Introduction
The Honeywell TR21-A Remote Temperature Sensor Wall Module is designed to provide accurate temperature readings for HVAC systems. This 10K ohm NTC non-linear sensor is specifically intended for use in applications requiring temperature averaging from multiple sensors, or with compatible thermostats such as the T7350 and TB8220. Its compact design allows for discreet wall mounting, ensuring precise environmental monitoring.
Image of the Honeywell TR21-A Remote Temperature Sensor Wall Module, a compact white rectangular device designed for wall mounting.
Setup and Installation
Follow these steps for proper installation of your Honeywell TR21-A Remote Temperature Sensor Wall Module:
- Mounting Location: Select a suitable indoor wall location, away from direct sunlight, drafts, or heat sources that could affect temperature readings. The sensor should be placed at a representative height for accurate room temperature measurement.
- Mounting: The TR21-A module is designed to be mounted on a standard 2 x 4 inch junction box or a 60 mm diameter junction box. Secure the module firmly to the chosen box using appropriate fasteners.
- Wiring: Connect the sensor to the compatible thermostat or control system according to the specific wiring diagrams provided with your primary control unit (e.g., T7350, TB8220). Ensure all connections are secure and follow local electrical codes. This sensor is a 10K ohm NTC type.
- Final Check: After mounting and wiring, ensure the module is securely attached and all connections are correct before powering on the system.
Operating Instructions
The Honeywell TR21-A is a passive remote temperature sensor. It does not have user-adjustable controls or indicators. Its primary function is to provide accurate temperature data to a connected thermostat or building management system.
- Temperature Averaging: When used in conjunction with other sensors, the TR21-A contributes to an averaged temperature reading across a larger area, providing more consistent climate control.
- Compatibility: This sensor is compatible with specific Honeywell thermostats, including the T7350 and TB8220, which are designed to interpret its 10K ohm NTC signal. Refer to your thermostat's manual for details on integrating remote sensors.
Maintenance
The TR21-A Remote Temperature Sensor requires minimal maintenance to ensure continued accurate operation.
- Cleaning: Periodically wipe the exterior of the sensor with a soft, dry cloth to remove dust. Do not use abrasive cleaners or solvents, as these may damage the casing or internal components.
- Inspection: Annually inspect the sensor for any visible damage or loose connections. Ensure the mounting remains secure.
- Calibration: This sensor is factory calibrated and typically does not require field calibration. If temperature discrepancies are suspected, consult the manual of your connected thermostat or control system for diagnostic procedures.
Troubleshooting
If you encounter issues with your TR21-A sensor, consider the following:
- Incorrect Temperature Readings:
- Verify that the sensor is installed in an appropriate location, away from heat sources, drafts, or direct sunlight that could influence its readings.
- Check all wiring connections between the sensor and the thermostat/control system for looseness or corrosion.
- Ensure the sensor is compatible with the connected thermostat/control system (e.g., T7350, TB8220).
- System Not Responding to Sensor:
- Confirm that the thermostat or control system is correctly configured to recognize and utilize the remote sensor. Refer to the thermostat's manual for setup procedures.
- Check for continuity in the sensor wiring to ensure there are no breaks in the circuit.
- Physical Damage: If the sensor appears physically damaged, it may need to be replaced. Contact Honeywell support or a qualified HVAC technician for assistance.
Specifications
| Feature | Detail |
|---|---|
| Model Number | TR21-A |
| Sensor Type | 10K ohm NTC (Negative Temperature Coefficient) non-linear thermistor |
| Dimensions (H x W x D) | 4 13/16 in. (12.2 cm) x 3 in. (7.6 cm) x 7/8 in. (2.2 cm) |
| Mounting | Standard 2 x 4 inch junction box or 60 mm diameter junction box |
| Application | Designed for temperature averaging applications; compatible with T7350, TB8220 Thermostats |
| Manufacturer | Honeywell |
| Contents | Sensor module |
