12
306–694
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 causes and problems before
disassembling the pump.
Pump fails to operate
Restricted line or inadequate air supply
Clear; increase air supply.
Obstructed fluid hose, gun, or
Open, clear.*
dispensing valve
Exhausted fluid supply
Refill; purge all air from pump and fluid lines.
Fluid dried on displacement rod
Clean; always stop pump at bottom of stroke;
keep wet–cup 1/2 filled with compatible solvent.
Damaged air motor
Service air motor (see 307–049 or 307–304).
Pump operates but output
Restricted line or inadequate air supply
Clear; increase air supply.
low on both strokes
Obstructed fluid hose, gun, or
Open, clear.*
dispensing valve
Exhausted fluid supply
Refill; purge all air from pump and fluid lines.
Air in displacement pump and hose
Reprime.
Check valves need adjustment
Adjust (see manual 307–862).
Packing nut too tight or too loose
Adjust (see page 11).
Worn throat packings
Replace (see manual 307–862).
Pump operates but output
Held open or worn intake valve
Clear; service. See manual 307–862.
low on down stroke
Pump operates but output
Held open or worn fluid piston valve
Clear; service. See manual 307–862.
low on up stroke
or packings
Erratic or accelerated
Exhausted fluid supply
Refill; purge all air from pump and fluid lines.
operation
Packing nut too tight
Adjust (see page 11).
Check valves need adjustment
Adjust (see manual 307–862).
Held open or worn intake valve
Clear; service. See manual 307–862.
Held open or worn fluid piston valve
Clear; service. See manual 307–862.
or packings
CAUSE
PROBLEM
SOLUTION
*
To determine if the fluid hose or gun is obstructed,
relieve the pressure. Disconnect 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 [140–280 kPa, 1.4–2.8 bar]). If
the pump starts when the air is turned on, the obstruction is in the fluid hose or gun.
