Graco 3A0868G important safety instructions QDA1, QDB1

System Errors

Alarm and Description	Cause	Solution
R4	There is too little restriction in the system.	• Check that the system is fully
Ratio High Error		loaded with material.
The mix ratio is higher than		• Check that the supply pump’s
the set tolerance for an A to B
		cycle rate is set properly.
component volume compari-
son.		• Check that the spray tip/nozzle is
		properly sized for the flow and
		application, and that it is not
		worn.
		• Check that the fluid regulator is
		set properly.
	If the alarm occurs during start up, after	Restrict gun needle travel to slow
	purging, the flow rate was probably too	down the initial fluid delivery rate until
	high.	fluid hoses are loaded with material.
	If the alarm occurred after you were spray-	Adjust component A and B fluid sup-
	ing for some time, the pressures from the	ply regulator pressures until they are
	fluid supplies could be unbalanced.	about equal. If the pressures are
		already about equal, verify that com-
		ponent A and B dose valves are oper-
		ating properly.
	Slow actuation of the component A or B	Manually operate the Dose Valve A
	valves. This can be caused by:	and B solenoid valves to check oper-
		ation.
	• Air pressure to the valve actuators is	• Increase air pressure. Air pres-
	too low.	sure must be 75-120 psi
		(0.52-0.84 MPa, 5.2-8.4 bar); 120
		psi is recommended.
	• Something is restricting the solenoid or	• There may be dirt or moisture in
	tubing and interrupting valve actuation	the air supply. Filter appropri-
	air.	ately.
	• Dose Valve B is turned in too far.	• Refer to Valve Settings, page
	Dose Valve A is open too far.	35, for adjustment guidelines.
	• Fluid pressure is high and air pressure	• Adjust air and fluid pressure. See
	is low.	recommended air pressure
		above.
QDA1	Valve seal or needle/seat are leaking.	Repair the valve.
Overdose A
	Slow actuation of component A or B valves.	See Ratio Low Error and Ratio High
The A dose has overshot and,		Error, pages 56-57.
when combined with B, is too
	Running a high mix ratio and a high flow	It may be necessary to restrict the
large for the mix manifold
	rate.	flow rate through the component B
capacity.
		dose valve by adjusting its hex nut.
QDB1
Overdose B
The B dose has overshot,
forcing an A dose that, when
combined with B, is too large
for the mix manifold capacity.

3A0868G 57