Spray Pattern Adjustment
311320K
15
5. Fine tune spray pattern:
a. After you back out adjustment screw, make fine
adjustments (1/8 turns or less in either direction
as required) to obtain pattern shown in . Moving
the screw out beyond this point may cause the
pattern to split, as shown in F
b. If full-round pattern cannot be achieved, ensure
that material temperature and spray pressure
are correct. If pattern remains closed upon
reaching maximum specified number of turns
out from point of valving, material temperature
is too low
c. If pattern splits or has hollow center, even with
the adjustment screw at minimum number of
turns from point of valving, material temperature
is too high. Refer to F
d. After reaching satisfactory spray pattern, note
temperatures at proportioner and hose, and
position of notch on the adjustment screw. As
spraying proceeds, pattern may occasionally
streak or change. If this happens, inspect
chamber tip and remove any build-up of solid
foam with wooden stick or brass wire brush.
e. If buildup recurs shortly after cleaning tip,
remove air cap and ensure inside is clean.
Reinstall air cap and ensure airflow is properly set.
If no buildup occurred on air cap, check the following
items in this order and readjust if necessary:
•
Check Valving Rod Adjustment Screw/Sleeve
setting.
•
Check hose temperature setting.
•
Check primary heater temperature setting.
•
Ensure spray pressures between chemicals are
balanced. If they are not, refer to Troubleshooting
section of Proportioning Unit Operation Manual for
the proportioner in use.
•
Ensure flow of air to air cap is adequate but not
excessive.
Table 1: Valving Rod Adjustment for Standard Mixing Chambers
F
IG
. 13 Desired Pattern
F
IG
. 14 Split Pattern
Chamber
Turns Out From Point of Valving Recommended Distance of Gun
from Surface
Pattern Size
Minimum
Maximum
46-800
1/2 turn
2 turns
12 in. (304-8 mm)
6 in. (152.4 mm)
46-810
1/2 turn
2 turns
12 in. (304-8 mm)
6 in. (152.4 mm)
55-776
1 3/4 turns
2 5/8 turns
18 to 20 in. (457.2 to 508 mm)
8 in. (203.2 to 228.6 mm)
62
2 turns
3 turns
18 to 20 in. (457.2 to 508 mm)
8 to 9 in. (203.2 to 228.6 mm)
70
2 turns
3 turns
18 to 20 in. (457.2 to 508 mm)
10 to 12 in. (254 to 304.8 mm)
78-851
2 turns
3 turns
24 in. (609.6 mm)
14 in. (355.6 mm)
