Troubleshooting Chart - Nordson A7A Product Manual

20
A7A Airless Spray Gun

Troubleshooting Chart

Problem
1. Leaking around nozzle or
nozzle retaining nut
2. Leaking through exhaust
holes in the gun body
directly behind the
fittings
3. Spitting
4. On/Off cycle response
poor or non-existent
Manual 4-6
Possible Cause
Dirty or damaged metal sealing
surfaces
Worn packing cartridge
Dirty or worn ball tip or seat
Long trigger air lines
Air trapped in fluid system
Air piston assembly worn or out of
adjustment
Low air pressure to the air solenoid
Long trigger air lines
High fluid pressure
107 966E
Issued 1/98
Corrective Action
Relieve pressure to the system.
Remove the nozzle retaining nut and
clean or replace the nozzle and the ball
and seat.
Replace the packing cartridge and seal
kit with the appropriate kit. Refer to the
Parts section.
Clean or replace the ball tip and seat.
Mount the solenoid on or as close as
possible to the gun.
Use optional dump valves or air release
valves. Refer to the Options section.
Circulate fluid for several minutes to
purge any air from the system.
Adjust or replace the air piston
assembly.
Increase the air pressure to between
2.7–4.1 bar (40 and 60 psi).
Mount the solenoid on or as close as
possible to the gun.
Reduce the fluid pressure at the pump.
The maximum pressure allowed is
117 bar (1700 psi).
1998 Nordson Corporation
All rights reserved