Setra System Model 231 - Manual (Page 5)

5
2.3 Pressure Fittings
Typically standard pipe fittings and installation procedures should be used.
The Model 231 has 1/8”
−
NPTF internal fittings. The high pressure port and low
pressure port are located on the bottom of the unit , labeled “HI” and “LO”, respec-
tively. The optional 3-valve manifold assembly is supplied with 1/4”–18 NPT
internal fittings.
Moisture Precautions
The Model 231 is provided with a 0.875 DIA. conduit opening for electrical
termination, intended for a 1/2” I.D. conduit connection. This opening must be
sealed according to standard industry practices in order to prevent moisture
ingress into the Model 231.
2.4 Mounting
The Model 231 can be easily mounted using the two mounting screws located
on the side of the unit.
2.5 Installation Procedures
If the Model 231 is supplied with an optional 3-valve Manifold assembly, refer to
section 3.0, Optional 3-Valve Manifold Assembly Procedure, for further installation
procedures. If the Model 231 is not supplied with a Setra 3-Valve manifold, the
following installation procedure is recommended.
For differential pressure measurements at high line pressure, it is recommended
that the pressure sensor be installed with a valve in each line, plus a shunt valve
across the high and low (reference) pressure ports as shown.
Important: Do not exceed maximum range pressure with the total of
differential pressure and line pressure.
Valve 1 = High Side Valve
Valve B = Low Side Valve
Valve C = Shunt Valve
High
Valve A Valve B
Valve C
Low
High Low
Differential
Pressure Sensor
Figure 1