Troubleshooting
B 5-2
Part 1022914G03
E
2007 Nordson Corporation
Common Problems
Problem
Possible Cause
Corrective Action
1. Pump fails to start or
stops while operating
and fails to restart
No compressed air supply, or air
pressure too low
Check the air supply at the drop-leg
drain valve. Make sure the air
regulator is working correctly.
Blockage in fluid system
Check for flow from each component
and hose, working from the spray
device to the pump, as follows:
1. Shut off the air to the pump and
relieve the hydraulic pressure.
2. Break the connection.
3. Turn on the air to the pump. If the
pump starts, the blockage is in
the component or hose after the
broken connection.
Pump revisions A
−
C: Air valve
spool stuck in middle position, or
air pilot actuator or three-way
valve cartridge damaged or
sticking
Press and release the top button on
the shuttle valve mounted on the
front of the air valve, then press and
release the bottom button on the
shuttle valve. Repeat this process,
listening for the sound of the air valve
spool hitting its stop each time it
changes direction. If the spool does
not shift and hit the stops, replace the
actuator and three-way valve
cartridges.
Check the air supply for
contamination. Rebuild the air valve
if necessary.
Pump revisions D and above: Air
valve spool stuck in middle
position, or air pilot actuator or
valve components damaged or
sticking
Remove air pilot valve components
from upper or lower cylinder heads.
Clean and and inspect components,
replace any that are worn or
damaged. Check the air supply for
contamination. Rebuild the air valve
if spool is sticking.
2. Excessive or constant
air leakage from air
motor or air valve
Worn U-cup seal in underside of
lower cylinder head
Stop the pump during an upstroke
and check for air leaking around the
connecting rod. Replace the U-cup
seal if it is leaking.
O-rings sealing air valve to
cylinder heads leaking
Check for air leaking at the air
valve-to-cylinder head joint. Replace
the O-rings if they are leaking.
O-rings sealing cylinder to cylinder
heads leaking.
Check for air leaking around the
cylinder heads. Replace the O-rings
if they are leaking.
Air valve seals worn
Replace the seals.
Air piston seal worn or damaged
Replace the air piston.
Continued...
