Graco ProMix 2KE Operation page 49

Alarm and Description
R4
Ratio High
The mix ratio is higher than
the set tolerance for an A to B
component volume compari-
son.
QDA1
Overdose A
The A dose has overshot and,
when combined with B, is too
large for the mix manifold
capacity.
QDB1
Overdose B
The B dose has overshot, forc-
ing an A dose that, when com-
bined with B, is too large for
the mix manifold capacity.
3A0868A
Cause
There is too little restriction in the system. •
If the alarm occurs during start up, after
purging, the flow rate was probably too
high.
If the alarm occurred after you were
spraying for some time, the pressures
from the fluid supplies could be unbal-
anced.
Slow actuation of the component A or B
valves. This can be caused by:
• Air pressure to the valve actuators is
too low.
• Something is restricting the solenoid
or tubing and interrupting valve actua-
tion air.
• Dose Valve B is turned in too far.
Dose Valve A is open too far.
• Fluid pressure is high and air pres-
sure is low.
Valve seal or needle/seat are leaking.
Slow actuation of component A or B
valves.
Running a high mix ratio and a high flow
rate.
Solution
Check that the system is fully
loaded with material.
• Check that the supply pump's cycle
rate is set properly.
• Check that the spray tip/nozzle is
properly sized for the flow and appli-
cation, and that it is not worn.
• Check that the fluid regulator is set
properly.
Restrict gun needle travel to slow down
the initial fluid delivery rate until fluid
hoses are loaded with material.
Adjust component A and B fluid supply
regulator pressures until they are about
equal. If the pressures are already
about equal, verify that component A
and B dose valves are operating prop-
erly.
Manually operate the Dispense A and B
solenoid valves to check operation.
• Increase air pressure. Air pressure
must be 75-120 psi (0.52-0.84 MPa,
5.2-8.4 bar); 120 psi is recom-
mended.
• There may be dirt or moisture in the
air supply. Filter appropriately.
• Refer to Valve Settings, page 28,
for adjustment guidelines.
• Adjust air and fluid pressure. See
recommended air pressure above.
Repair the valve.
See Ratio Low Error and Ratio High
Error, pages 48-49.
It may be necessary to restrict the flow
rate through the component B dose
valve by adjusting its hex nut.
System Errors
49