Series
PF2A/PF2W
Specific Product Precautions 1
Be sure to read before handling.
Design and Selection
Warning
Mounting
Thread
Rc 1/8
Rc 1/4
Rc 3/8
Rc 1/2
Tightening torque N
⋅
m
7 to 9
12 to 14
22 to 24
28 to 30
1. Mount switches using the proper tightening
torque.
When a switch is tightened beyond the specified tightening
torque, the switch may be damaged. On the other hand,
tightening below the specified tightening torque may cause
the installation screws to come loose during operation.
2. Apply wrench only to the metal part of the
pipings when installing the flow switch onto
the system piping.
Do not apply wrench to anything other than the piping
attachment as this may damage the switch.
3. Monitor the flow direction of the fluid.
Install and connect piping so that fluid flows in the direction
of the arrow indicated on the body.
4. Remove dirt and dust from inside the piping
using an air blower before connecting piping
to the switch.
5. Do not drop or bump.
Do not drop, bump, or apply excessive impacts (490 m/s
2
)
while handling. Although the external body of the switch
(switch case) may not be damaged, the inside of the switch
could be damaged and cause a malfunction.
6. Hold the body of the switch when handling.
The tensile strength of the cord is 49N. Applying a greater
pulling force on it can cause a malfunction. When handling,
hold the body of the switch – do not dangle it from the cord.
7.
Do not use until you can verify that
equipment can operate properly.
Following mounting, repair, or retrofit, verify correct
mounting by conducting suitable function and leakage tests
after piping and power connections have been made.
8. Avoid the mounting orientation with the
bottom of the body facing up.
The switch can be mounted in any way such as vertically or
horizontally, however, avoid the mounting orientation with the
bracket on the bottom of the body facing upward.
1. Operate the switch only within the specified
voltage.
Use of the switch outside the range of the specified voltage
can cause not only malfunction and damage of the switch but
also electrocution and fire.
2. Do not exceed the maximum allowable load
specification.
A load exceeding the maximum load specification can cause
damage to the switch.
3. Do not use a load that generates surge
voltage.
Although surge protection is installed in the circuit at the
output side of the switch, damage may still occur if a surge is
applied repeatedly. When a surge generating a load such as a
relay or solenoid is directly driven, use a type of switch with a
built-in surge absorbing element.
4. Since the type of fluid varies depending on the
product, be sure to verify the specifications.
The switches do not have an explosion proof rating. To prevent
a possible fire hazard, do not use with flammable gases or
fluids.
5. Monitor the internal voltage drop of the switch.
When operating below a specified voltage, it is possible that
the load may be ineffective even though the pressure switch
function is normal. Therefore, the formula below should be
satisfied after confirming the minimum operating voltage of the
load.
[For air]
6. Use the switch within the specified flow rate
measurement and operating pressure.
Operating beyond the specified flow rate and operating
pressure can damage the switch.
[For water]
7. Use the switch within the specified flow rate
measurement and operating pressure.
Operating beyond the specified flow rate and operating
pressure can damage the switch. Avoid especially the
application of pressure above specifications through a water
hammer.
<Examples of pressure reduction measures>
a) Use a device such as a water hammer relief valve to slow
the valve’s closing speed.
b) Absorb impact pressure by using an accumulator or elastic
piping material such as a rubber hose.
c) Keep the piping length as short as possible.
8. Design the system so that the fluid always fills
the detection passage.
Especially for vertical mounting, introduce the fluid from the
bottom to the top.
9. Operate at a flow rate within the flow rate
measurement range.
If operated outside of the flow rate measurement range, the
Karman vortex will not be generated and normal
measurement will not be possible.
Warning
Caution
Design and Selection
1. Data of the flow switch will be stored even
after the power is turned off.
Input data will be stored in EEPROM so that the data will not
be lost after the flow switch is turned off. (Data can be
rewritten for up to one million times, and data will be stored
for up to 20 years.)
[Series PF2A7
H]
10. Sudden increase of flow rate may destroy the
flow sensor. Ensure to open/close the flow
control valve not to exceed the maximum flow
rate measurement values.
Thread
Rc 3/4
Rc 1
Rc 1 1/2
Rc 2
Tightening torque N
⋅
m
28 to 30
36 to 38
48 to 50
48 to 50
Supply
voltage
– >
Internal voltage
drop of switch
Minimum operating
voltage of load
16-11-32
