Troubleshooting - Graco Merkur 313255F Instructions Manual

Troubleshooting

Troubleshooting
Relieve the pressure before checking or servicing
the equipment.
F
Problem
Pump fails to operate.
Pump operates, but output is low on
both strokes.
Pump operates, but output is low on
downstroke.
Erratic or accelerated pump speed.
Fluid being pumped is visible in the
TSL reservoir.
* To determine if the fluid hose or gun is obstructed, relieve the pressure. Disconnect the fluid hose and place a con-
tainer at the pump fluid outlet to catch any fluid. Turn on the air just enough to start the pump. It the pump starts when
the air is turned on, the obstruction is in the hose or gun.
18
NOTE: Check all possible problems and causes before
disassembling the pump.
Cause
Restricted line or inadequate air sup-
ply; closed or clogged valves.
Obstructed fluid hose or gun; fluid
hose ID is too small.
Fluid dried on the displacement rod.
Dirty, worn, or damaged air motor
parts.
Restricted line or inadequate air sup-
ply; closed or clogged valves.
Obstructed fluid hose or gun; fluid
hose ID is too small.
Worn packings in displacement
pump.
Held open or worn ball check valves
or piston packings.
Exhausted fluid supply.
Held open or worn ball check valves
or packings.
Worn throat packings.
Solution
Clear line or increase air supply.
Check that the valves are open.
Open, clear*; use hose with larger ID.
Clean; always stop the pump at the
bottom of its stroke; keep the wet-cup
1/3 filled with Graco throat seal liquid
(TSL).
Clean or repair air motor. See manual
312796.
Clear line or increase air supply.
Check that the valves are open.
Open, clear*; use hose with larger ID.
Replace packings. See manual
312794.
Clear valve; replace packings. See
manual 312794.
Refill and prime.
Clear valve, replace packings; see
manual 312794.
Replace throat packings. See manual
312794.
313255F