Leslie Controls CONTROL VALVES SINGLE PORTED DOS - Manual (Page 4)

4
diaphragm. Rated travel is shown by
position of travel indicator on valve
stem relative to travel indicator scale on
yoke.
3.
Manually operate control valves fitted
with manual operating devices through
rated travel to check freedom of
movement.
4.
Place control valve in operation in
accordance with instructions furnished
with control pilot or other operating
device.
MAINTENANCE
(DL, DDL, DOS, DDOS – 600 lbs. or
less)
NOTE: To reduce maintenance time refer to
proper drawing and follow steps shown below
for applicable maintenance operation.
To Renew Valve Plug
Stem Packing
Maintenance
To dismantle Control
Valve – Inspect Parts –
Replace or Regrind
Valve
Plug/Seat
Ring(s)
Maintenance -
Dismantling
To Reassemble
Control Valve
Maintenance –
Reassembly
To Preload Adjusting
Spring
Set Rated
Travel
Maintenance –
Reassembly 3 thru 10
To Replace Diaphragm
and/or Stem Seal Actuator Maintenance
To change Valve
Action Normally Open
to Normally Closed or
Vice Versa
Actuator Maintenance
Replacing Valve plug Stem
Packing
Replace valve plug stem packing if control valve
has been in service beyond normal maintenance
and packing shows signs of wear. Wear will be
indicated by leakage, which cannot be corrected
by minor tightening of packing flange.
Where Leslie BRAIDED TEFLON GRAPHITE
packing is in use, additional packing rings can be
installed to overcome minor leakage without
dismantling the control valve or breaking valve
plug connection.
Dismantling
1.
Close inlet and outlet stop valves. Operate
system on bypass, if necessary.
2.
Shut off operating medium and relieve
pressure from diaphragm by disconnecting
tubing at diaphragm case.
To Install a Complete Set of
Packing
1.
Disassemble control valve as far as
necessary for work required. Remove old
packing. Clean valve plug stem and packing
box thoroughly. Polish valve plug stem with
crocus cloth. Use approved, non-residue
forming solvent for cleaning. Wipe dry with
clean cloth.
2.
Insert a new set of packing in packing box in
the order shown on the packing wrapper.
Packing
wrapper contains complete
installation instructions on how to install a
set of packing. Each wrapper shows the
order in which the various pieces of packing
are to be inserted in the particular valve in
which they are to be used.
3.
After packing is installed, reassemble
packing follower, packing box flange and
bolts/studs to bonnet. Tighten bolts/studs as
shown in instruction on wrapper.
WARNING
Injury or death can occur due to failure to
completely isolate valve from all sources of
pressure before beginning disassembly. Do not
proceed until valve has been completely isolated
from the process and vented to atmosphere.