4
3.2.4
Please bear in mind that the regulated pressure sens-
ing port is located inside the regulator, therefore the pressure
drops in the inter-connecting piping between the regulator and
the point of use will affect the accuracy of the maintained set
pressure. This pressure drop must be considered when calcu-
lating the size of the connection piping.
3.2.5
When it is essential to avoid pressure variations at the
point of use, the regulators are fitted with an external sensing
line connection, as shown in Fig 8. The 1/8" female threaded
port must be connected to a nipple as near as possible to the
point of use.
Fig.8
External sensing line (only on request)
3.3 Start-Up and Calibration
3.3.1
The 173 series pressure regulators are shipped with a
pressure setting at the low end of the adjustable range unless
otherwise specified by the customer. The pressure setting
can be changed to any value within the adjustable range by
loosening the adjusting screw locknut (14) and turning the
adjusting screw (13) clockwise to increase the pressure set-
ting or counterclockwise to decrease the pressure setting.
During regulator start-up or operation, do not touch any part
of the regulator as this can conduct heat if the fluid used is at
a high temperature.
3.2 Installation
3.2.1
173 Series regulators must be installed with the actuator
(2) facing upwards and the diaphragm perfectly horizontal, as
shown in Fig.6.
In pressure reducing applications regulating very low down-
stream pressures (normally lower than 100 mm water column);
the regulator must be installed with the actuator facing down-
wards and perfectly horizontal (below pipeline) as indicated by
the nameplate orientation as shown in Fig. 7.
3.2.2
Before installation, ensure piping is clean, free of any
debris (machining chips, weld slag, etc). Contaminants
remaining in the piping system can damage internal compo-
nents of the regulator.
Fig.6
1) Adjustment screw (spring holder)
2) Actuator
3) Pressure gauge
4) Regulator body
5) Drain hole
Fig.7
3.2.3 WARNING/CAUTION ON ATEX USAGE:
When handling/
working on harmless fluids (e.g. inert gases, like nitrogen,
carbon dioxide and noble gases) the spring cover is not normally
airtight (ATEX construction, Group II- Cat.2), and has a hole
(5) in Fig.6 and 7 which prevents it from pressurizing if the
diaphragm breaks. If the spring cover is airtight (Fig.4), made
from carbon steel and stainless steel, the hole (5) in Fig.6 and
7 is always threaded ¼"NPT and must be connected to pipe
conveying the discharge to a suitable place (safely and
constantly at atmospheric pressure).
This pipe shall be linked to
ATEX form (Gr. II Cat. 2)
only in case of non high-
explosive atmosphere
Instructions
EY0173 – 10/08
173 Series
Self-Operating Pressure Regulators
DV-216-173 series Inst-fnl.indd 4
11/20/08 9:29:51 AM
