Electronic Zone Sensor Check - Trane VariTrane Installation/ Owner Programming

3. Slowly rotate the zone sensor until the
amber LED on the circuit board
illuminates. Voltage at terminal TP2 to
ground should be approximately
3.2 volts DC.
4. Continue rotating the zone sensor until
the first stage of heat energizes. This
can be determined by voltage across
terminals J7 to J9. At this point, the
green LED on the circuit board should
illuminate. Voltage at terminal TP2 to
ground should be 3.9 volts DC or
higher. R68 should be in control.
5. Now adjust the zone sensor so that the
output voltage at terminals 2 and 3 is
6.0 volts DC, +.01 volts DC, -.01
volts DC.
6. Compare the actual zone sensor to the
indicated setpoint on the dial of the
zone sensor. If the two readings are
within 3°F of each other, then the zone
sensor is within standard calibration
tolerance. Calibration procedures are
described in the Calibration Section in
this manual.
7. Note position of R69. Rotate
potentiometer R69 clockwise and
counter-clockwise while watching the
amber and green LED's to make sure
that the control is now with minimum
potentiometer R69.
8. Return R69 to its original position.
VAV-SVX03A-EN
Troubleshooting
Electronic Zone Sensor
Check
Note: The following checkout procedures
will be used when power is applied to
the electronic zone sensor.
1. Room temperature must be between
65°F and 80°F . Make sure also that
placement of the zone sensor is
satisfactory. It should not be located in
direct sunlight, on cold or hot wall
surfaces, etc. A zone sensor or other
accurate temperature measuring
device should be installed next to the
zone sensor. It is preferable to mount
the temperature sensing element
under the zone sensor cover next to
the thermistor of the zone sensor. (the
Thermistor is a small electronic
temperature sensing device
imbedded in a glob of silicone
cement.)
2. Remove the zone sensor cover.
3. Attach a volt meter to terminals 2 (+)
and terminal 3 (-).
4. Record temperature in zone. It should
be between 65°F and 80°F .
5. Check the voltage a terminals 2 (+)
and terminal 3 (-). If the zone
temperature and the zone sensor
setpoint are at equilibrium, the voltage
at this point should be 6.00-volts DC.
6. Rotate the zone sensor to the full-
heating position. Allow five minutes for
the zone sensor to equalize setpoint.
The voltage on terminals 2 and 3
should drop to 5.5-volts DC or less.
7. Rotate the zone sensor to the full
cooling position. The voltage on
terminals 2 and 3 should rise to
6.3-volts DC or higher.
Jack Numbering Designations
for Analog Control Boards
Jack Function
J1 Motor
J3 Transducer
J9 Stage 1 Contact
J10 Stage 2 Contact
J1 1 Stage 3 Contact
J15 Drive MAX (constant volume)
J18 Auto Dual Minimum
J19 Output Override
TB1 Field Connections: Power and Zone
Sensor
19