Resideo T827K1009 Thermostat

The Resideo T827K1009 is a professional-grade, mercury-free economy thermostat engineered for precise 1-stage heat-only applications. This millivolt thermostat is highly versatile, supporting both 12Vdc and 750 mV systems, making it a reliable choice for gravity-fed heating, floor furnaces, and wall heaters. Built with a bimetal sensor element and SPST switching action, it ensures consistent performance with a ±2 degree accuracy. The 45-95 degree Fahrenheit temperature range provides flexible setpoint control in various residential and light commercial environments. Designed for vertical mounting, the Premier White housing offers a clean, unobtrusive look on any job site. For technicians performing retrofits or new installations, this low voltage heat-only thermostat provides a straightforward, non-programmable interface that eliminates complex service calls while maintaining tight thermal regulation in single stage heating setups.

• System Compatibility: Operates on 750 mV millivolt systems or 12Vdc circuits, providing flexibility for older heating equipment.
• Rugged Construction: Features a robust bimetal sensor and SPST switch for long-term mechanical reliability in demanding environments.
• Environmental Compliance: Fully mercury-free design meets modern disposal regulations and environmental standards.
• Precision Control: Maintains temperature within a tight ±2 degree variance for stable indoor climates.
• Simplified Installation: Vertical orientation and simple wiring terminals streamline the mounting process for field contractors.

Can I use the T827K1009 with a standard 24V HVAC transformer?
No, this specific model is engineered for 12Vdc or 750mV millivolt systems. Professional installers should verify the secondary voltage of the heating system before wiring to prevent damage to the bimetal sensor.

Does this thermostat require batteries for operation?
This is a mechanical, non-programmable thermostat that does not require batteries. It utilizes the millivoltage generated by the pilot light's thermopile or a dedicated 12Vdc circuit to actuate the switch.

What is the proper procedure for calibrating the temperature setpoint?
The T827K1009 is factory-calibrated. If a temperature offset is observed, ensure the unit is leveled correctly during vertical mounting and that internal wall drafts are sealed to prevent inaccurate bimetal sensor readings.

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.