Burnham Boiler 108681-01 Temperature Sensor

Maintaining peak efficiency in condensing hydronic systems requires precise data, and the Burnham Boiler 108681-01 Temperature Sensor is the specific 10k ohm thermistor engineered for this role. As a veteran technician, you know that outdoor reset control is non-negotiable for maximizing the AFUE of Burnham Alpine boilers. This sensor provides the real-time ambient data necessary for the IQ Control System to adjust the boiler firing rate and supply water temperatures based on the outdoor reset curve. By communicating fluctuating external conditions, it prevents boiler short cycling and reduces thermal stress on the heat exchanger. The 108681-01 is the official direct replacement for 102946-01 and 101639-01, ensuring seamless HVAC sensor compatibility with series such as the 303BNI and 304BNI. This genuine OEM Burnham part features a robust NTC (Negative Temperature Coefficient) design, delivering reliable resistance-to-temperature correlation even in demanding North American winters. Proper placement on the north side of the structure, away from exhaust vents or direct sunlight, is essential to ensure the outdoor temperature sensor relays accurate signals for optimal fuel savings and consistent indoor comfort.

• Direct OEM Replacement: Fully compatible with legacy part numbers 102946-01 and 101639-01 for a drop-in fit.
• Optimized Efficiency: Enables outdoor reset functionality, potentially reducing fuel consumption by matching heat output to actual building heat loss.
• System Longevity: Minimizes "short cycling" by allowing the boiler to run at lower modulation for longer durations, reducing component wear.
• Precise 10k Ohm Resistance: Engineered to provide stable, accurate data to the Burnham Alpine control board across a wide temperature range.

What symptoms indicate a failing outdoor temperature sensor?
If the boiler display shows an "Outdr Senr Error" or if you notice the supply water temperature is fixed at the high limit regardless of outdoor conditions, the sensor or its wiring may be compromised. A mismatched resistance reading (e.g., reading 70°F when it is 30°F outside) will cause the boiler to under-fire or over-fire based on an incorrect curve.

Can I use 18-gauge thermostat wire for the extension?
Yes, using color-coded, 18-gauge wire is recommended for extending the run from the sensor to the IQ Option Panel. Ensure all connections are tight and the wiring hole is sealed with non-hardening caulk to prevent moisture ingress.

Where is the best location to mount this sensor?
Ideally, mount the sensor on the north-facing wall of the building. Avoid mounting it above doors, windows, or near dryer and boiler exhaust vents, as the artificial heat will skew the readings and degrade system performance.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.