Graco 3A0732J Manual De Usuario

Troubleshooting 

14

3A0732J

NOTE: Check all possible problems and causes before 
disassembling the pump.

Relieve the pressure before checking or servicing 
the equipment.

Air motor will not run.

Damaged air valve (214). 

Replace or service air valve (214). See 
page 18.

Damaged pilot valve (213).

Replace pilot valves (213). See page 20.

Air continuously exhausting around air 
motor piston rod.

Damaged u-cups (207).

Replace piston rod u-cups (207). See 
page 22.

Air continuously exhausting from muf-
fler.

Damaged air valve plate (305) or cup 
(312).

Replace or service air valve (214). See 
page 18.

Air motor “bounces” at top of stroke.

Damaged bottom pilot valve (213).

Replace bottom pilot valve (213). See 
page 20.

Air motor “bounces” at bottom of 
stroke.

Damaged top pilot valve (213).

Replace top pilot valve (213). See page 
20.

Icing inside motor.

Air 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 supply; 
closed or clogged valves.

Clear line or increase air supply. Check 
that the valves are open.

Obstructed fluid hose or gun; fluid hose ID 
is too small.

Open, clear*; use hose with larger ID.

Fluid dried on the displacement rod (119).

Clean; keep the packing nut wet-cup filled 
with Graco throat seal liquid (TSL).

Pump operates but does not prime.

Held open or worn ball check valves or pis-
ton packings.

Clear valve; replace packings. See page 
16.

Worn suction hose o-ring (38).

Replace suction hose o-ring (38).

Pump operates, but output is low on 
both strokes.

Restricted line or inadequate air supply; 
closed or clogged valves.

Clear line or increase air supply. Check 
that the valves are open.

Obstructed fluid hose or gun; fluid hose ID 
is too small.

Open, clear*; use hose with larger ID.

Worn packings in displacement pump.

Replace packings. See page 16.

Pump operates, but output is low on 
downstroke.

Held open or worn ball check valves or pis-
ton packings.

Clear valve; replace packings. See page 
16.

Erratic or accelerated pump speed.

Exhausted fluid supply.

Refill and prime.

Held open or worn ball check valves or 
packings.

Clear valve, replace packings. See page 
16.

Fluid being pumped is visible in the 
packing nut wet-cup.

Worn throat packings.

Tighten packing nut. 

Replace throat packings. See page 16.

Bad spray pattern.

Clean or repair spray gun or tip.

See G15/G40 air-assisted gun manual or 
Silver Plus airless gun manual.