Troubleshooting
3A6831G
15
Troubleshooting
1.
before checking or repairing pump.
2.
Check all possible problems and causes before dis-
assembling pump.
Problem
Cause
Solution
Air bubbles in fluid.
Fluid inlet line is loose.
Tighten.
Fluid leaking.
Loose fittings.
Tighten fittings.
Worn seals.
Adjust packing (if leak persists, replace
packing).
Pump stroking, but no fluid moving.
Air in pump.
Prime pump.
Worn or damaged check valve seals.
Rebuild top and bottom poppets.
Pneumatic motor will not run.
Damaged pneumatic valve (217).
Replace or service pneumatic valve (217).
See page 20.
Damaged pilot valve (219).
Replace pilot valves (219).
See page 23.
Air continuously exhausting around
pneumatic motor plunger.
Damaged u-cups (203).
Replace plunger u-cups (203).
See page 26.
Air continuously exhausting from muffler.
Damaged pneumatic valve plate (305) or
cup (312).
Replace or service pneumatic valve (217).
See page 20.
Pneumatic motor “bounces” at top of
stroke.
Damaged bottom pilot valve (219).
Replace bottom pilot valve (219). See
page 23.
Pneumatic motor “bounces” at bottom of
stroke.
Damaged top pilot valve (219).
Replace top pilot valve (219).
See page 23.
Icing inside motor.
Pneumatic motor operating at high
pressure or high cycle rate.
Reduce pressure, cycle rate, or duty cycle
of motor.
Reduce dew point of compressed air in
moisture coalescing filter.
Pump fails to operate.
Restricted line or inadequate air/gas
supply; closed or clogged valves.
Clear line or increase air/gas supply.
Check that the valves are open.
Obstructed fluid line; fluid line ID is too
small.
Open, clear*; use line with larger ID.
Pump operates but does not prime.
Held open or worn check valves or
packings.
Clear valve; replace packings.
See page 17.
Pump operates, but output is low on both
strokes.
Restricted line or inadequate air/gas
supply; closed or clogged valves.
Clear line or increase air/gas supply.
Check that the valves are open.
Obstructed fluid line; fluid line ID is too
small.
Open, clear*; use line with larger ID.
Worn packings in pump.
Replace packings. See page 17.
Pump operates, but output is low on
downstroke.
Held open or worn check valves or
packings.
Clear valve; replace packings.
See page 17.
Erratic or accelerated pump speed.
Exhausted fluid supply.
Refill and prime.
Held open or worn check valves or
packings.
Clear valve, replace packings.
See page 17.
Fluid being pumped is visible on the pack-
ing nut.
Worn packings.
Tighten packing nut.
Replace packings. See page 17.
