Dwyer TBS - Manual (Page 7)

TRoUBlESHooTInG and REPaIR
CAUTION! Never attempt to remove a
flow sensor when there is pressure in
the pipe. Loosen the compression nut
slowly to release any trapped pressure.
If fluid sprays out when removing the
sensor, stop turning and depressurize the pipe. Fail-
ure to do so could result in the sensor being thrown
from the pipe, resulting in damage or serious injury.
WaRRanTY/RETURn
Rotor Replacement. Rotors are easily field-replaced. Shaft
and rotor are a single unit, and are not replaced separately.
If replacement is due only to normal shaft wear, bearing re-
placement is probably not necessary. If the rotor has been
damaged by impact, the bearings should also be replaced.
Rotor and bearings can be ordered as a kit (see parts listing).
Follow these steps:
1. Unscrew the threaded bearing housings to expose the
shaft ends. If bearings are being replaced, back them
completely out.
2. Remove the rotor. Put the new rotor in its place.
3. Thread in one bearing housing part way, then the
other. Take care to start the end of the shaft into
the bearing hole before tightening further.
4. Screw in bearing housings until they bottom.
note: Do not use excessive force.
5. Check for free spin. Blowing lightly on the rotor
should result in it spinning rapidly and coasting
to a smooth stop.
shaft
Turbine Rotor
Bearing
housing
The flow sensor has only one moving part, the rotor. If this
is turning properly and there is no signal, the Hall-effect
sensor is not operating properly. To check the signal, ap-
ply 12 VDC regulated* power to the red (+) and black (-)
leads. Set a multimeter to voltage reading. Put the positive
multimeter lead on the red wire and the negative lead on
the white wire. Slowly turn the rotor. Voltage reading should
swing between +12 Volts and 0 Volts as the rotor turns. If
it does not, the Hall effect sensor is not working properly.
Checking for continuity is not a useful test of these sensors.
*noTE: An unregulated power supply can exceed max voltage of
micro powered sensor (gray cable) and damage sensor.
Refer to "Terms and Conditions of Sale" in our catalog or on
our website. Contact customer service to receive a Returns
Goods Authorization number before shipping your product
back for repair. Be sure to include a brief description of the
problem plus any relevant applciation notes.
Troubleshooting
PL-OM-65200391-091912
9/19/12
Dwyer Instruments, Inc. • 102 Indiana Highway 212 • Michigan City, IN 46360 • USA
(P) 219.879.8868 • (F) 219.872.9057 • 1.800.872.9141 • www.dwyer-inst.com