Troubleshooting

Troubleshooting

Check all possible remedies in the troubleshooting charts before disassembling the gun.

Some improper patterns are caused by the improper balance between air and fluid. Refer to Spray Pattern Troubleshooting, page 19.

General Troubleshooting

Problem

Cause

Solution

 

 

 

 

 

 

Fluid leakage through venting holes.

Worn packings or needle.

Replace needle assembly. (14)

 

 

 

Air leakage through venting hole.

Worn o-ring (23) or gasket (15).

Check and replace parts as needed.

 

 

 

Air leakage from back of gun.

Worn o-rings (22, 23).

Replace o-rings.

 

 

 

Air does not trigger.

Piston stem is disconnected from

Replace piston assembly.

 

main body of piston assembly (20).

 

 

 

 

Air does not shut off.

Piston assembly not seating properly.

Clean/service piston assembly.

 

 

Replace worn or swollen o-rings.

 

Broken return spring (29).

Replace spring.

 

Swollen o-ring (22).

Replace o-rings.

 

Worn piston stem o-rings (25, 26).

Replace o-rings.

 

Bottom gasket (16) failed.

Replace gasket.

 

 

 

Fluid leakage from front of gun.

Fluid needle (14) dirty, worn, or dam-

Clean or replace fluid needle.

 

aged.

 

 

Dirty or worn diffuser-seat (10).

Clean or replace diffuser-seat.

 

 

To improve sealing while spraying

 

 

lightweight materials and sealing life

 

 

while spraying acid catalyzed materi-

 

 

als, use optional SST ball and plastic

 

 

seat.

 

 

 

Fluid is present at air cap holes.

Spray tip is leaking,

Verify that retainer (8) or RAC air cap

 

 

assembly (30), are tight. If so, replace

 

 

spray tip (9).

 

Diffuser-seat (10) is insufficiently

Tighten diffuser-seat.

 

 

 

tightened.

 

 

 

 

311052E

17

Page 17
Image 17
Graco Inc 288046, 311052E, 288217, G40 important safety instructions General Troubleshooting, Problem Cause Solution