Low
Capacity |
| Possible
Causes | |
What To Do
| |
|
| Pump speed too slow |
| Check engine speed and
PTO ratio. Consult pump performance curve. Use tachometer on pump if speed is
questioned. |
|
|
| Differential pressure
too high |
| Restriction in discharge
piping or hose is too small. Vapor equalization lines too small or not used. |
|
| |
External by-pass valve stuck open or set too low |
| Re-adjust, repair or replace
valve. |
|
|
| Clogged strainer |
| Clean strainer. |
|
| |
Suction pipe too small or restricted |
| Indicated by pump inlet
pressure dropping several pounds when pump is started. Remove restriction or modify
piping. |
|
|
| Worn blades/vanes |
| Replace blades/vanes.
|
|
| |
Worn sideplates |
| Replace/reverse sideplates.
|
|
| |
Blade/vane sticking |
| Remove blades/vanes and
clean out foreign matter. Check material compatibility or replace blades if swollen.
|
|
| |
Pumping without vapor return |
| Without vapor equalization,
a pump can remove only about 3% of the truck tank capacity per minute without
severe cavitation and capacity loss. |
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