Graco TexSpray 235490 Repair Manual page 8

Troubleshooting (Continued)
PROBLEM
Engine operates, but
displacement pump does not displacement pump does not
(Continued) (Continued)
Engine operates, displace-
ment pump operates, but no
material pressure at gun. material pressure at gun
Low fluid delivery
Loss of air control or volume
at gun
Displacement pump output
low on upstroke low on upstroke
8 309662
CAUSE
Connecting rod worn or damaged
Drive housing worn or damaged
Pinion assembly worn or damaged
Flow control is set to PRIME
Fluid system over--pressurized
Gun nozzle/disk is clogged
Material flowing out drain line
Pump is packed out
Siphon hose strainer is clogged.
Engine RPM too low
Flow control set too low
Hose too long or material too
coarse
Material flowing out drain line
Gun nozzle/disk is clogged
Pump is packed out
Gun air passages clogged with
material
Air filter dirty
Air flow sensor dirty or damaged
Piston ball (220) not seating
Piston packings worn or damaged
Siphon hose coupling gasket (1e)
worn or missing.
Pump cylinder o-ring (205) worn or
missing
SOLUTION
Replace connecting rod. See page 14.
Replace drive housing. See page 15.
Service pinion assembly. See page 16.
Set flow control to LOW/MED/HIGH while
triggering gun.
Spraying material is too thick or the mate-
rial hose is too long. Use a less course
material or a shorter hose.
Check and clean nozzle/disk as needed.
Switch to a larger nozzle/disk.
Check for air leaks to dump valve.
Check dump valve for wear, replace as
needed.
Air flow sensor dirty or damaged.
Disassemble and clean pump (see page
8), hose(s) and gun.
Clean or remove strainer
Increase engine speed. See Startup,
procedure in operator manual.
Increase flow control to MED or HIGH
Change to a shorter hose or less coarse
material.
Check drain line for a constant flow of
material when sprayer is operating in
LOW/MED/HIGH mode.
Check for air leaks to prime valve.
Check dump valve for wear, replace as
needed.
Check and clean nozzle/disk as needed.
Switch to a larger nozzle/disk.
Disassemble and clean pump (see page
8), hose(s) and gun.
After releasing gun trigger, make sure
system is fully depressurized before trig-
gering gun again. This helps prevent
material backing into gun passages.
Clean or replace element
Check air filter.
Clean air flow sensor (see page 4) or re-
place as needed.
Clean piston area. See page 12.
Replace packings. See page 12.
Replace or install gasket
Replace o-ring