Graco 3A0869H - page 63

System Errors
3A0869H 63
QDA1, QDA2, QDA3
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,
forcing an A dose that, when
combined with B, is too large
for the mix manifold capacity.
Valve seal or needle/seat are leaking. Repair the valve.
Flow meter fluctuations caused by pres-
sure pulsations.
Check for pressure pulsations:
1. Close all the manifold valves.
2. Turn on the circulating pumps and
all the booth equipment (such as
fans and conveyors).
3. Check if the ProMix 2KE is reading
any fluid flow.
4. If the ProMix 2KE shows there is
fluid flow and there are no leaks
from the gun or any other seals or
fittings, the flow meters are proba-
bly being affected by pressure pul-
sations.
5. Close the fluid shutoff valve
between the fluid supply system
and the flow meter. The flow indica-
tion should stop.
6. If necessary, install pressure regu-
lators or a surge tank on the fluid
inlets to the ProMix 2KE to reduce
the fluid supply pressure. Contact
your Graco distributor for informa-
tion.
Slow actuation of component A or B
valves.
See Ratio Low Error and Ratio High
Error, pages 61-62.
Running a high mix ratio and a high flow
rate.
It may be necessary to restrict the flow
rate through the component B dose
valve by adjusting its hex nut.
Alarm and Description Cause Solution