91
ENG
•
After rinse - The reason for the after rinse
is to remove all loosened dirt and detergent.
•
Disinfection - The disinfection reduces the
number of toxic micro-organisms to an accept-
able level. However, the disinfection does not
guarantee full sterility and is only sensible
after a good cleaning.
• Final rinse - The nal rinse has to be done
with germ-free water with a total hardness
below 5 °D (90 mg/l CaCO3). The nal rinse
water is often used for pre rinse.
7.
Problem solving
Failure Possible cause Solution
There is no suction • Wrong direction of rotation
• Valve in suction line or pressure
line closed
• Synthetic plugs are still in inlet or
outlet
• Insufcient de-aeration
• For self-priming pumps: pressure
on outlet of pump too high
• Change two terminals
• Open valves
• Remove plugs
• De-aerate better
• Open all valves completely,
decrease pressure in discharge
vessel, make provisions so that
no liquid column can be built up
on the outlet of the pump, remove
any non-return valve from the
discharge pipe and, if necessary,
install it directly on the suction of
the pump.
Pump ow is too
low
• There is no suction
• Wrong direction of rotation
• Valves are not opened enough
• Impurities in the pipe work
• Pump draws air
• Air pockets in the suction line
• Wrong motor connection
• See above
• Change two terminals
• Open valves
• Clean pipes
• Stop leakages in suction line, raise
level in suction tank
• De-aerate
• Reconnect in the right way
Pump produces
low pressure
• Wrong direction of rotation
• Cavitation
• Motor is running too slow (fre-
quency converter)
• Wrong motor connection
• Change two terminals
• See below
• Raise frequency
• Reconnect in the right way
Cavitation (pump
makes a cracking
noise, pump hunts
on/off line)
• Friction losses in suction line too
high
• Liquid temperature too high
• Liquid level in suction tank too low
• All valves in suction line must be
completely open, enlarge diameters
• Cool down liquid
• Fill up tank or lower pump
Pump ow too high • Friction losses too low • Close valve in discharge pipe
Pump blocks • Pump wrongly assembled
• Foreign body in the pump
• Disassemble and assemble in the
correct way
• Clean