308116 11
Troubleshooting
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 8.
1.
Relieve the pressure.
2.
Check all possible problems and solutions before
disassembling pump.
Problem
Cause
Solution
Pump fails to operate.
Restricted line or inadequate air
supply.
Clear; increase air supply.
Insufficient air pressure; closed or
clogged air valves, etc.
Open; clean.
Exhausted fluid supply.
Refill; purge all air from pump and
fluid lines.
Damaged air valving mechanism;
stalling.
Service air motor (see 306982 or
307043).
Dried fluid seizure of displacement
rod (13).
Clean, check, or replace throat
packings (5, 24); always stop pump
at bottom of stroke and keep wet-
cup filled with compatible solvent.
Pump operates but output is low on
both strokes.
Restricted line or inadequate air
supply.
Clear; increase air supply.
Insufficient air pressure; closed or
clogged air valves, etc.
Open; clean.
Exhausted fluid supply.
Refill; purge all air from pump and
fluid lines.
Clogged fluid line, valves, etc.
Clear.*
Packing nut (2) too tight.
Loosen (see page 9).
Loose packing nut (2) or worn throat
packings (5, 24).
Tighten packing nut (see page 9);
replace throat packings.
Pump operates but output is low on
downstroke.
Held open or worn intake valve.
Clear; service.
Pump operates but output is low on
upstroke.
Held open or worn fluid piston valve
or packings (20, 23).
Clear; service.
Erratic or accelerated operation.
Exhausted fluid supply.
Refill; purge all air from pump and
fluid lines.
Held open or worn intake valve.
Clear; service.
Held open or worn fluid piston valve
or packings (20, 23).
Clear; service.
* To determine if the fluid hose or gun is obstructed, follow the Pressure Relief Procedure on page 8. Discon-
nect the fluid hose and place a container at the pump fluid outlet to catch any fluid. Turn on the air just enough to
start the pump (about 20–40 psi [0.1–0.3 MPa, 1.4–2.8 bar]). If the pump starts when the air is turned on, the
obstruction is in the fluid hose or gun.
