Buzz
Learn effective methods to troubleshoot and fix your malfunctioning thermostat
If your thermostat stops functioning, it can lead to discomfort in your home. Thankfully, many thermostat issues can be resolved easily. This Mytour guide will provide you with solutions for addressing a non-working thermostat, offering simple troubleshooting techniques and do-it-yourself solutions. We'll also advise you on when it's best to seek professional assistance.
Key Points to Consider
- If the screen is off or unresponsive, try changing the batteries and inspect the circuit breakers.
- Ensure that both the furnace and air conditioner are activated, and that the thermostat is correctly connected to your HVAC system.
- Resetting your thermostat can resolve programming issues and synchronize it with your HVAC setup.
Steps to Follow
Replace the Battery.
Is the display not working? Many thermostats rely on batteries for power. If your thermostat display is inactive, replacing the battery is often the solution. Most thermostats use 1 or 2 AA or AAA batteries.
- To access the battery compartment, remove the thermostat's cover.
- For certain models, you may need to detach the unit from its wall mount. To do so, gently lift the bottom of the thermostat and pull it away from the wall.
- Most battery compartments can be opened without tools, but some may require a standard Philips head screwdriver.
Check for Tripped Circuits.
Inspect your circuit breakers. If the circuit powering your HVAC system has tripped, your thermostat display may be functional but your HVAC system won't operate. If the circuit connected to your thermostat's wall is tripped and your thermostat isn't battery-powered, its display will also be off.
- Locate your home's breaker box, typically found in the garage or basement, and locate the breakers for your thermostat, furnace, and air conditioning (if applicable).
- If any breakers are switched off, toggle them off and on again.
- If your thermostat uses a C wire, common with smart thermostats like Google Nest, ensure it's supplying power. Before inspecting the C wire, turn off your home's main power breaker to prevent electrical accidents. Then, remove the cover and verify a wire is connected to the 'C' terminal.
Incorrect Programming.
If your thermostat settings are incorrect, it won't activate. Incorrect settings can lead to heating or cooling at the wrong times, failure to turn on when needed, or constant changes in settings due to programmed schedules. Ensure your thermostat is set to a temperature that triggers your furnace or air conditioner.
- To override a set schedule, select a temperature and press the 'Hold' button.
- Alternatively, restore your thermostat to its original program by pressing the Run or Run program button.
The HVAC system may be inactive.
Verify the power switch status for your furnace or AC. If either system is switched off, they won't activate regardless of thermostat programming. The furnace's power switch is typically located on its side, though a wall-mounted switch may also control it.
- If your furnace features a pilot light, ensure it's lit and the sensor is clean. If the pilot light is out and you're uncomfortable relighting it, seek assistance from an HVAC technician.
- Inspect the furnace fuse housed in a metal casing near the power switch. Replace any burnt fuses, but if the issue persists, contact an HVAC technician to prevent further complications.
Wiring issues may be present.
Ensure the thermostat wires match the manual's diagram. If your recently installed thermostat is malfunctioning, it may be wired incorrectly. Turn off the thermostat breaker (or the home's power if using a C wire), then cross-check the manual to verify correct wire connections and secure fastening.
- Clean the wires and terminals with a soft brush, lint-free cloth, or compressed air to remove dust.
- To access the wires, remove the thermostat's faceplate or lift it away from the wall plate.
Ensure Your Thermostat is Level.
An uneven thermostat can affect temperature accuracy. If your thermostat relies on a mercury bulb for temperature sensing, it must be perfectly level on the wall. Even a slight tilt can lead to a degree of temperature discrepancy for each degree of misalignment.
Consider Resetting Your Thermostat.
Resetting your thermostat can resolve various issues. If your thermostat appears out of sync with your HVAC system, a simple reset often restores functionality. Note that resetting the thermostat will erase any programmed settings.
- If your thermostat has a designated Reset button, press and hold it for approximately 5 seconds to initiate the reset process.
- For thermostats powered by batteries, remove them for about a minute after detaching the faceplate (or lifting the thermostat from the wall plate). If necessary, try reinserting the batteries incorrectly for a short duration before returning them to the correct position.
- For digital thermostats without batteries, flip the breaker to perform the reset.
- Smart thermostats usually offer a reset option within the Settings menu.
Check the Thermostat Placement.
Ensure Proper Temperature Sensing. If your thermostat is positioned near air vents, windows, doors, heat-emitting appliances, or receives excessive sunlight, it may inaccurately gauge the room temperature. Consequently, even if set to activate at 65 degrees, it may erroneously perceive a warmer environment, preventing the furnace from triggering.
Check Airflow Issues.
Address Short-Cycling HVAC Systems. If your furnace starts but shuts off prematurely:
- Regularly replace air filters to prevent overheating, typically every 60 to 90 days.
- Ensure all air vents remain open to prevent heat buildup, even in unused rooms.
Verify Gas Line Status.
Confirm Gas Availability. A gas-powered furnace requires an active gas supply. If the furnace fails to operate despite correct thermostat settings:
- Ensure the furnace's gas valve is switched to the On position.
- Check other gas-powered appliances' functionality to determine if the issue lies with the natural gas service.
A More Severe Issue May Be Present.
Larger Problems with Your Thermostat, Furnace, or Air Conditioner. If these components remain dysfunctional, consulting a certified HVAC professional is imperative. They can diagnose complex issues such as faulty thermostat control boards or wiring problems.
- Consider replacing an aging thermostat, as it may have reached the end of its lifespan. Numerous cost-effective options are available, including smart thermostats that enhance energy efficiency.
