Nozzle Installation; Maintenance; Troubleshooting - Nordson A7A Customer Product Manual

Nozzle Installation

Remove the nozzle nut from the end of the gun.
Install your nozzle in the nozzle nut, then screw the
nut onto the gun. Tighten the nozzle nut securely.

Maintenance

Flush the gun periodically to keep it clean and free
of contaminants. As required, disassemble and
clean the gun and replace any worn parts.

Troubleshooting

WARNING: Allow only qualified personnel to perform the following tasks. Follow the safety
instructions in this document and all other related documentation.
These procedures cover only the most common problems. If you cannot solve the problem with the
information given here, contact the Nordson Finishing Customer Support Center at (800) 433- 9319 or your
local Nordson representative for help.
Problem
1. Leaking around nozzle
or nozzle retaining nut
2. Leaking from weep
holes
3. Spitting
4. On/Off cycle response
poor or gun not
opening or closing
E 2006 Nordson Corporation
Possible Cause
Dirty or damaged nozzle or seat
sealing surfaces
Worn packing cartridge
Dirty or worn ball and seat
Actuating or trigger air lines too
long
Air trapped in fluid system
Air piston assembly worn or out of
adjustment
Low air pressure to the solenoid
valve
Trigger air lines too long
Fluid pressure too high
A7A Modular Automatic Airless Spray Gun
NOTE: Make sure the nozzle and seat sealing
surfaces are clean before installing the nozzle.
Make sure the trigger air is clean and dry. If you
are operating the gun at high cycle rates for long
periods of time, install an air lubricator in the air
supply line. This will extend the life of the air piston
seal.
Corrective Action
Tighten the nozzle nut. If the leak
persists, relieve system pressure.
Remove the nozzle nut and clean the
nozzle and seat sealing surfaces. If
the leak persists, replace the nozzle
or seat (the ball tip and seat are a
matched set and must be replaced
together).
Replace the packing cartridge with
the appropriate kit. Refer to Parts.
Clean or replace the ball and seat.
Mount the solenoid on or as close as
possible to the gun.
Purge air from system by opening the
drain valve until no air bubbles are
seen, or spraying until spitting stops.
Make sure the pump is not siphoning
air into the fluid system.
Adjust or replace the air piston
assembly.
Increase the air pressure to between
2.7- 4.1 bar (40- 60 psi).
Mount the solenoid on or as close as
possible to the gun.
Reduce the fluid pressure. The guns
will not close if their maximum
working pressure is exceeded.
7
Part 1072609- 02