Rev A1
FT900003
13 of 14
MAINTENANCE
Step Ten
Testing the Sensor (GT10 Series Only):
1.
Creating a No‐Flow Test Point:
The purpose of this step is to create a no‐flow state for the sensor to be
tested against. Since this is a low flow switch, even a buildings HVAC system can create a flow that the
sensor can read.
a.
Place the switch on a table and place an empty cup over the sensing tips.
b.
The cup will act like a shield to protect the sensor from air flow.
2.
Power:
Turn on power to the switch with Red to (+) and Black to (‐)
.
You can reverse the polarity if
desired.
3.
No‐Flow/Flow Test:
With the switch setting still under the cup, wait until the Red LED turns ON (no‐flow
condition).
a.
Remove the cup and move the sensor in air and observe when the Red LED turn OFF (flow
condition).
b.
Place the sensor on the table and place the cup over the sensor and let it rest waiting for the
Red LED to turn ON again (no‐flow condition).
c.
Repeat the above two steps.
4.
Relay Test:
Connect a multimeter (set to read Ohms) to the White and Green Wires. Perform the above
No‐Flow/Flow test with the multimeter connect to observe the actuation of the relay.
a.
With Red to (+) and Black to (‐), the multimeter will read a small resistance during no‐flow
(closed relay) and OL during a flow condition (open relay).
b.
Reverse Polarity [Red to (‐) and Black to (+)] to see the multimeter read OL during a no‐flow
state (open relay) and a small resistance during a flow condition (closed relay).
The No‐Flow/Flow test determines if the switch is capable of sensing the changes between no‐flow and flow.
The Relay test determines the ability of the relay to switch between a no‐flow and flow condition. This is the
basic test to determine functionality of the sensor.
