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820-133 17
PROBLEM
CAUSE SOLUTION
Sprayer
starts but will not suck
paint
Paint
supply empty
Refill and prime pump
Inlet screen clogged
Clean
Inlet valve stuck or damaged
See page 18
Outlet valve stuck
See page 18
Air trapped in hydraulic system
See page 18,
Diaphragm
, step 9
Hydraulic oil level low or empty
See page 14
Wrong grade of hydraulic oil or
wrong
fluid in hydraulic system
Use only Graco approved hydraulic
oil, part no. 218–797
Inlet valve not tight
T
ighten; see page 14
Damaged diaphragm
Replace; see page 18
Sprayer sucks paint but does not
build
up pressure
Pressure
control valve not turned up
Adjust
Outlet
valve stuck, dirty or had worn
parts
See
page 18
Hydraulic oil low
See page 14
Inlet valve leaks
See page 18
Damaged diaphragm
Replace; see page 18
Damaged bypass valve
Replace
Damaged hydraulic system
Return sprayer for repair
Damaged paint pump
Replace
Sprayer sucks paint, builds pres-
sure but pressure drops when gun
No spray tip on gun
Shut of
f sprayer and install tip
sure, but pressure drops when gun
is
triggered
Spray tip orifice too large for the
paint
or worn tip
T
ry a smaller tip or a new tip
Inlet screen clogged
Clean
Optional gun filter clogged
Clean or replace
Optional
gun filter screen too fine for
type
of paint
Install
larger mesh filter
or strain and
thin
the paint
Paint too thick
Thin and/or strain
W
orn outlet valve
Replace; see page 18
Leaking bypass valve
Replace
W
orn or damaged inlet valve
See page 18
Worn or damaged pressure control
valve
See
page 18
Pressure fluctuations
Outlet valve stuck, dirty or worn
See page 18
Leaking or dirty bypass valve
Replace
Dirty
, leaking, worn or damaged
inlet valve
Replace; see page 18
Dirty pressure control knob
Clean or replace; see page 18
Damaged diaphragm, or paint
pump,
or hydraulic system
Return for repair
Paint in hydraulic system
Ruptured diaphragm
Return for repair
Hydraulic oil in paint
Ruptured diaphragm
Return for repair