9
Model 351/352/353 Liquid Level Systems
Section 3
Section 3—Installation
Unpacking
All instruments are inspected during manufacture and prior to shipping. How-
ever, an inspection should be performed at the time of unpacking to detect
any damage that may have occurred during shipping.
When unpacking, carefully remove the instrument from the container. If the
instrument is a liquid-filled sys tem, remove the strap-fasteners and gently
unroll
the capillary tubing.
The transmitter output may indicate “Near Full Scale” if the system is tested
prior to installation. This is nor mal, and the transmitter output will be correct
when the reference leg is elevated.
Model 353 Sensor Assembly
The Model 353 sensor bellows and bottom plate bolts are not torqued to
installation requirements as shipped. See
for instruc-
tions on removal and replacement of Model 353 sensor bellows.
Mounting
Mount the sensors as close to vertical orientation as possible to ensure proper
operation. The sensor may be oriented with the vent pointed up or down,
depending on the service or installation design.
When mounted with the L-bracket, mount the sensors with three 3/8-16 SAE
bolts, Grade 5
or better, torqued to 24 to 26 ft-lb (33-35
N-m). The mount-
ing bracket may be rotated axially or reversed, as required for installation (as
shown in dimensional drawings in Section 6).
Interfacing process tubing should be supported to minimize relative motion
between the sensor and connections. The capillary tubing should be supported
with at least one support located within 1 ft (0.3 meters) of the sensor. The
minimum bend radius of the capillary tubing is 2 in. (50
mm).
Piping and Installation
IMPORTANT: Sealed systems are normally filled at the factory, but can be installed and
filled in the field.
Sensors should be connected in accordance with user specifications. Flanges
and tube fittings (3/8”, 1/2” or 3/4”) are available for this purpose.
