cashco 764P Nstallation, Operation & Maintenance Manual

ISO Registered Company
I. DESCRIPTION AND SCOPE
The Model 764P is a pressure controller used for sensing static pressure, and outputting a pneumatic signal
pro por tion al to the deviation from the setpoint.
The Model 764PD is a differential pressure controller used for sensing two static pressures ("HIGH" and "LOW"),
and outputting a pneumatic signal proportional to the deviation from the setpoint.
With proper materials selection, the units are suitable for gaseous, liquid or steam service. Refer to Tech ni cal Bulletin
764P-TB for design con di tions and selection rec om men da tions.
Use of oxygen gas as the IAS for a 764P or 764PD is outside the scope of this IOM, and is considered "special
construction".
Abbreviations Utilized:
CCW – Counter Clockwise
CW – Clockwise
DIR – Direct
EXH – Exhaust
IAS – Instrument Air Supply
II. INSTALLATION
1. A block valve of the globe/needle type should
be installed at the location of the pressure
tapping. Ball, butterfly or gate valves are not
rec om mend ed.
2. Recommended sensing tap pipe size is 1/2"
(DN15).
3. Location of pressure sensing tap should be
in a zone not subject to flow disturbances.
Rec om mend a min i mum of 10 pipe diameters
upstream and 10 pipe diameters down stream
from any elbow, tee, valve, etc. that disturbs flow.
4. A pressure gauge is recommended at the location
of each tapping. Differential pressure designs
may in cor po rate a differential pressure gauge.
5. A pigtail siphon is required for hot condensing
fluids, such as steam, to assure a liquid trap at
the controller. The siphon should be installed
as near to the pressure connection(s) on the
controller's diaphragm hous ing as practical.
INSTALLATION, OPERATION & MAINTENANCE MANUAL (IOM)
MODEL 764P & 764PD
PNEUMATIC PRESSURE CONTROLLERS
SECTION I
P1 – Inlet Pressure
P2 – Outlet Pressure
PB – Proportional Band
PC – Pressure Controller
PCV – Pres sure Control Valve
PI – Pres sure Indicator
SECTION II
P/P –
REV – Rev o lu tion or Re verse
SIG –
SRV – Safe ty Relief Valve
TR –
V –
IAS @
60-100
Airset
psig
Supply
Port "B"
MODEL
764P
PC
Port "A"
Supply @
P1
EXH
SIG
LOAD
Supply
TR
Blowdown - Drain
(Shaded portion for steam/condensate systems)
Figure 1: Recommended Piping Schematic for Pres sure
Reducing Control Valve with Positioner
IOM-764P / PD
Pneu mat ic-to-Pneu mat ic
Sig nal
Con den sate Trap
Vent
SRV
PI
Pigtail
Siphon
REV
PROCESS
"Output"
PCV
P/P
DIR
Bypass
V
TR
Blowdown - Drain
02-20
Outlet
@ P2