Resideo TH1110D2009 Thermostat

Upgrade your single-stage control with the Resideo TH1110D2009 T1 Pro Non-Programmable Thermostat, the professional-grade replacement for legacy Honeywell TH3110D1008 and 8403-057 models. Engineered specifically for 1 Heat / 1 Cool conventional systems and single-stage heat pumps without auxiliary heat, this unit features the standardized UWP mounting system. This allows for rapid equipment change-outs and future-proofs the installation, as the mounting bracket is compatible across the entire T-Series range.

The TH1110D2009 utilizes soft-key controls and a 2.37 sq. in. backlit digital LCD display, providing clear visibility in low-light mechanical rooms or residential hallways. Contractors can choose between 24 VAC hardwired (C-wire) power or 2x AA battery operation, ensuring flexibility for retrofits where common wires are unavailable. The manual changeover interface (Heat-Off-Cool) and Auto/On fan settings deliver a reliable "set-it-and-forget-it" solution for rental properties or light commercial applications.

Primary Technical Benefits:

• Universal Mounting: Includes the UWP mounting system and J-box adapter for standardized installation across different HVAC platforms.
• Broad Compatibility: Supports 24 VAC systems including gas, oil, electric warm air, hot water coils, and steam/gravity systems.
• Precise Control: Maintains temperature accuracy within ± 1°F with an operating range of 32°F to 102°F.
• Contractor-Focused Design: Features an easy-to-access front battery door and simple push-button navigation for reduced callback rates.
• OEM Reliability: Genuine Resideo T1 Pro hardware ensures industrial-standard performance in environments with 5-90% non-condensing relative humidity.

Common Contractor Questions:

Is the TH1110D2009 compatible with 2-stage heat pump systems?
No, this model is designed for 1H/1C conventional or single-stage heat pump systems without auxiliary heat. For multi-stage applications, a T4 or T6 Pro series model is required.

Can I install this thermostat without a C-wire?
Yes, the TH1110D2009 is dual-powered and can operate strictly on two AA batteries if a common wire is not present at the terminal block.

Does this unit support automatic changeover?
This specific T1 Pro model features manual changeover, meaning the user must manually switch the system between heating and cooling modes via the "Menu" or system toggle.

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.