Leslie Controls DKLO D1 & D4 .5-4 125/250 class - Manual (Page 4)

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OPERATING PRINCIPLE
The Dklo D1 & D4 Valves are flow to open, globe style,
pneumatic diaphragm control valves. The pneumatic
actuator can be arranged to operate with either air to open
control. A controller sensing the controlled variable
provides a signal to the actuator of the control valve to
obtain the desired control. See application guide for other
operating instructions.
service is recommended. To eliminate excessive noise with
steam and other compressible fluids, enlarge the delivery
pipe size to effect a reasonable flow velocity at the reduced
pressure. A concentric transition is recommended. If
possible, avoid sharp turns close to the valve bullheaded
tee connections to a low pressure main. Install initial and
delivery pressure gauges to indicate performance. If the
rating of the delivery system or connected equipment is
less than the initial pressure, provide a safety relief valve.
START-UP
Flush piping system thoroughly to clear it of welding
beads, scale, sand, etc. Install valve with the arrow on the
side of the valve body pointing in the direction of fluid
flow. Install controller and accessories in accordance with
instructions furnished by the manufacturer of these items.
Connect necessary airlines and/or electrical connections
INSTALLATION
Locate the valve in a straight run of horizontal pipe as
shown in Figure 1. The valve should be mounted with the
actuator in the upright position. Allow room for removal of
the actuator. Prevent pipeline hammering in compressible
fluid service by providing proper drainage before and after
the valve. Avoid damaging effects of scale and dirt in
pipelines by using a strainer. A 3-valve by-pass to
facilitate inspection and maintenance without interrupting
to diaphragm chamber and valve mounted accessories. Use
1/4" O.D. tubing for all air lines. If length of the air line
exceeds 25 ft, use 3/8” O.D. tubing. Insulation, if desired,
may be applied to the valve body only. Do not insulate
bonnet. Caution: Hazardous fluids may be handled by this
valve. Only qualified personnel, who are familiar with
your installation, should be permitted to install, readjust,
inspect or maintain the valve.
TROUBLESHOOTING
For troubleshooting of the controlling device and
accessories, see instruction furnished by manufacturer of
these items. To troubleshoot valve and actuator, check for
the following: change in operating conditions; pneumatic
signal failure; diaphragm failure; foreign matter lodged
between seat ring and plug; actuator vent plug may be:
plugged, missing, replaced with a solid plug; packing
leakage.
Figure 1 – Typical Steam Installation