8/13/2019 Troubleshooting of Demin Plant
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Troubleshooting of DM plant
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Defects Causes Remedies
Decrease in capacity betweentwo successive regenerations
a. Increase in ionic load
b. Flow recorder defective
c. Insufficient chemicals used
d. Resin dirty
e. Plant being used intermittently
f. Channelling in bed
g.Resin fouled
h.Resin deteriorated
i. Resin quantity insufficient in unit
Check by analysis
Check
Check
Give prolonged backwash
void this
Check and ensure uniformdistribution !collection
If cation" give #Cl wash$ if anion" resin
give alkaline brine treatment
Check and replace charge
Check and top up
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Treated quality not upto thestandard
a. Cation e%hausted
b. nion e%hausted
c. &i%ed bed e%hausted
d. &' resin not in uniform mi%ed state
e. (ome valves like backwash leaking
f. )a slip from cation high
g. (i*+ slip from anion high
h. ,nit idle
i. ,nit not sufficiently rinsed
-. %cessive!low flow rate
k. Channelling
l. Resin fouled
m.
Resin deteriorated
Check
Check
Check
Repeat air mi% and rinse
Check
Check raw water analysis$ change in)a!/ and (i*+!/ ratio$ use morechemicals
Check raw water analysis$ change in)a!/ and (i*+!/ ratio$ use morechemicals
Check
Rinse to satisfactory quality
d-ust to between unit min!ma% flowrate
Check and ensure uniformcollection!distribution
Check resin and give alkaline brine!#C0 treatment
Check resin and replace
8/13/2019 Troubleshooting of Demin Plant
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Mixed bed quality not good a. Resin not separated during backwash properly
b. ir mi% not proper
c. Final rinse not proper
d. (ome valves may be leaking and contaminatingthe treated water
Give e%tended backwash aftere%hausting the bed
Repeat
Repeat
Check and e%amine
High residual C! fromdegasser
a. It can be due to choked suction filter of degasserair blower
b. Improper air flow to the degasser
c. 1egasser blower not in operation
d. ir seal not fitted!broken resulting in shortcirculating of air
Check and clean filter
Check damper" speed of blower"
discharge pressure
Check and operate blower
Check and replace fitting
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"nit rinse ta#es long time a. Flow rate too high
b. ,nit e%hausted
c. 'ackwash valve passing
d. nion resin organically fouled
e. &' air mi% not satisfactory
f. cid!alkali pockets formed in unit
Increase flow rate
Regenerate unit
Check and rectify
Give alkaline brine treatment
Carry out air mi% once again
Faulty design check and rectify./emporarily backwash 2followed by airscour if &'3 and rinse again
$low rate too less a. Choked valve and suction strainer of pump
b. Cavitation in the pump
c. 0ow inlet pressure
d. 1istribution or collecting system choked
e. Resin trap at outlet choked
f. Control valve shut due to low off4take
Check
Check
Check4pump
Check
Check and clean
Increase off4take
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%ressure drop across the bedincreasing day by day
a. 1efective valves
b. Packed resin bed and resin fines present
c. Collecting system choked
d. Pressure gauge defective
Check
Give e%tended backwash with openmanhole and scrap off fines from topsurface of the resin
Check" repeat backwash
Check and rectify! replace
$looding in degasser a. 5ery high air flow rate
b. Packed tower chocked due to dirt or broken
packing material
Reduce air flow rate by ad-ustingdamper
*pen and check
Resin being lost a. %cessive backwash pressure
b. Faulty collecting system
c. Inlet strainer damaged
Check inlet pressure and reduce if
necessary
%amine same for breakage
Check and replace
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&'ector not wor#ing a. 0ow power water pressure
b. ir lock in the unit
c. Choked or defective valves
d. -ector no66le may be choked
e. /oo much back pressure from the unit
f. 'ulge in pipe lining
Check
'ackwash 7 open air release
%amine and rectify
Check
Check for chokage of collectingsystem$ passage of inlet!outlet valves
Check and rectify
(ncorrect reading rota)meters
a. Chocked orifice lines!orifice
b. 1irty glass and float
Check and clean
check and clean
(mproper reading from flowrecorder integrator
a. Choked impulse lines!orifice
b. 1P transmitter requires recalibration
c. 0eakage in signal tube between transmitter andpanel
d. 0ow air pressure for 1P transmitter or recorder
Check and clean
Recalibrate
Check
Check
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*evel electrodes system formeasuring and dilution tan#
not functioning properly
a. Improper contact between electrodes and controlcabling
b. (horting of the two electrodes due to moisture orany foreign material
c. Improper working of the level controllers
Check contact and rectify
Check and dry the contacts of moistureand dirt
Check
*ea#age from acidin'ection+unloading+transferpumps
a. Improper ad-ustment of the mechanical seal
b. 0ow strength of sulphuric and presence of ferroussulphate
Check and ad-ust
Check concentration and takeappropriate action
Corrosion in concentrated
acid tan#s and lines
a. 0ow concentration of sulphuric acid
b. 0ining of #Cl tank!pipe line damaged
Check silica gel breather in acid
storage tank and replace silica gelcharge if e%hausted
Rectify
(mproper opening andclosing of pneumatically
operated valves
a. 1efective solenoid valves
b. 0eakage in airline from solenoid valve to the
respective control valve.
c. Improper contact of micro switch giving falseindication to panel
d. Fused mimic lamp giving false indication to thepanel
Check
Check
Check
Check
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(mproper operation of acertain regeneration cycle
a. 1efective relays in the control circuit Check and replace relays
,olid state programme notfunctioning properly
a. /he controller can be kept in 8hold8 due to thereasons e%plained under operation
b. Improper operation of the controls for thecontroller
c. 1efect in the inside of the controller
Remove conditions which cause 8hold8of controller
Press test switch 7 check the completecycle
Check the instruments thoroughly frominside. &eanwhile" operation may becontinued by using bypass toggle
switches