Introduction
This manual provides detailed instructions for the installation, operation, and maintenance of your UPM THM303A 24-Millivolt Low Voltage Central Heating/Cooling Programmable Thermostat. The THM303A is designed to replace common residential thermostats and is compatible with most electric, oil, or gas heating and air-conditioning systems. It features separate programming for weekdays, Saturday, and Sunday, with up to four program periods per day, and includes built-in protection for the air-conditioner compressor.
Figure 1: Front view of the UPM THM303A Thermostat, displaying current temperature, humidity, and time.
Key Features
- Low Voltage Compatibility: Operates with Millivolt/24 Volt systems.
- Extra Large LCD Display: Features a clear, backlit display for easy reading.
- Real-time Clock: Selectable 12- or 24-hour display format.
- 5+1+1 Day Programming: Allows for customized schedules with 4 program periods per day for weekdays, Saturday, and Sunday.
- Separate Heat/Cool Programs: Independent programming for heating and cooling cycles, including built-in protection for the air-conditioner compressor.
- Temperature Display Options: Display and set temperature in either Celsius (°C) or Fahrenheit (°F).
- Relative Humidity Display: Shows current relative humidity in percentage.
- Pre-comfort Recovery System: Initiates heating or cooling a half-hour before the preset time to reach the desired temperature by the scheduled start.
- Automatic Temperature Control: Interfaces with heating or air-conditioning systems for precise temperature management.
- Automatic Humidity Control: Interfaces with a humidifier for automated humidity regulation.
- Low Battery Notification: Flashing icons and an audible beep indicate when batteries need replacement.
Setup and Installation
Important: Before beginning installation, ensure the power to your heating/cooling system is turned off at the main circuit breaker. It is recommended that installation be performed by a qualified technician.
Mounting the Thermostat
- Carefully detach the thermostat faceplate from its base.
- Position the thermostat base on the wall at an appropriate location, typically 1.5 meters (5 feet) above the floor, away from direct sunlight, drafts, or heat sources.
- Mark the mounting screw locations through the holes in the base.
- Drill pilot holes if necessary and secure the base to the wall using appropriate screws.
- Connect the system wires to the designated terminals on the thermostat base. Refer to your system's wiring diagram for specific connections.
Battery Installation
The UPM THM303A thermostat requires two AA-size batteries for operation.
- Open the battery compartment, usually located on the back of the thermostat faceplate.
- Insert two fresh AA-size batteries, ensuring correct polarity (+/-).
- Close the battery compartment.
After battery installation and wiring, carefully reattach the thermostat faceplate to its mounted base. Restore power to your heating/cooling system.
Operating Instructions
Setting the Operating Mode
Use the "Mode" button or switch (if applicable) to select between operating modes:
- Heat: Activates the heating system to maintain the set temperature.
- Cool: Activates the cooling system to maintain the set temperature.
- Off: Turns off both heating and cooling systems.
Adjusting Temperature
The thermostat features UP/DOWN buttons (or similar controls) to adjust the desired temperature. Press the UP button to increase the temperature and the DOWN button to decrease it. The new set temperature will be displayed on the LCD.
Fan Control
The fan operation can typically be set to:
- Auto: The fan runs only when the heating or cooling system is actively operating.
- On: The fan runs continuously, regardless of whether the heating or cooling system is active.
Programming Schedules (5+1+1 Day)
The THM303A allows for advanced programming to optimize comfort and energy savings. You can set up to four distinct program periods for weekdays (Monday-Friday), Saturday, and Sunday.
- Access the programming menu by pressing the MENU button (or similar).
- Navigate through the programming options using the UP/DOWN buttons.
- Select the day group (Weekdays, Saturday, Sunday) you wish to program.
- Set the start time and desired temperature for each of the four program periods (e.g., Wake, Leave, Return, Sleep).
- Repeat for all desired day groups.
- Save your settings and exit the programming menu.
The pre-comfort recovery system will automatically adjust the start time of heating or cooling cycles to ensure your home reaches the programmed temperature by the scheduled time.
Maintenance
Battery Replacement
When the low battery indicator appears on the display (flashing icons and/or beep sound), replace the two AA-size batteries promptly.
- Turn off the power to your heating/cooling system at the circuit breaker for safety.
- Carefully remove the thermostat faceplate from its wall-mounted base.
- Open the battery compartment and remove the old batteries.
- Insert two new AA-size alkaline batteries, observing the correct polarity.
- Close the battery compartment and reattach the faceplate to the base.
- Restore power to your heating/cooling system.
Dispose of old batteries according to local regulations.
Cleaning
Clean the thermostat's exterior with a soft, damp cloth. Do not use abrasive cleaners or solvents.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Display is blank or dim. | Dead or low batteries. | Replace with fresh AA-size batteries. |
| Low battery notification (flashing icon/beep). | Batteries are running low. | Replace with fresh AA-size batteries as soon as possible. |
| System not responding to thermostat settings. | Incorrect wiring, power off to system, or system malfunction. | Check wiring connections. Ensure power to the HVAC system is on. Consult an HVAC technician if the issue persists. |
Specifications
| Feature | Detail |
|---|---|
| Model | THM303A |
| Voltage | 24-Millivolt / 24 Volts |
| Power Source | 2 x AA-size batteries |
| Number of Programs | 5+1+1 Day Programming with 4 periods per day |
| Temperature Display Range | 0°C – 55°C (32°F – 131°F) |
| Temperature Setting Range | 5°C – 35°C (41°F – 95°F) |
| Humidity Display Range | 20% to 95% |
| Humidity Setting Range | 20% to 70% |
| Storage Temperature Range | -20°C to 50°C (-4°F – 122°F) |
| Dimensions (H x W x D) | 102mm x 150mm x 35mm (Note: Based on product description, not conflicting specification entry) |
| Controller Type | Push Button |
| Special Feature | Programmable |
| Color | White |
| Specific Uses | Central Heating System, Central Cooling System |
| Energy Star Certified | Yes |
Warranty and Support
Warranty Information
The UPM THM303A Thermostat comes with a 4-year warranty against manufacturer's defects. Please retain your proof of purchase for warranty claims. For detailed terms and conditions, refer to the warranty card included with your product or contact UPM customer support.
Customer Support
For technical assistance, troubleshooting, or warranty inquiries, please contact UPM customer support. Contact information can typically be found on the product packaging or the official UPM website.
