Domestic Furnace Thermostat Manual

The Domestic Furnace Thermostat is a programmable temperature control device designed for residential heating systems. It features digital display, programmable schedules, temperature hold functions, system mode selection (heat/cool/off), fan control (auto/on), battery backup, filter change reminder, and compatibility with most standard furnace systems. Below are key sections for safety, features, installation, programming, operation, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. System Configuration 7. Programming Schedule 8. Advanced Features 9. Maintenance 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Digital LCD display, Menu buttons, Up/Down temperature controls, System mode selector, Fan control, Hold button, Program button.

Feature	Description
Digital Display	Shows current temperature, set point, and system status
Programmable Schedule	4 time periods per day for energy savings
Temperature Hold	Temporary override of programmed schedule
System Mode	Heat/Cool/Off selection
Fan Control	Auto or Continuous operation
Battery Backup	Maintains programming during power outages
Filter Change Reminder	Alerts when furnace filter needs replacement
Keypad Lock	Prevents unauthorized changes to settings
Backlight	Illuminates display in low light conditions
Compatibility	Works with most 24VAC heating/cooling systems

Installation

Turn off power to furnace before installation. Select location away from drafts, direct sunlight, and heat sources.

Remove old thermostat: Turn off power, label wires, remove from wall.
Mount new baseplate: Level and secure to wall, route wires through center.
Connect wires: Match wire labels to terminal screws (R, W, Y, G, C).
Attach thermostat: Snap onto baseplate, restore power.
Configure settings: Follow first-time setup procedure.

WARNING! Always turn off power at circuit breaker before installation to prevent electrical shock.

First-Time Setup

After installation and power restoration, configure basic settings.

Set date and time: Press MENU, navigate to Clock Settings.
Select temperature format: Fahrenheit or Celsius.
Configure system type: Conventional or Heat Pump.
Set filter reminder interval: Default 90 days.
Test system operation: Verify heating and cooling functions.

CAUTION! Ensure proper wire connections before restoring power to prevent system damage.

Specifications

Power Requirements: 24VAC from furnace or 2 AA batteries
Temperature Range: 40°F to 90°F (4°C to 32°C)
Temperature Accuracy: ±1°F (±0.5°C)
Display: Backlit LCD with indoor temperature and set point
Programming: 7-day programmable, 4 periods per day
Compatibility: Most 24VAC heating/cooling systems
Wire Terminals: R, W, Y, G, C standard connections
Battery Backup: Maintains programming for 24 hours
Operating Environment: 32°F to 105°F (0°C to 40°C)

Controls and Settings

Front panel controls: Up/Down arrows, Menu, Hold, Fan, System Mode.

Menu Navigation: Press MENU to access programming, settings, and system configuration.

Temperature Control: Use Up/Down arrows to adjust set point. System Mode: HEAT for winter, COOL for summer, OFF for system shutdown. Fan Control: AUTO runs with heating/cooling cycles, ON provides continuous air circulation. Hold Function: Temporarily overrides programmed schedule. Program: Set different temperatures for Wake, Leave, Return, Sleep periods.

System Configuration

Access system settings through MENU > Installation Settings.

System Type: Conventional or Heat Pump
Fan Control in Heat Mode: Gas/Electric or Heat Pump
Cycle Rate: Number of cycles per hour (3, 4, 5, or 6)
Temperature Differential: Minimum temperature change before system activates
Backlight Settings: Always on, Auto-dim, or On when pressed

Tip: Consult HVAC professional for proper system configuration settings.

Programming Schedule

Create energy-saving schedule with different temperatures for different times.

Press MENU and select Program Schedule
Select day type: Weekday/Weekend or 7-Day programming
Set Wake time and temperature (typically 6:00 AM, 68°F)
Set Leave time and temperature (typically 8:00 AM, 62°F)
Set Return time and temperature (typically 6:00 PM, 68°F)
Set Sleep time and temperature (typically 10:00 PM, 62°F)
Repeat for each day type as needed
Press DONE to save programming

WARNING! Do not set temperatures below 55°F in winter to prevent pipe freezing.

Advanced Features

Filter Change Reminder: Program interval (30-365 days) in Maintenance menu. Keypad Lock: Prevent unauthorized changes in Settings menu. Adaptive Recovery: Learns how long system takes to reach temperature. Vacation Hold: Extended temperature hold for extended absences.

Maintenance

Replace batteries annually or when low battery indicator appears. Clean display with soft, dry cloth. Do not use chemicals or abrasives.

CAUTION! Turn off power before cleaning or battery replacement. Keep away from moisture.

Regulatory Information

UL Listed: Complies with UL 873 safety standards. FCC Part 15: Class B digital device; complies with interference limits for residential use. Copyright © 2025 Domestic Heating Products; all rights reserved. For technical support, visit www.domesticfurnace.com or contact 1-800-555-HEAT.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Blank display	Dead batteries or power loss	Replace batteries; check circuit breaker; verify 24VAC at terminals
System not heating	Incorrect settings or furnace issue	Check system mode (HEAT); verify set point above room temperature; check furnace power
Temperature inaccurate	Location or calibration	Relocate away from heat sources; check calibration in advanced settings
Programming lost	Battery failure	Replace batteries; reprogram schedule
Fan runs continuously	Fan setting or relay issue	Check fan setting (AUTO/ON); verify G terminal connection

Reset: Remove batteries for 30 seconds to reset to factory defaults.

Service: 1-800-555-HEAT; www.domesticfurnace.com