Trane VariTrac VAV-SVN03A-EN, Руководство по установке

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VAV-SVN03A-EN 48
Zone Sensor Failure
If the zone sensor fails, the damper drives to minimum position, and its vote
is excluded.
Zone Setpoint Failure
If a setpoint fails, the UCM automatically uses the edited occupied cooling
and heating setpoints.
Auxiliary Sensor Failure
If the auxiliary sensor circuit opens, the temperature reading on the display
screen reads and a diagnostic is be displayed on the operator display and
PC software. If the auxiliary sensor is used on a stand alone UCM to
establish the control action, the UCM remains in the current control action.
Static Pressure Sensor Troubleshooting
The static pressure sensor signal enables the CCP to recognize system static
and adjust the bypass damper accordingly. If a problem exists with the
sensor or its location, the bypass damper controls with default values. If a
“failure” persists, perform the following:
1 On the communicating sensor/bypass control UCM, read the voltage
across J3-1 (green wire) and J3-3 (red wire). Voltage should be between
4.50 Vdc and 5.50 Vdc.
2 Read the transducer output voltage across J3-1 (green wire) and J3-2
(black wire). Voltage should be between 0.20 Vdc and 0.45 Vdc. Record the
zero flow voltage.
3 Wait approximately 4 minutes after power-up for the system fan to start.
Read the transducer output voltage again across J3-1 (green wire) and
J3-2 (black wire). The difference between this voltage and the zero flow
voltage should be 0.10 Vdc minimum.
4 If a defective transducer is suspected, check the output voltage with a
low-pressure source and Magnahelic gauge. Record the zero flow volt-
age. Connect a low-pressure source and Magnahelic gauge to the “hi”
port of the transducer. Input 1 inch of pressure. The voltage should be
approximately 0.750 Vdc greater than the zero flow voltage. The reading
on the voltmeter will include the zero flow voltage.
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CAUTION
Do not exceed 2 inches of input pressure to avoid damaging the tranducer.
Signal change must be 0.10 Vdc minimum or a “AHU air flow” “failed”
message will be displayed
Zone, Auxiliary and System Temperature Sensor
Checkout
If temperature is reported to the UCM or CCP seems wrong use the
temperature-resistance table (Table 4) to verify the integrity of the adjustable
setpoint potentiometer or the sensor. Measure resistance across the
terminals the device is connected to. For details of terminal connections see
the Installation and Wiring section of this manual.
Tests and Troubleshooting