Datasheet
1.
Operate the switch only within the specified voltage.
Use of the switch outside of the specified voltage range can
cause not only a malfunction and damage to the switch, but it
can also cause electrical shock 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 a surge voltage.
Although the circuit at the output side of the switch is surge-
protected, damage may still occur if a voltage surge is applied
repeatedly. When a load which generates a surge, such as
from a relay or solenoid valve, is directly driven, use a 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 inflammable gases or fluids.
5.
Monitor the internal voltage drop of the switch.
When operating below the 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. Especially avoid the application of pressure
through a water hammer, which is above the specification.
<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 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.
[Series PF2A7H]
10.
Sudden increase in flow rate may destroy the flow
sensor. Ensure to open/close the flow control valve not
to exceed the maximum flow rate measurement values.
Warning
Design and Selection
Supply
voltage
– >
Internal voltage
drop of switch
Minimum operating
voltage of load
Design and Selection
38
Specific Product Precautions 1
Be sure to read before handling. Refer to page 37 for safety instructions.
Series PF2A/PF2W
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 the switch using the proper
tightening torque.
When the switch is tightened beyond the specified tightening
torque, it may be damaged. On the other hand, tightening
below the specified tightening torque may cause the
installation screws to loosen during operation.
2. Apply a wrench only to the metal part of the
piping when installing the flow switch onto
the system piping.
Do not apply the wrench to any part other than the piping
attachment or the switch may be damaged.
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 of the
piping by means of air blow, before
attaching 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 switch inside could be
damaged and cause a malfunction.
6. Hold the body of the switch when handling.
The tensile strength of the cord is 49N and applying a greater
pulling force than this can cause a malfunction. When
handling, hold the body of the switch.
7. Do not use until you can verify that equip-
ment 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.
Caution
1. Data from the flow switch is stored even
after the power supply is turned off.
The input data is stored in EEPROM so that the data will not be
lost after the flow switch is turned off. (The data can be rewritten
for up to one million times, and stored for up to 20 years.)
2. Accumulated flow rate is reset when it is
turned OFF.
Only the PF2A7H series (for air) will maintain, its
accumulated flow rate value, even though the power supply is
cut.
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