Graco Inc 313516C important safety instructions Spray Pattern Troubleshooting

Problem

Cause

Solution

Fluid needle will not trigger.

Loose or missing fluid needle stop

Replace stop or tighten setscrew.

(29) or setscrew (30).

Air leaking around piston (3).

Replace o-ring (8) or piston.

Swollen piston o-ring (8).

Replace o-ring. Do not immerse

piston in solvent.

Insufficient air pressure on trigger.

Increase air pressure or clean air

line.

Plug (19) is in incorrect fluid port.

Move plug to fluid port consistent

with manifold plumbing, unless

you are using gun in a circulating

system. If you are, all fluid ports in

gun and on manifold should be

open.

Fluid does not shut off.

Worn o-ring (11) or (9).

Replace o-ring.

Piston cap (4) not fully tightened.

Tighten piston cap until it bottoms

out.

Spring (6) not in place.

Check spring position.

Swollen piston o-ring (8).

Replace o-ring. Do not immerse

piston in solvent.

Problem

Cause

Solution

Fluid flow is fluttering while spray-

Fluid nozzle is not tight enough.

Tighten fluid nozzle to 60 in-lb

ing.

(6.8 N•m).

O-ring (36) is missing or dam-

Replace o-ring.

aged.

Fluid filter is clogged.

Check fluid filter.

Fluid flow fades while spraying

Fluid pressure is too low, causing

Raise fluid pressure at source or

high viscosity fluids.

fluid flow to reduce when gun is

use a smaller fluid nozzle.

elevated.

Pattern becomes off-set or heavy

Air cap horn holes plugged or

Clean air cap horn holes with

on ends.

damaged.

non-metallic item such as a tooth-

pick, or replace air cap.

Gun fluid pressure is too high with

Using needle/nozzle kit with too

Use needle/nozzle kit with larger

gun triggered.

small orifice.

orifice.

Fluid system will not operate at

There is no fluid regulator, or air

Add low pressure fluid regulator,

low enough fluid pressure [below

regulator on pressure pot is not

or add more sensitive low pres-

10 psi (70 kPa, 0.7 bar)].

sensitive enough at low pressures.

sure air regulator on pressure pot.

22

313516C