QVE1901U Flow Switch
Technical Instructions
Document Number 155-711
September 20, 2012
Siemens Industry, Inc.
Page 3
Engineering Notes
•
On
site:
–
A T-junction with a female-threaded (1/2" NPT) fitting is required for 3/4” to 2”
line sizes.
–
A 1-inch, female-threaded (1/2” NPT) welding socket is required for 3" to 8" line
sizes.
•
All dimensions and data provided in the table of switching values are based on water
at 68°F (20°C), and the use of T-junctions and
horizontal
piping.
Flow Switch
Installation
•
When choosing the installation site, ensure that the specified limit values (see
Technical Data
) are not exceeded.
•
Select suitable measures to prevent the medium from freezing. If the flow switch is to
be used in ambient temperatures of <39°F (4°C), do not carry out any operation
beforehand using pure water. Residual water in the flow switch can result in frost
damage.
Mechanical installation
General installation
instructions
•
First, clean the pipe system where the flow switch is installed and remove any
magnetic particles, such as welding residue.
•
The laminar path length in front of and behind the flow switch must be at least 10
times and 5 times the pipe diameter, respectively.
•
The nominal installation position of the flow switch is an upright standing position in
horizontal pipework.
•
The switches should only be installed in a vertical position with a maximum deviation
of 45°.
SEN0531R1
max.
45°
Figure 2. Acceptable Switch Mounting Positions.
•
Ensure that there are no external magnetic fields in the immediate vicinity of the flow
switch, since these can impair device operation.
•
There is an arrow on the flow switch. Install with the arrow parallel with the pipe
shaft, facing in the flow direction.
SEN0522R1
Figure 3. Flow Direction Arrow.
•
The brass connecting nut G¾ has a tightening torque of 18 to 22 lb-ft (25-30 Nm)
