Graco Mongoose Series, Instructions - Parts Manual

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Troubleshooting
3A4131H 11
Troubleshooting
1. Follow Pressure Relief Procedure , page 9, before
checking pump.
Problem Cause Solution
Pump does not achieve or maintain
prime Air trapped in inlet line Straighten inlet line to eliminate high
spots.
Worn or contaminated check valves Inspect check valves in fluid end for
cleanliness.
Excessive lift Verify the appropriate lift for the liquid
being pumped. Maximum suction lift
is 5 ft. with water or liquids of similar
specific gravity; though less with
heavier liquids, such as acids. Mount
the pump in a lower position relative
to the chemical container.
Suction fittings not properly tightened Check fittings. Overtightening may
cause restriction. Conversely, if any
leakage occurs, the pump will suck
air and fail to prime.
Split or pinch in inlet tube Inspect inlet tube through its full
length to assure there are no splits at
the connections or other restrictions.
Move objects or equipment which
impinges upon the inlet tube, or
reroute as required to assure a
smooth transition from foot valve to
pump.
Low chemical level Check fluid level in chemical supply
tank.
Insufficient fluid Stroke adjustment set too low Check operation of STROKE %
knob. If pump delivers too low adjust-
able rate, check settings. Readjust as
required.
Worn or contaminated check valves Inspect, clean, or replace as neces-
sary.
Obstruction in inlet line Check inlet line for obstructions, clog-
ging, kinks, or pinch points.
Clogged foot valve screen Clean or replace foot valve screen.
Output (system) pressure too high Relocate the injector to a lower pres-
sure part of the system.
Diaphragm worn or torn Replace diaphragm.
Blown fuse Replace fuse with like kind.