Wired Zone Sensor Setpoint Failure - Trane Symbio 210 Installation, Operation And Maintenance Manual

Wired Zone Sensor Setpoint Failure

Hazardous Service Procedures!
Failure to follow all precautions in this manual and on the tags, stickers, and labels could result
in death or serious injury.
Technicians, in order to protect themselves from potential electrical, mechanical, and chemical
hazards, MUST follow precautions in this manual and on the tags, stickers, and labels, as well
as the following instructions: Unless specified otherwise, disconnect all electrical power
including remote disconnect and discharge all energy storing devices such as capacitors
before servicing. Follow proper lockout/tagout procedures to ensure the power can not be
inadvertently energized. When necessary to work with live electrical components, have a
qualified licensed electrician or other individual who has been trained in handling live electrical
components perform these tasks.
In the event that the Symbio 500 controller reports an incorrect zone setpoint, check the following:
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BAS-SVX091A-EN
Verify that the zone sensor is wired correctly.
Check that the zone sensor setpoint dial is not defective.
– Disconnect the zone sensor terminal plug from the Symbio 500 controller and using an
ohmmeter, measure the resistance across the terminals 2 (common) and 3 (setpoint). Compare
the resistance to specified setpoint on sensor using . The resistance shown should correlate
within ± 2 degrees of setpoint. If not, replace the zone sensor.
Check the wiring and the Symbio 500 controller.
– With the wires still connected to Symbio 500 controller, disconnect zone sensor setpoint wires
and check voltage (direct current) from wires that were connected to terminals 2 and 3 of zone
sensor. Measure for 2.6–3.0 Vdc and if not present, then verify whether the Symbio 500
controller is outputting 2.6–3.0 Vdc.
To do this, disconnect the wires on the Symbio 500 controller on terminals Ground
AI2 and measure the Vdc– it should be 2.6–3.0 Vdc. If there is 2.6–3.0 Vdc at the Symbio
500 controller, the wires going to the zone are OPEN. If 2.6–3.0 Vdc is not present, check
the incoming power to the Symbio 500 controller on XFMR 24 Vac input and
measure 24 Vac ± 15%. If the proper voltage is measured at the XFMR 24 Vac input and
, and there is no voltage at the and AI2, replace the Symbio 500 controller.
Verify that the zone sensor setpoint is not shorted out.
– Check the resistance across the wires. Disconnect wires from the Symbio 500 controller and
zone sensor making sure the ends are not touching each other and measure resistance. It
should be infinity or no conductivity. If lower resistance is shown, then the wires are shorted
together and need replacing.
WARNING
Troubleshooting
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