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3.2 Installation
3.2.1
171 & 172 Series regulators must be installed with the
actuator 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
downwards 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 components
of the regulator.
Fig.6
1) Adjustment screw
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 case
is not normally airtight (ATEX construction, Group II- Cat.2),
and has a hole (5) in Fig.6 and 7 which prevents it from pres-
surizing if the diaphragm breaks. If the spring case 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).
Instructions
EY0171-0172 – 10/08
171 and 172 Series
Self-Operating Pressure Regulators
This pipe shall be linked to
ATEX form (Gr. II Cat. 2)
only in case of non high-
explosive atmosphere
Fig.8
Pressure reduction system
: 1) Reducing regulator –
2) safety relief valve – 3) pressure gauge
3.2.4
Please keep 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
calculating 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. 9. The 1/8" female threaded
port must be connected to a nipple as near as possible to the
point of use.
3.2.6
If you are not sure that the regulated fluid is clean, install
a filter before the regulator.
Fig.9
External sensing line nipple (only on request)
3.3 Start-Up and Calibration
3.3.1
The 171 and 172 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 turn-
ing the adjusting screw (15) clockwise to increase the pressure
setting or counterclockwise to decrease the pressure setting.
DV-215-171_172 series Inst-v13.indd 4
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