Problem Solving - Johnson Pump SPX MDR Manual De Instrucciones

5 Problem solving

18
Table 2: Possible causes of pump failures.
Problem Possible causes
Air pockets in suction lines
Lack of prime (when suction
head is negative)
Air pockets inside the pump
Insufficient suction head
No flow
Slipping magnet coupling
Wear or damage of parts
No liquid in the pump
Air entrainment or air pockets
Run reverse
Underfeed
Excessive piping loss
Impeller is clogged with foreign
materials
Excessive specific gravity and/or
viscosity
Excessive power
Excessive wear of pump parts
Excessive wear of motor
bearings

Problem solving

Remedy
Check piping of suction lines
and work out all air
Prime again
Work out all air
See paragraph 2.2.1 "Maximum
suction lift (Hs)"
Excessive specific gravity and/or
viscosity - check against original
specification (see paragraph 2.7
"Viscosity and specific gravity
limits")
Replace parts
Check liqud level in the tank. If a
foot valve is installed on the
suction line make sure that it is
properly sealed. Fill the pump
again.
Air entrainment or air Check
joint sections of suction lines.
Work out all air
Check direction of rotation
Reduce suction line length or
increase diameter
Remove foreign materials
Check viscosity and specific
gravity against pump per
formance (see paragraph 2.7
"Viscosity and specific gravity
limits").
Replace parts
Replace bearings/motor
MDR/EN (1206) 3.2