1. Introduction
This manual provides detailed instructions for the installation, operation, and maintenance of your Heagstat H721 Non-Programmable Heat Pump Thermostat. The H721 is designed to control temperature in systems requiring 2 Heat and 1 Cool stages, specifically for heat pump systems or conventional single-stage systems.
Figure 1: Front view of the Heagstat H721 Thermostat, displaying room temperature, set temperature, time, and system status.
2. Package Contents
Verify that all items listed below are included in your package:
- Heagstat H721 Thermostat Unit
- Installation Manual
- Operation Manual
- Two (2) Screws and Anchors for mounting
- Cable Labels
Figure 2: Illustration of the items included in the Heagstat H721 Thermostat package.
3. Compatibility
The Heagstat H721 thermostat is designed for use with:
- Heat Pump Systems (2 Heat / 1 Cool)
- Conventional Single-Stage Systems (Gas, Oil, Electric Furnaces) up to 2 Heat / 1 Cool
Important Compatibility Notes:
- Not compatible with: 110-240V electric heat systems (e.g., electric baseboard heat, line voltage, convectors, radiant-ceiling heat).
- Not compatible with: Conventional multi-stage systems.
- Not compatible with: Mini-split systems.
- Not compatible with: 12V RV thermostats.
Before installation, confirm your existing system's compatibility and ensure the H721's dimensions (4.72"W x 3.86"H) can cover any marks left by your old thermostat.
Figure 3: Examples of incompatible wiring types. Ensure your system does not use stranded wires, thick stranded wires with wire nuts, or 110V/120V wiring.
4. Installation
4.1 Pre-Installation Steps
- Turn off Power: Before beginning, turn off the power to your heating and cooling system at the main circuit breaker or fuse box.
- Remove Old Thermostat: Carefully remove the cover of your old thermostat. Take a picture of the wiring connections for reference.
- Label Wires: Use the supplied cable labels to mark each wire according to its terminal on your old thermostat.
- Remove Old Base Plate: Unscrew and remove the old thermostat's base plate from the wall.
4.2 Mounting the New Thermostat
- Position the new H721 thermostat base plate against the wall where you want to mount it.
- Mark the screw holes on the wall.
- Drill pilot holes if necessary and insert the wall anchors.
- Secure the base plate to the wall using the provided screws.
Figure 4: Dimensions of the Heagstat H721 Thermostat for mounting reference.
4.3 Wiring Instructions
Connect the labeled wires to the corresponding terminals on the H721 thermostat's base plate. Refer to the wiring diagrams below and the terminal reference chart for correct connections.
Figure 5: Wiring terminal reference chart for Heat Pump and Conventional systems.
Figure 6: Detailed wiring diagrams for various system configurations.
4.4 Powering the Thermostat
The H721 thermostat is dual-powered, operating on either 24Vac hardwire power or two (2) AAA batteries (not included). For optimal performance and continuous backlight, hardwiring is recommended. If using batteries, ensure they are fresh and correctly inserted into the easy-access battery compartment.
Figure 7: Easy-access battery compartment for two AAA batteries.
After wiring and powering the thermostat, restore power to your heating and cooling system at the circuit breaker.
5. Operation
The H721 thermostat features a large, clear backlit digital display and intuitive button controls for easy operation.
Figure 8: Labeled controls and switches on the Heagstat H721 Thermostat.
5.1 Controls Overview
- Up/Down Arrows: Adjust the set temperature.
- FAN Switch (ON/AUTO): Controls fan operation.
- SYSTEM Switch (OFF/HEAT/COOL/EMH): Selects the operating mode.
- Menu Button: Accesses advanced settings (e.g., Tech Set, Set Time).
5.2 Setting the Temperature
Use the Up (▲) and Down (▼) arrow buttons on the right side of the thermostat to increase or decrease the desired set temperature. The display will show both the current room temperature and the set temperature.
Figure 9: Large digital display showing room temperature and set temperature.
5.3 System Mode Selection
Use the SYSTEM switch located at the bottom right of the thermostat to select one of the following modes:
- OFF: Turns off both heating and cooling.
- HEAT: Activates the heating system.
- EMH (Emergency Heat): For heat pump systems, this activates auxiliary or emergency heating.
5.4 Fan Operation
Use the FAN switch located at the bottom left of the thermostat to select one of the following fan modes:
- ON: The fan runs continuously, regardless of whether the heating or cooling system is active.
- AUTO: The fan runs only when the heating or cooling system is actively operating.
5.5 Special Features
- Accurate Temperature Control: Maintains temperature within +/-1°F of the set point.
- Temperature Display Range: 41°F to 95°F.
- Temperature Control Range: 44°F to 90°F.
- Heat or Cool Swing Setup: Adjustable from 0.2°F to 2°F, which influences how frequently the system cycles to maintain the set temperature.
- Room Temperature Calibration Adjustment: Allows for fine-tuning the displayed room temperature.
- 5 Minute Compressor Delay Protection: (Selectable ON or OFF) Prevents short cycling of the compressor, extending its lifespan.
- Air Filter Change Reminder: An indicator will appear on the display when it's time to change your air filter.
- Low Battery Indicator: An icon will display when the batteries need replacement.
6. Maintenance
6.1 Battery Replacement
When the low battery indicator appears on the display, replace the two (2) AAA batteries. Access the battery compartment from the front of the thermostat (refer to Figure 7).
6.2 Air Filter Maintenance
When the air filter change reminder appears, replace or clean your system's air filter according to the manufacturer's recommendations. This ensures optimal system performance and air quality.
7. Troubleshooting
If you experience issues with your Heagstat H721 thermostat, consider the following common solutions:
- No Display/Power: Check if the circuit breaker for your HVAC system is on. If using batteries, ensure they are fresh and correctly installed.
- System Not Responding: Verify that the SYSTEM switch is set to the desired mode (HEAT or COOL) and the FAN switch is set to AUTO or ON. Check wiring connections for looseness.
- Incorrect Temperature Reading: If the displayed room temperature seems inaccurate, you may need to perform a room temperature calibration adjustment (refer to the full operation manual for detailed steps).
- Compressor Short Cycling: Ensure the 5-minute compressor delay protection is enabled.
For persistent issues, consult a qualified HVAC technician.
8. Specifications
| Brand | Heagstat |
| Model Number | H721 |
| Product Dimensions | 0.98"D x 4.72"W x 3.86"H |
| Controller Type | 24V Heat Pump Thermostat |
| Power Source | Dual Powered (24Vac hardwire or 2x AAA batteries) |
| Voltage | 24 Volts (AC) |
| Temperature Control Type | Heating and Cooling |
| Temperature Control Range | 44°F to 90°F |
| Room Temperature Display Range | 41°F to 95°F |
| Accuracy | +/-1°F |
| Display Type | Digital with White Backlight |
| Screen Size | 4.5 sq. inches (approx.) |
| Control Type | Button Control |
| Mounting Type | Wall Mount |
| Material | Plastic |
| Item Weight | 7.68 ounces |
| UPC | 712215337375 |
9. Warranty and Support
The Heagstat H721 Thermostat comes with a 2-year Worry-Free Warranty. Additionally, the product includes a 30-day free return policy.
If you encounter any problems or require assistance, please contact Heagstat customer support. We aim to respond within 24 hours.