6
F
AULT INDICATION
TROUBLESHOOTING
T
D1/TD2 have continuous diagnostics to ensure that the signal from the sensor is within a select range. If the electronics detect
an “out of range” signal, the switch has registered an instrument error.
TD1: Alarm LED blinks and the relay de-energizes.
TD2: 3,6 mA signal when unit is set for low level fail-safe.
22 mA signal when unit is set for high level fail-safe.
Alarm LED blinks and the relay de-energizes.
If a fault is detected, refer to section “TROUBLESHOOTING”.
The TD1/TD2 switches have various settings to handle a wide variety of flow and level applications. If the switch is not per-
forming properly, check the switch settings on page 4 or the following:
Symptom Problem Solution / Action
Red LED does not go ON Switch point cannot be established for
air flow detection
Check whether probe is extended into
the flow.
Change Heater to “-”
Green LED OFF (TD1)
All LED’s OFF (TD2)
No power 1. Check power supply
2. Check wiring at wiring terminals
Red LED blinks and ≤ 3,6 mA or
≥ 22 mA (TD2)
An instrument error has been regis-
tered
By changing the switch settings, the
unit may return to normal operation
mode. If not, consult factory.
Symptom Application Action*
Unable to adjust set point
to obtain alarm
Fault LED blinks
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 “RESISTANCE VALUES”. Probe
and/or electronics 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 “RESISTANCE VALUES”. Probe
and/or electronics may need to be replaced.
Liquid Flow – Sensor Dry
or
No Air Flow
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 “RESISTANCE VALUES”. Probe
and/or electronics 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 “RESISTANCE VALUES”. Probe
and/or electronics may need to be replaced.