15
54-610 Thermatel Model TD1/TD2 Flow Level Switch
3.5
Troubleshooting
The TD1/TD2 switches have various settings to handle a wide variety of flow and level applications.
If the switch is not performing properly, check the switch settings on page 6 or the following:
Symptom
Application
Action
Unable to adjust set point to
obtain alarm
Air Flow Detection
Ensure that the probe is extended into the flow
Change HEATER (Model TD1) / HTR (Model TD2) to “–”
Switch indicates a fault (red
LED will blink)
Liquid Level – Sensor Wet
Verify HEATER (TD1) / HTR (TD2) is set to “–”
Change HEATER/HTR to “+”
Light goes off—contact factory to discuss
application
Light stays on—check resistance to determine if a problem exists
with the probe or electronics. Refer to Section 3.4,
Resistance Values on page 14. Probe and/or elec-
tronics may need to be replaced.
Liquid Level – Sensor Dry
Verify HEATER (TD1) / HTR (TD2) is set to “–”
Turn off FAULT (TD1) / FLT (TD2)
Light goes off—operate in this mode
Light stays on—check resistance to determine if a problem exists
with the probe or electronics. Refer to Section 3.4,
Resistance Values on page 14. Probe and/or elec-
tronics may need to be replaced.
Liquid Flow – Sensor Dry
or
Air Flow – None
Turn off FAULT (TD1) / FLT (TD2)
Light goes off—run HEATER/HTR at “+” and FAULT/FLT “off” or run
HEATER/HTR at “-”
Light stays on—check resistance to determine if a problem exists
with the probe or electronics. Refer to Section 3.4,
Resistance Values on page 14. Probe and/or elec-
tronics may need to be replaced.
Liquid Flow – Sensor Wet No Flow
Switch HEATER/HTR to “-”
Light goes off—run HEATER/HTR at “+” and FAULT/FLT “off” or run
HEATER/HTR at “-”
Light stays on—check resistance to determine if a problem exists
with the probe or electronics. Refer to Section 3.4,
Resistance Values on page 14. Probe and/or elec-
tronics may need to be replaced.
Liquid Flow – Flow Present
Turn off TEMP COMP (TD1) / TC (TD2)
Light goes off—operate in this mode
Light stays on—check resistance to determine if a problem exists
with the probe or electronics. Refer to Section 3.4,
Resistance Values on page 14. Probe and/or elec-
tronics may need to be replaced.
Air Flow – Flow Present
Switch HEATER/HTR to “-”
Light goes off—Operate at lower heater power (with less
sensitivity). Turn TEMP COMP/TC off if problem con-
tinues (requires re-calibration) or operate at
HEATER/HTR “+” and make sure FAULT/FLT switch
is “off”
Light stays on—Turn TEMP COMP/TC “off”. If light goes off then
recalibrate and operate in this mode. If light stays
on check resistance to determine if a problem exists
with the probe or electronics. Refer to Section 3.4,
Resistance Values on page 14. Probe and/or elec-
tronics may need to be replaced.
