Leslie Controls CONTROL VALVES DLOS-2 & DDLOS-2 (150/300) - Manual (Page 8)

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close tightly and will not begin to open until
the 3 PSIG operation pressure is exceeded.
NOTE A: A control valve which has been
adjusted to provide 3 PSIG starting pressure
plus valve closure force (with pressure in body)
will have a considerably higher start-pressure
than 3 PSIG, when tested at 0 body pressure.
NOTE B: Air pressures quoted are relative.
Actual pressures required in operation may vary
with pressure drop conditions existing and/or
actuator springs used.
6.
Loosen lock nut. Apply air to diaphragm.
Turn valve plug stem into upper stem
threads until valve plug is out of contact
with seat ring, when air is removed from
diaphragm. Then turn valve plug stem out
of coupling threads until valve plug just
contacts seat ring again.
7.
Supply sufficient operating pressure to
actuator diaphragm to move valve plug
away from seat ring. Then turn valve plug
stem one full turn out of actuator upper stem
threads. Diaphragm disc determines travel.
With proper diaphragm disc correct travel
will result from adjustment.
8.
OVERTRAVEL – If travel is too great,
loosen and turn valve plug stem out of upper
stem (35) and the amount necessary to
obtain correct travel.
9.
UNDERTRAVEL – If travel is too short,
loosen lock nut and turn valve plug stem
further into upper stem (35) the amount
necessary to obtain correct travel.
10.
When correct travel has been obtained
increase operating pressure sufficiently to
move valve plug away from seat ring. Then
turn valve plug stem one full turn out of
upper stem threads.
11.
The one full turn toward the seat ring, 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.
12.
Tighten locknut. Reconnect operating
medium tubing from the sensing element or
manual loading device to the diaphragm
case.
DISASSEMBLY
REPLACING DIAPHRAGM, STEM SEALS,
ETC.
(See Fig. 7 and 9 in Appendix)
1.
Shut inlet and outlet stop valves for fluid
supply lines and air supply to actuator
connection.
2.
Disconnect tubing at diaphragm case
connection.
3.
Remove compression on spring by turning
spring adjustor until spring is free. See label
on yoke for proper directions of rotation.
REPLACING
DIAPHRAGM DIRECT
ACTING ACTUATOR ONLY
(See Fig. 7 in Appendix)
Follow steps 1 to 3
4.
Remove diaphragm case nuts and bolts,
diaphragm case upper and diaphragm.
5.
Replace diaphragm with a new one then
reposition diaphragm case upper bolts and
nuts. Tighten all nuts.
REPLACING
DIAPHRAGM AND/OR
STEM SEALS REVERSE ACTING
ACTUATOR
(See Fig. 9 in Appendix)
6.
Insert a lock rod through hole in the yoke
and into hole in actuator stem. (Secure
actuator stem with wrench if stem has no
hole.)
7.
Dismantle upper diaphragm case and Hand
Operating Device (if so fitted) from actuator
as described in instructions.
8.
Remove the lock nut (16), diaphragm disc
(17), diaphragm (20) and collar (22).
9.
35R – Remove 8 cap screws from lower
diaphragm case, lift off case and remove
stem seal.
55R & 85R – Take out screws from seal
ring. Remove seal ring, stem seal, and stem
collar.