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6 Installation
S
ection 2: Installation 389VP Instruction Manual
January 2013 PN 51-389VP
Submersion Mounting
The 389 and 389VP Sensor has a 1 in. MNPT process connection at the back of the sensor. Utilizing
a standard 1 in. union, the sensor may be mounted to a 1 in. SCH 80 CPVC or PVDF standpipe.
Tapered pipe threads in plastic tend to loosen after installation. It is therefore recom mended that
Teflon1 tape be used on the threads and that the tightness of the connection be checked fre-
quently to assure that no loosening has occurred. To prevent rain water or condensation from run-
ning into the sensor, a weatherproof junction box is recommended (See Figure 2-2). The sensor
cable must be run through a protective conduit for isolation from electrical interference or physi-
cal abuse from the process. The sensor should be installed within 80° of vertical, with the electrode
facing down. The sensor’s cable should not be run with power or control wiring.
Flow Through and Insertion Mounting
The 389 and 389VP Sensor also has a 1 in. MNPT process connection at the front of the sensor for
mounting into a 1-1/4 in. tee or the process. See Figure 2-3 for instal lation configurations.
NOTE: LARGE PIPE WRENCHES MUST NOT BE USED TO TIGHTEN THE SENSOR INTO A FLANGE OR
OTHER TYPE OF MOUNTING.
Electrical Installation
Figures 2-5 thru 2-22 provide the guidelines for wiring the 389VP sensor to various
Analyzer/Transmitter instruments.
To determine which wiring guideline to use, locate the code number of the sensor to be installed.
This number is stamped in the body of the sensor.
1. If the cable needs to be extended, use a high quality four conductor shielded instrument cable
available from Rosemount Analytical.
NOTE: If the cable is too long, loop up the excess cable. If the cable has to be shortened, splice and
terminate each conductor neatly and make sure that the overall (outermost) drain wire is not
shorted out with either of the two inner drain wires (shields).
2. Signal cable should be run in a dedicated conduit (preferably an earth grounded metallic con-
duit) and should be kept away from AC power lines. For your convenience, a spade lug kit is fur-
nished (in a plastic bag wrapped around the cable).
2.2.1
2.2.2
2.3