12-troubleshooting
guide for Boiler Feed Pumps
SL No. |
Problem |
Root cause |
Remedy/Action
to be taken |
1 |
High bearing vibrations What are the reasons for high
bearing vibration in Boiler feed pump (BFP) |
More clearance in
bearing |
Maintain bearing
clearance within the limit as recommended by OEM |
Contaminants/burs in
oil |
Replace the oil |
||
Pump operation in re circulation mode for long time. |
Operate the pump at
the flow > 30% of rated capacity Pump should not be
operated more than 30 min in recirculation mode |
||
Miss alignment for
axial vibrations |
Check & correct
the alignment |
||
Looseness in
foundation bolt or coupling bolts for vertical vibrations |
Tighten the bolts |
||
Imbalance for
horizontal vibrations |
Check & conduct
balancing test at OEM shop |
||
Over load operation |
Operate the Turbine
at or within its maximum capacity |
||
Looseness in
impeller |
Inspect the pump thoroughly
& rectify the errors in impeller fitment |
||
Malfunction of the
vibration sensor |
Get confirm the high
bearing vibrations are due to malfunction, if confirmed ensure tightness of
all connections. |
||
2 |
High bearing temperature
(Journal) What are the reasons for high
bearing temperature in BFP? |
Low lube oil level |
Check for any
leakages, if there arrest the leakages Top up the oil. |
High lube oil
temperature |
Check for cooling
water flow, remove the blockages if any. |
||
Over load operation |
Operate the pump at
or within rated flow |
||
Less clearance in
bearing |
Maintain bearing
clearance within the limit as recommended by OEM |
||
Malfunction of the temperature
sensor |
Get confirm the high
bearing vibrations are due to malfunction, if confirmed ensure tightness of
all connections. |
||
3 |
Cavitation/abnormal sound What are the reasons for
cavitation in Pumps? |
Low suction pressure |
Check the reason for
low suction pressure & Normalise |
High feed water
temperature at pump’s suction |
Reduce the steam
flow to deaerator & maintain the suction temperature as pre-design
pressure. If pump suction pressure is low, it may reach the vapour
temperature leading into steam formation inn pump. |
||
Low deaerator level |
Normalise the deaerator
flow by increasing make up water or process return condensate. |
||
Low deaerator operating
pressure |
Increase &
maintain the Deaerator pressure as per rated pressure |
||
Low suction water |
1.Check for suction
valve throttling & increase the suction water flow 2.Check for clogging
of pump strainer due to any foreign materials. |
||
High flow |
Reduce the flow
& maintain as per OEM design. |
||
4 |
More Balance leak off pressure What is the reason for more
balance leak off pressure in BFP? |
Worn out balance
discs |
Inspect &
replace the discs |
More clearance in
balance & counter balance discs |
Inspect & adjust
the clearance as per OEM manual |
||
More suction
pressure |
Maintain the suction
pressure as per OEM recommended |
||
Blocked balance leak
off pressure impulse line |
Check & clear
the line |
||
Higher pump discharge
pressure |
Maintain the
discharge pressure as per OEM recommended |
||
High discharge flow |
Maintain the
discharge flow as per OEM recommended |
||
Faulty pressure
gauge |
Replace the pressure
gauge |
||
|
|
||
5 |
Low Balance leak off pressure What is the reason for less
balance leak off pressure in BFP? |
Less clearance in
balance & counter balance discs |
Inspect & adjust
the clearance as per OEM manual |
Improperly fitted
balance discs |
Inspect & adjust
the clearance as per OEM manual |
||
Low suction pressure |
Check & increase
the suction pressure |
||
Low discharge
pressure |
Check & ensure
the correct discharge pressure |
||
Leakages in balance
leak off line |
Arrest the leakages |
||
Faulty pressure
gauge |
Replace the pressure
gauge |
||
6 |
Pump overheating What is the reason for pump over
heating? |
High feed water
temperature |
Maintain the feed
water temperature as per design |
Operating the pump
at higher flow |
Optimise the
discharge flow |
||
Operating the pump
at flow < 30% of rated |
1.Increase the flow
beyond 30% 2.Do not operate the
pump with discharge valve closed for long time. |
||
Low suction flow |
Check the strainer
& clean Check the suction
valve & ensure it’s open 100% |
||
Cavitation |
Ensure suction
pressure & temperature are as per design |
||
Bearing failure |
Replace the bearing
or maintain the clearance |
||
Continuous operation
of the pump |
Follow pump change
over schedule. |
||
Internal rubbing due
to improper thermal expansion |
1.Ensure uniform expansion
of pump. 2.Do not start pump
as soon as hot water induced into it. Allow it for some times for uniform
thermal expansion. |
||
7 |
Journal bearing failure What is the reason for BFP pump
bearing failure?? |
No lubrication |
1.Ensure proper oil
level. 2.Follow lubrication
& lubricant replacement schedule. |
Insufficient cooling
& operation of the pump at higher bearing temperatures |
1.Ensure bearing
temperature is in the range of 50 to 70 deg C. 2.Ensure proper
cooling water is flowing in & out of the bearing cooling jacket. |
||
Operating the pump
at lower speed for long time |
Ensure the pump will
be operated at speed >80% to ensure proper splitting of lubricant oil to
bearing liners |
||
Starting of the pump
at lower speed |
Always start the
pump at speed reference > 50% Ensure pump will
attain its 50% speed (1500 rpm) in initial 10-12 seconds, this will protect
the bearing from lack of lubrication at initial lower speed. |
||
Frequent start &
stop of the pump |
Ensure pump will not
be started or stopped frequently |
||
Starting of the pump
with discharge valve opened |
Never start the pump
with discharge valve open to avoid sudden jerk load to the pump, which not
only damages the bearing even harms pumps internals, coupling & motor |
||
Stopping of the pump
with discharge valve opened |
Never stop the pump
with discharge valve open to avoid sudden jerk load to the pump, which not
only damages the bearing even harms pumps internals, coupling & motor |
||
8 |
Insufficient discharge flow or
pressure What is the reason for low
discharge or low discharge pressure from Boiler feed pump? |
Pump is running on
partial load or lesser speed |
Increase the speed |
Discharge valve
throttled |
Ensure 100% opening
of the discharge valve |
||
Suction valve
throttled |
Ensure 100% opening
of the suction valve |
||
Air lock |
Ensure proper priming
of the pump. Keep open drain/vent provided at suction strainer for 3 sec. |
||
ARC (Automatic
recirculation) valve stuck or passing |
Servicing of the ARC
valve |
||
9 |
Frequent tripping of pump
during start up Why does the pump trip during
start up? |
Discharge valve Open |
Close the discharge
valve & start the pump |
Pump jam |
1.Ensure proper
lubrication 2.Ensure uniform thermal
expansion |
||
Electrical related
problems |
Check at Motor &
Panel side and rectify the identified problems |
||
10 |
Excessive Noise & Vibration What are the reasons for
excessive noise & vibrations in pumps? |
Cavitation in pump |
Ensure suction
pressure & temperatures are normal |
Pump air lock |
Ensure proper priming
of the pump |
||
Bearing damage/worn
out |
Inspect and replace if needed |
||
Internal rubbing |
Inspect &
replace damaged internals |
||
Pipe lines
vibrations |
Inspect supports
& rectify if required |
||
11 |
Mechanical seal leakage/Gland
leakage What are the reasons for
Mechanical seal failure in pumps? |
Improper
installation |
Check &
reinstall the seals |
Seals parts damaged |
Check the root cause
& replace the damaged parts |
||
Frequent start &
stop of the pump |
Ensure pump will not
be started or stopped frequently |
||
Worn out shaft
sleeve |
Replace the sleeve |
||
Jerk loads on seals |
Ensure discharge
valve is closed before starting or stopping of the pump |
||
12 |
Pump consuming more power What are the reasons for more
power consumption by Boiler feed pumps? |
Automatic
Recirculation Valve (ARC) passing |
Get done the
overhauling of valve |
Bearing friction |
Maintain required
clearance in bearing |
||
Internal rubbing |
Replace the worn-out
parts |
||
Lesser efficiency of
coupling & motor |
Replace the worn-out
couplings Verify motor load
& efficiency |
||
Higher flow |
Ensure pump is
delivering flow as per design |
||
Lower pump efficiency |
1-Check pump
hydraulic power 2-Check fluid
temperature & suction pressure and ensure both are as per design. 3-Ensure pump’s
discharge pressure is as per design |
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