Doseuro D Series - Dosing Pumps Troubleshooting Tables; A Type Piston Pumps Troubleshooting Table

XMPE0PCG125NST020 1st edition - 2020
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20 - DOSING PUMPS TROUBLESHOOTING TABLES
20.1 - A type piston pumps troubleshooting table
TROUBLESHOOTING
Problems
Causes
Solutions
Low discharge pressure
Low flow rate
1 - Clogged suction system:
Clean the suction filter. Check
the suction pipe and the feed
tank for obstructions or partially
closed valves
2 - Worn pressure relief valve
seat:
Check the pressure relief valve, if
the liquid leaks - switch-off the
pump and check
Low discharge pressure
Low flow rate
3 - pump not completely
primed (air bubble in the
suction pipe):
Excessive suction height, comply
with the NPSHr value, install a
suction diaphragm
Low discharge pressure
Low flow rate
4 – incorrectly connected
motor:
Check the motor plate again for
the correct wiring sequence.
Check the phases.
5 - dirty pump valves:
Inspect valve units. Clean or
replace the components if
required.
6 - Damaged piston seal
gasket.
Air intake through piston
seals. Scratched piston
Replace the seal gaskets or the
piston
7 - air entering the pump head
Check the presence of inlet air in
the suction pipe. Check junctions
between pipes, seals around the
valve rods, and the connections
of the instruments.
Check the diameter and piping
route.
8 - insufficient suction
pressure
Increase suction pressure.
Reduce the suction height or
increase the liquid level in the
feed tank.
9 - Winding pipe route with the
presence of chokes; pipe
inside diameter smaller than
the valve passage area;
Check diameter and piping route
Fluid leak measured by the
hole located under the lantern
Damaged piston seal gasket.
Scratched piston
Replace the seal gaskets or the
piston.
Excessive noise
1 - air entering the pump head
Check the presence of inlet air in
the suction pipe. Check junctions
between pipes, seals around the
valve rods, and the connections
of the instruments.
If the air is entering through the
stuffing box, adjust or replace it.
2 - foreign material inside the
valve
Inspect valve units. Clean or
replace the components if
required.
3 - excessive lifting of valves
Replace worn parts
4 - pressure relief valve or
other accessories in the
discharge pipe causing noise
A quick closing of the valve,
solenoid valve, or cock will
produce a water hammer. This