Honeywell TR21 Indoor Wall Module 20K Ohm NTC Non-Linear Temperature Sensor

The Honeywell TR21 is an indoor wall-mounted temperature sensor module, also called a space temperature wall module. It uses a 20K ohm NTC non-linear sensor to measure room temperature for compatible Honeywell HVAC controls.

Key Features:

• 20K ohm NTC (negative temperature coefficient) non-linear temperature sensor
• Direct-wired wall module for indoor space temperature sensing
• White finish
• Mounts on a standard 2" x 4" junction box or a 60 mm diameter junction box
• Networked sensor type without a network jack
• Use with Honeywell T7351 and TB8220

Mount it on an interior wall away from direct sunlight, water pipes and air ducts, which can skew the temperature reading.