Troubleshooting (continued)
DETECTING DAMPER PROBLEMS | ||
Symptom | Possible Solution | |
|
| |
| DAS shorted or open causing the panel to only respond | |
| to zone 1 inputs while not closing any dampers. | |
Damper opens when it should be closed. |
| |
Damper wired incorrectly. Spring open power close | ||
| ||
| dampers should be connected between NO and | |
| C terminals. | |
|
| |
| DAS shorted or open causing the panel to only respond | |
Damper will not close. | to zone 1 inputs while not closing any dampers. | |
| ||
| Damper motor faulty. | |
|
| |
CHECKING THERMOSTAT VOLTAGES
Using a digital voltmeter (DVM) measure the AC voltage supplied at the R and C terminals of the Thermostat inputs on the control panel for the zone in question. This voltage should be same as the voltage supplied to the control panel 24VAC terminals. Make a call for heat, cooling or fan. Measure the voltage across the terminal that should be energized (i.e. W for heat, Y for cooling, etc.) and the C terminal. This should be the same voltage as there is between the R and C terminals. Measure the voltage across a terminal that should NOT be energized and the C terminal; this voltage should be zero.
DISCHARGE AIR SENSOR CHECKOUT
The discharge air sensor is a temperature dependent resistor; the higher the temperature, the lower the resistance. In order to confirm the sensor is working, both sensor leads must be disconnected from the zone panel board. Using a digital voltmeter (DVM) set to read resistance, touch the leads from the sensor to the probes of the DVM. Take care not to create a parallel resistance path through your body by touching both probes with your fingers or a faulty reading will be obtained. At 77F, the resistance of the sensor will be 10K ohm. If the sensor is cooler than 77F, the resistance will be higher, if it is warmer, the resistance will be lower. After reading the resistance at room temperature, warm the tip of the sensor by holding it in the palm of your hand, and take another resistance reading. This reading should be noticeable lower than the room temperature reading.
Temperature (°F) | Resistance (ohms) |
65 | 13476 |
70 | 11884 |
75 | 10501 |
80 | 9298 |
85 | 8249 |
90 | 7333 |
The zone panel is well equipped to monitor the operation of the probe and determine if a failure has occurred.
The probe should be considered an integral (but replaceable) part of the zone panel. The zone panel will indicate if the probe is operating improperly and needs to be replaced.
B2203458
10006259
Page 12
