Rev A1
FT900003
11 of 14
CALIBRATION
Step Eight
Set Point:
If the preset factory calibration is not adequate for your application, follow the calibration steps
listed below.
Note:
The switch’s internal LED will be on when the switch detects no‐flow and will off when the switch
detects flow, regardless of the polarity of the Red and Black wires. Reversing the Red and Black wires will
reverse the polarity of the relay switch, but not the internal LED.
1.
Install the fitting and flow switch as described in the Installation section of this manual. Turn the flow
switch and controller power on and adjust the flow rate to the application setting. If the medium to be
sensed is likely to be subject to any temperature variation, the flow switch should be set as the highest
normal temperature likely to be encountered.
2.
Locate the potentiometer knob at the top of the flow switch. The red LED is visible through the
potentiometer. The adjustment is a single turn 270° potentiometer. The initial response time of the flow
switch after adjustment is 1 to 10 seconds. Adjust the potentiometer in slow increments and wait for the
response.
a.
LED is ON ‐ If the LED is on, slowly adjust the potentiometer counter‐clockwise, with a small flat head
screwdriver until the LED turn off.
b.
LED is OFF ‐ If the LED is off, slowly adjust the potentiometer clockwise. with a small flat head
screwdriver until the light turns on.
3.
Adjust the potentiometer back and forth where the LED is switching, eventually settling for where the LED
is OFF (this is the low flow state for the switch).
a.
If the flow is increased, the LED will remain OFF indicating a flow condition
b.
If the flow is decrease, the LED will turn ON indicating a no‐flow condition.
4.
Verify that the new calibration is correct by lowering the system flow rate below the set point and check to
see that the red LED turns on. Then increase the flow rate above the set point and verify that the red LED
turns off accordingly.
FT10 Flow Switch
(Liquid Only)
Potentiometer
Location
GT10 Flow Switch
(Gas Only)
