Leslie Controls CONTROL VALVES SINGLE PORTED DOS - Manual (Page 11)

11
SOME IMPORTANT NOTES
FLAT SHEET RUBBER MATERIAL
Flat sheet rubber material may be used in 55R,
85R and 135R actuators as emergency
replacement material but for guaranteed results it
should be replaced at the earliest opportunity
with
the LESLIE ROLLING ACTION
DIAPHRAGM designed specifically for these
actuators. When flat material is used in
emergency preform as described below.
PREFORMING 35R ACTUATOR
DIAPHRAGMS
Flat stock material is used for diaphragms in 35R
actuators. When assembling, first finger tighten
all diaphragm case bolts. Then compress
actuator spring sufficiently to move diaphragm
through full travel to the upper or lower
diaphragm case (depending on whether actuator
is direct or reverse acting). This preforms
diaphragm and permits full movement through
rated travel without resistance from a taut
diaphragm.
To Change Valve Action from
Normally Open to Normally
Closed or Vice-Versa
To reverse the action of a single ported
diaphragm control valve it is only necessary to
replace the actuator in use with one having the
opposite action. A single “D” in the control
valve class indicates actuator is “DIRECT
ACTING” - Air moves diaphragm downward.
A double D (“DD”) indicates actuator is
“REVERSE ACTING” - Air moves diaphragm
upward. NOTE: Final valve action in response
to air signal on diaphragm depends on whether
valve plug is positioned above or below the seat
ring.
To change actuator, loosen valve plug stem
locknut under travel indicator and turn valve
plug stem all the way out of the actuator stem.
Remove capscrews securing actuator to bonnet.
Replace actuator with one having desired action.
Re-insert and tighten capscrews. Reconnect
valve plug stem to actuator stem. Adjust
actuator spring preload and set valve for rated
travel. For more detailed instruction consult
general instruction pertaining to the particular
type of control valve.