Leslie Controls CONTROL VALVES SINGLE PORTED DOS - Manual (Page 9)

9
plug away from seat ring/insert(s). Then turn
valve plug stem one full turn out of actuator stem
threads until valve plug just contacts seat
ring/insert again.
Single Ported Unbalanced
Control Valves (DDL, DDOS
Types)
(With Reverse Acting Actuators)
Loosen stem locknut, apply air to diaphragm.
Turn valve plug stem into actuator stem threads
until valve plug is out of contact with seat ring,
with air removed from diaphragm. Then turn
valve plug stem out of actuator stem threads until
valve plug just contacts seat ring again.
Supply sufficient operating pressure to actuator
diaphragm to move valve plug away from seat
ring/insert. Then turn valve plug stem one full
turn out of actuator stem threads. Diaphragm
plate determines travel. With proper diaphragm
plate correct travel will result from adjustment.
For under or overtravel, proceed as described
above.
Positive Closing Force
The one full turn toward the seat ring/insert
made after obtaining travel, provides the positive
closing force required to obtain tight valve
closure in single ported valves. In all cases be
sure to make this final adjustment.
All Actuators
Tighten stem locknut and travel indicator against
actuator stem. Reconnect operating medium
tubing from the sensing element or manual
loading device to the diaphragm case.
ACTUATOR MAINTENANCE
REPLACING DIAPHRAGMS,
STEM SEALS, ETC.
Remove compression on actuator spring by
screwing
adjuster counterclockwise until
actuator spring is free.
Dismantling
– SIZES 35, 55, 85, 135
(See Fig. 8)
Direct Acting
(See Page 9, Valve Action)
Remove bolts/nuts (23/22), upper diaphragm
case (20) and old diaphragm (21).
To examine, clean or replace other internal
components lift off diaphragm plate (24)
assembled with actuator stem (31), actuator
spring (28), washer (34) and unscrew spring
adjuster from adjuster sleeve (36).
Reassembly
Replace internal parts. Install new diaphragm.
For sizes 35, 55 and 85 line up holes with those
in lower diaphragm case. For size 135 place
bead on diaphragm in recess in lower diaphragm
case. Place upper diaphragm case on diaphragm.
Assemble four bolts and nuts through parts (90
°
apart). Finger tighten. Assemble balance of
bolts/nuts to actuator. Tighten evenly and
alternately across diaphragm case. (Before
tightening bolts in 35R actuator or where flat
diaphragm material is being used as an
emergency measure) consult note relating to
preforming diaphragms.
Reverse Acting
(See Page 9, Valve Action)
Remove bolts/nuts (19/18) and upper diaphragm
case (15). Insert rod through holes in yoke (34)
and actuator stem (35) to prevent twisting of
stem seal (29) when removing self-locking nut
(16). (For size 35R use wrench flats on actuator
stem). Remove self-locking nut (16), diaphragm
plate (17), diaphragm (20), collar (22) and stem
seal (29). Remove stem seal as follows: (Before
tightening bolts in 35R Actuator or where flat
diaphragm material is being used as an
emergency measure). In 135R remove capscrews
(23) in 35R and disassemble lower diaphragm
base (21) from yoke (34). Lift out stem seal. In
55R and 85R DO NOT remove lower diaphragm
base unless gasket (26) needs to be replaced.
Stem seal (29) is held in place by seal ring (27)
and screws (28). Remove these parts and lift out
stem seal.