Leslie Controls Pilot Controller - Manual (Page 8)

Page 8
Figure 12. — Pilot Controller piping details — Typical installation
STOP — LOOK — READ OBSOLETE
ADHERENCE TO THESE INSTRUCTIONS
GUARANTEE OPTIMUM RESULTS
INSIST UPON THEIR BEING FOLLOWED.
SECTION I — INSTALLATION
Install Pilot Controller vertically in an accessible location.
Allow removal¬ space for ease of maintenance. Pilot
Controller may be located above or below line controlled.
NOTE: Whenever hydrostatic head exists on diaphragm effect
must be considered with relation to obtainable pressures.
Piping Details
Figure 1 shows control pilot piping details. Control valve pip-
ing shown in figures is schematic only. Consult Control Valve
Instructions for piping details.
Control Pipe Connection and Length
Connect Control Pipe from top of diaphragm cover to con-
trolled pressure line. Make connection in controlled pressure
line at least 3 feet from the valve body opening or the end of
the expander, if one is in use. Best results are obtained when
length of control pipe does not exceed 30 feet. Avoid con-
nections near turbulent areas such as those created by ori-
fices, elbows, sharp bends, or other flow direction changing
components.
Pitch or Slope of Control Pipe
Pilot Above Line Controlled — Slope control pipe downward,
away from the Pilot Controller. Provide at least 6" of vertical
pipe at connection to pilot cover.
Pilot Below Line Controlled — Slope control pipe downward
toward Pilot Controller.
Hydrostatic Head Pressure
Where the Pilot Controller is to be installed under the line con-
trolled (and liquids or condensible gases are to be controlled)
total pressure resulting from hydrostatic head and controlled
pressure must not exceed the maximum range of the control
pilot.
AIR LINES — Use 5/16" (1/4"
I.D.) pipe or tubing. Use non-
corrosive pipe and fittings.
6" Vertical Section (Min.)
Connect outlet of air reducing valve to
inlet of Pilot Controller (immediately
under gage marked “Operating
Supply”). Connect outlet of Pilot
Controller (immediately under gage
marked “Control Valve”) to diaphragm
connection of Control Valve.
Union
AVOID LOOPS OR POCKETS IN
CONTROL PIPES to insure true
pressure signal to pilot diaphragm.
Control pipe — use 1/2" 40 sched-
ule pipe or tubing with equivalent
internal diameter
(For ranges up to and including
50-125 psig: for ranges 100-200
psig and over use 3/8" pipe).
Stop Valve
*See NOTE
Gage
Operating medium clean air** Set
Reducing Valve to supply 20-22 psig
to pilot.
*NOTE: AIR CONNECTIONS — Pilot Controller is equipped
with stainless steel air supply and output fittings. DO NOT
remove. Connect air lines directly to these fittings. **NOTE: Operating medium for Classes PRA-1, PDA-1,
UDRV, UDDV etc. (aluminum construction) must be
clean air. (Win Class designation) are suitable for oil or
water as operating medium.
Strainer
*Use with Instruction 20/2.5.3 for replacing upper diaphragms — UDDV, UDRV Types.
**Use instruction 20/3.5.1 for replacing upper diaphragms — DDD, UDDD Types.
Types Covered:
PDA-1 PDW-1 PDQ-1 UDDV* DDD**
PRA-1 PRW-1 PRQ-1 UDRV* UDDD***
CONSTANT, DIFFERENTIAL PRESSURE AND RATIO
PILOT CONTROLLERS
Force Balance, Fixed Band Types