Troubleshooting
3A6823A
13
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.
Replace packing.
Pump stroking, but no fluid moving.
Air in pump.
Prime pump. See page 11.
Worn or damaged check valve seals.
Rebuild check valves.
Pneumatic motor will not run.
Damaged pneumatic valve (217).
Replace or service pneumatic valve (217).
See page 17.
Damaged pilot valve (219).
Replace pilot valves (219).
See page 19.
Fluid valve (K) shut.
Open fluid valve (K).
See page 8.
Air continuously exhausting around
pneumatic motor plunger.
Damaged u-cups (203 and 233).
Replace plunger u-cups (203 and 233).
See page 20.
Air continuously exhausting from muffler.
Damaged pneumatic valve plate (305) or
cup (312).
Replace or service pneumatic valve (217).
See page 17.
Pneumatic motor “bounces” at top of
stroke.
Damaged bottom pilot valve (219).
Replace bottom pilot valve (219). See
page 19.
Pneumatic motor “bounces” at bottom of
stroke.
Damaged top pilot valve (219).
Replace top pilot valve (219).
See page 19.
Icing inside motor.
Pneumatic motor operating at high pres-
sure or high cycle rate.
Reduce pressure, cycle rate, or duty cycle
of motor.
Excessive moisture in pneumatic supply
line.
Reduce dew point of compressed air in
moisture coalescing filter.
Pump fails to operate.
Restricted line or inadequate air supply;
closed or clogged valves.
Clear line or increase air 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 output is low.
Worn packings in pump.
Replace packings. See page 15.
Held open or worn check valves or pack-
ings.
Clear valve; replace packings.
See page 15.
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 15.
Fluid being pumped is visible on the pack-
ing nut.
Worn packings.
Replace packings. See page 15.