Graco Inc EM390 Troubleshooting Guide, Pressure Relief Procedure, Problem Cause Solution

TROUBLESHOOTING GUIDE

WARNING

Pressure Relief Procedure

To reduce the risk of serious bodily injury, including fluid injection, splashing in the eyes or on the skin, or injury from moving parts, always follow this procedure when you shut off the sprayer, when checking, adjusting or cleaning the system, and when changing spray tips.

1.Engage the gun safety latch.

2.Turn the ON/OFF switch to OFF.

3.Unplug the power supply cord.

4.Disengage the gun safety latch. Hold a metal part of the gun firmly to the side of a grounded metal pail, and trigger the gun.

5.Engage the gun safety latch.

6.Open the fluid pressure drain valve and leave it open until you start the sprayer again.

If you suspect the hose or spray tip is completely clogged or that pressure is not fully relieved after fol- lowing the steps above, VERY SLOWLY loosen the tip guard retaining nut or hose end coupling and relieve pressure gradually. Now loosen the part completely. Clear the tip or hose obstruction.

Check everything in the chart before disassembling the sprayer.

PROBLEM

CAUSE

SOLUTION

Electric motor won't run	Power cord or extension cord un-	Check, reset or replace.
	plugged, or damaged, or building circuit
	breaker or fuse has tripped
	Motor overload switch1 has opened	Unplug power supply cord, relieve pressure, al-
		low motor to cool, clear motor air passages of
		dirt and overspray, decrease pressure.
	Pressure setting too low	Increase pressure.
	Pressure control frozen2 or damaged by	Try to thaw, or replace pressure control.
	over±pressurization3
Electric motor stops while	Power cord or extension cord un-	Check, reset or replace.
spraying	plugged, or damaged, or building circuit
	or fuse is blown
	Motor overload switch1 has opened	Unplug power supply cord, relieve pressure, al-
		low motor to cool, clear motor air passages of
		dirt and overspray, decrease pressure.
	Pressure setting too low	Increase pressure.
	Spray tip or filter plugged	Remove and clean.
	Wrong type extension cord	Use maximum 200 ft. (61 m), 3 wires, 12 gauge,
		grounded extension cord.
Electric motor runs, but low paint	Piston ball check not seating	Service the pump. See page 18.
output or no paint output;
or pump is not stroking
See the PROBLEM, ªNot enough
	Piston packings worn or damaged	Replace the piston. See page 18.
paint pressureº, on page 17, also
	Intake valve ball check not seating	Service the pump. See page 18.
.	Pump is frozen	Thaw2
	Filter element installed upside down	Install element correctly. See page 14 or manual
		307±273.
	Pressure control frozen2 or damaged by	Try to thaw, or replace pressure control.
	over±pressurization3
	Drive assembly damaged	Replace drive housing. See page 21.
	Displacement pump worn or damaged	Replace displacement pump. See page 18.
	Sprayer is not primed.	Prime sprayer. See page 10.

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