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Bypass Unit Replacement Guidelines
● Do not lift or carry the flow meter by holding the bypass unit. Doing
so can damage the flow meter or cause it to fall, creating the risk of
personal injury.
● When replacing the bypass unit, be sure to release flow meter
internal pressure before removing the current bypass unit.
● Replacing the bypass unit causes the ±3
%
FS ±1 digit
instantaneous flow rate display accuracy to become ±5
%
FS ±1
digit.
CAUTION
● The following modes support bypass unit replacement: FAS-030,
-060, and -120.
Mounting the bypass unit
1. Check to make sure that the rubber sheet of the new bypass
unit is securely affixed and that the gasket that was in place
when you purchased the unit is affixed to the main channel.
With the arrow on the label of the bypass unit aligned with the
arrow on the label of the main channel, mount the bypass
unit on the main channel with four bolts. Be sure to tighten
the bolts evenly to a tightening torque of 2. 6 to 3. 3 N
・
m.
2. Connect the cables and turn on power. Keep the tightening
torque of the cable nut to 0. 4 to 0. 6 N
・
m range.
3. From the basic screen, enter maintenance mode. Input
channel ID numbers for 0, 1, and 2, and input the model
number.
For details, see "●Maintenance Mode" on page 13.
If the new replacement bypass unit remains locked, normally
the setting lock of the channel ID numbers and model
number are disengaged, input 1111 for the P_Code
reservation code in the case.
・
The channel ID numbers are marked on the Body Number
label of the main channel.
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Body Number
Channel ID number 0
Channel ID number 1
Channel ID number 2
・
Model numbers are 2 for the FAS-030, 3 for the FAS-060,
and 4 for the FAS-120.
・
Be sure to double check the channel ID numbers and the
model number after you input them.
4. Check to make sure that the instantaneous flow rate display
shows zero.
5. Apply pressure to the flow meter and inside the piping, and
check to make sure that the instantaneous flow rate shows
zero when there is no flow.
6. Be sure to check and make sure there are no external leaks.
Reference: Channel ID numbers
"Channel ID numbers" are main channel characteristic
information that represent main channel's split flow ratio
adjustment values. Channel ID numbers 0, 1, and 2 correspond
to bypass flow ratio adjustment values 0, 1, and 2. Using
maintenance mode to write these values into the bypass unit
adjusts output to match the characteristics of each main
channel, which makes it possible to maintain accuracy even if
the bypass unit is replaced.
Removing the bypass unit
1. Prepare the following items: Safety glasses, helmet, gloves,
hex key (for M5, between flats 4 mm)
Note 1
2. Release the pressure from inside the flow meter and piping,
use a pressure gauge to confirm that pressure is zero.
3. Gradually loosen the four bolts that secure the bypass unit in
place and then remove them.
Note 2
Note 1: For safety, wear safety glasses when removing the
bypass unit.
2: Be sure to leave the gasket in place on the main
channel.
Bottom diagram of bypass unit
Rubber sheet
Orifice for bypass unit
Gasket
Note 2
Body number
label
Top diagram of main channel
(with bypass unit removed)
Front diagram of main channel
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