PROBLEM

CAUSE

SOLUTION

 

 

 

Paint leaks into wet±cup

Throat packings are worn or damaged

Replace the packings. See page 16.

 

 

 

Excessive surging from spray gun

Spray tip or fluid filter is plugged

Disassemble and clean.

 

 

 

 

Spray tip too big or worn

Change the spray tip.

 

 

 

 

Paint too viscous

Thin the paint.

 

 

 

 

Wrong type hose

Use minimum 50 ft (15.2 m), static±free nylon

 

 

hose (wire braid hose is unacceptable).

 

 

 

Not enough paint pressure

Pressure setting too low

Increase pressure.

 

 

 

 

Spray tip too big or worn

Change the spray tip.

 

 

 

 

Pressure control frozen2 or damaged by

Try to thaw, or replace pressure control.

 

over±pressurization3

 

 

Displacement pump worn or damaged

Replace the displacement pump. See page 16.

 

 

 

Tails or fingers in spray pattern

Pressure setting too low

Increase pressure.

 

 

 

 

Fluid outlet filter is dirty or clogged

Clean the filter. See page 12 or manual 307±273.

 

 

 

 

Spray tip too big or worn

Change the spray tip.

 

 

 

 

Fluid supply is low or empty

Refill and prime the pump. See page 10. Check

 

 

fluid supply often to prevent running the pump

 

 

dry.

 

 

 

 

Paint too viscous

Thin the paint.

 

 

 

 

Wrong type hose

Use minimum 50 ft (15.2 m), static±free nylon

 

 

hose (wire braid hose is unacceptable).

 

 

 

Paint runs or sags

Spray tip too big or worn

Change the spray tip.

 

 

 

Spitting from gun

Air in fluid pump or hose

Check for loose connections at pump intake and

 

 

tighten. Then prime the pump. See page 10.

 

 

 

 

Tip partially clogged

Clear the tip. See page 11.

 

 

 

 

Fluid supply is low or empty

Refill and prime the pump. See page 10. Check

 

 

fluid supply often to prevent running the pump

 

 

dry.

 

 

 

Static sparking from the gun

Spray or work being sprayed is not prop-

Correct problem before continuing. Follow the

 

erly grounded

warning section, FIRE OR EXPLOSION HAZ-

 

 

ARD on page 3.

 

 

 

1The 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.

2Freezing results from failure to replace the water±base paint or flushing water with mineral spirits, and usually causes permanent damage to the pressure control.

3Over±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.

DISPLACEMENT PUMP

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. See Fig 12.

1. Flush the sprayer. Relieve pressure.

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).

307-735 15

Page 15
Image 15
Hitachi EM 490 dimensions Displacement Pump, Removing the Pump. See Fig