Displacement Pump - Graco EM 490R EM 490 Instructions-Parts List Manual

PROBLEM
Paint leaks into wet–cup
Excessive surging from spray gun Spray tip or fluid filter is plugged
Not enough paint pressure
Tails or fingers in spray pattern
Paint runs or sags
Spitting from gun
Static sparking from the gun
1
The electric motor has an over–temperature switch
which automatically resets upon cooling. If it opens and
the electric motor shuts itself off, unplug the power supply
cord and let the sprayer cool for 30 to 60 minutes. Always
use the lowest pressure setting needed when spraying.
2
Freezing results from failure to replace the water–base
paint or flushing water with mineral spirits, and usually
causes permanent damage to the pressure control.
WARNING
To reduce the risk of serious bodily injury, follow the
Pressure Relief Procedure Warning on page 14
before checking or repairing any part of the spray
system. Unplug the sprayer!
Removing the Pump.
1. Flush the sprayer. Relieve pressure.
CAUSE
Throat packings are worn or damaged
Spray tip too big or worn
Paint too viscous
Wrong type hose
Pressure setting too low
Spray tip too big or worn
Pressure control frozen
over–pressurization
Displacement pump worn or damaged
Pressure setting too low
Fluid outlet filter is dirty or clogged
Spray tip too big or worn
Fluid supply is low or empty
Paint too viscous
Wrong type hose
Spray tip too big or worn
Air in fluid pump or hose
Tip partially clogged
Fluid supply is low or empty
Spray or work being sprayed is not prop-
erly grounded

DISPLACEMENT PUMP

See Fig 12.
SOLUTION
Replace the packings. See page 16.
Disassemble and clean.
Change the spray tip.
Thin the paint.
Use minimum 50 ft (15.2 m), static–free nylon
hose (wire braid hose is unacceptable).
Increase pressure.
Change the spray tip.
2
or damaged by Try to thaw, or replace pressure control.
3
Replace the displacement pump. See page 16.
Increase pressure.
Clean the filter. See page 12 or manual 307–273.
Change the spray tip.
Refill and prime the pump. See page 10. Check
fluid supply often to prevent running the pump
dry.
Thin the paint.
Use minimum 50 ft (15.2 m), static–free nylon
hose (wire braid hose is unacceptable).
Change the spray tip.
Check for loose connections at pump intake and
tighten. Then prime the pump. See page 10.
Clear the tip. See page 11.
Refill and prime the pump. See page 10. Check
fluid supply often to prevent running the pump
dry.
Correct problem before continuing. Follow the
warning section, FIRE OR EXPLOSION HAZ-
ARD on page 3.
3
Over–pressurization results from (1) using less than 50
ft (15.2 m) of nylon spray hose, (2) from using a wire braid
spray hose, (3) from adding a shutoff device between the
pump outlet and the spray gun, (4) from attaching a spray
hose to the pressure drain valve, or (5) from using a
clogged or incorrectly assembled filter.
2. Hold the intake valve (222) steady with a wrench and
unscrew the adapter (38).
3. Unscrew the hose (52).
4. Use a screwdriver to push the retaining spring (33)
aside, and then push out the pin (34).
5. Loosen the locknut (112) and unscrew the pump (58).