets control serviceMonthly
Check pressure gauges & Pressure TankMonthly
Monitoring Pressure SwitchMonthly
Check float valve and float switchMonthly
Monitoring oil or grease leakage from bearing boxMonthly
Monitoring pump parts temp. (Bearing temp.)Monthly
Clean the pump and pump roomMonthly
Make sure that motor performance is matching pump duty pointMonthly
Monitoring electrical motor temp.Monthly
Check automatic operating mode circuit +operate stand by pump 5
Check valves throttling position degreeMonthly
Preventive Maintenance Check list
Measure Motor performanceQuarterly
Measure Pump PerformanceQuarterly
Keep tanks cleanQuarterly
Check suction and discharge line if blockedQuarterly
System characteristic analysisHalf year
Perform Fluid analysis, salinity and solid contentsYearly
Painting Pump ,base plate, valves and elbows and renew concrete
Prepared by: Eng. Amer Ismail
General Maintenance Dept.
Building Maintenance and Facilities Section.