MVP ATC-4000 Series, Repair Manual, Page: 21 / 55

ATC Chopper Gun Operations Manual
Page | 21
32. Install the packing housing assembly (cartridge assembly) into the front of the gun head.
33. Press the diffuser seat as far as it will go into the front of the gun head.
34. Using a
5
16
nut driver, adjust the packing seat until it is snug, then just a little more.
35. Insert the catalyst spool valve assembly into the back of the gun head.
36. Using the two screws, attach the cylinder assembly to the gun head.
37. Attach the gun head and cylinder to the handle.
Troubleshooting
Air Assisted AT Gun Troubleshooting
Symptom Possible Cause Remedy
Air leaking form
exhaust port on
back of handle
while trigger is in
OFF position O-ring material worn or cut Replace O-rings
O-rings on catalyst piston worn or cut
O-rings on trigger valve worn or cut
Air leaking from
exhaust port on
back of handle
while trigger is
either OFF or ON O-rings on trigger valve worn or cut Replace O-rings
O-rings on catalyst valve and/or
material piston worn or nicked
Catalyst leaking
from catalyst tip
while gun is sitting
(not being
triggered)
O-rings on catalyst valve worn or cut
Replace O-rings
Catalyst leaks
from weep hole on
catalyst side of
gun
O-rings on catalyst valve worn or cut
Replace O-rings
No catalyst is
coming from gun
Catalyst air piston is not actuating
Check for clogged catalyst air passages (small
holes underneath back cylinder)
Note There is more than one passageway
from holes
Plugged catalyst restrictor (Allen
screw with orifice located in front of
catalyst valve)
Clean and clear orifice
Plugged catalyst passageway in head
of gun or catalyst tips Inspect, clean, and clear passageways
No catalyst flow to gun
See Slave Pump troubleshooting for your
system