Thermostat Not Turning On Heat? Here’s What You Need To Check

Is that old thermostat not turning on heat when you need it to kick into action? Ohio winters can be brutal, with snowy weather and freezing temperatures. Having functional and fully responsive heating isn’t negotiable here, so when you turn your thermostat to “Heat” mode and your house stays chilly, don’t ignore the problem.

A1 Mechanical Heating & Cooling is a top-rated company providing heating and air repair in Dayton, Ohio. As locals, we know how frustrating it can be to want the cozy warmth of a functional heater and find only a faulty thermostat instead. Read on for some heating system tips we’ve learned along the way.

Reasons Your Thermostat Might Not Trigger a Furnace or Heat Pump’s Operations

Your thermostat could fail to trigger your HVAC for several reasons, including the following:

Failing Temperature Sensors

Dirt isn’t the only problem temperature sensors face. Typically, these components have five to ten-year lifespans and could sustain damage. If HVAC thermostats malfunction due to being broken or too old, they’ll misread temperatures.

Incorrect Thermostat Settings

Are you sure your thermostat is in “Heat” mode with the correct programming and temperature setting? If you find the thermostat not turning on heat, incorrect settings are a real possibility. 

Adjust the device via these steps to ensure accuracy:

1. Ensure the heat setting is on.
2. Turn the fan to “Auto” (not “On”).
3. Adjust the temperature at least one degree higher than room temperature (not too high for the furnace to reach – it’s just a test run).

Sometimes, slightly raising the temperature gets your heating system going, but never increase it more than five degrees above room temperature. Drastic differences between outdoor and indoor temperatures and thermostat settings can be problematic. 

Wrong Thermostat Placement

It’s not uncommon for people to install thermostats in the wrong spot in their buildings. Placements too close to the kitchen, a fireplace, or a window with direct sunlight could trick its sensors into thinking the house is warmer than it actually is. With an incorrect sensor reading, the thermostat might fail to turn on the heat, leaving you cold and uncomfortable. 

It’s always best to install a thermostat in the middle of the house, away from heat sources or cold drafts to ensure accurate readings. Place it about five feet above the floor for the same reason.

Device Miscalibration

Is your thermostat an older model? Could its problems simply stem from miscalibration? This misalignment shows the device’s temperature doesn’t match a building’s actual temperature, and it’s quite common.

To test thermostat calibration, tape a mercury-based thermometer to the wall, about an inch away from your thermostat. If both readings differ by more than two degrees after a 15-minute wait, your device needs recalibration. Before calling an HVAC technician, you can also clean it off and test it again to ensure debris buildup isn’t causing a false reading.

Lack of Power

Is your thermostat not turning on heat? It could have dying batteries. This lack of power will cause the equipment to turn the furnace off and on at the wrong times. 

If the settings are correct but the furnace or heat pump isn’t generating heat, change the thermostat’s batteries to restore energy supply. If the equipment doesn’t run on batteries, the same concept applies as it could still have power supply issues. In a hardwired thermostat, conduct a circuit breaker check instead.

Dirty Components

A final reason for a faulty thermostat temperature reading might be an obvious one: dirt accumulation.

Dust, dirt, and other debris can settle in and around older thermostats and affect temperature sensors. Gently clean your thermostat with a soft-bristled brush or cloth periodically. Dirty thermostats often have false temperature readings, which can keep your heater from turning on.

Why Your Heater Isn’t Working With a Functional Thermostat

Sometimes, your otherwise healthy thermostat not turning on heat has nothing to do with the device itself. For instance, the greater heating system could be experiencing these issues:

Inadequate HVAC Power Supply

No furnace or heat pump can function without an adequate, reliable power supply – and that includes HVACs that run on gas. Since furnace power switches resemble light switches, anybody can mistakenly hit the HVAC unit’s power switch and render it useless. 

Check your equipment to ensure the switch is in the “On” position. Then, check your circuit panel to see whether the heater has tripped the breaker due to an influx of electrical current. Flipping a tripped breaker back on may restore the heating system’s operations. 

Filthy Air Filter

Furnace filter blockages pose a major issue that many people overlook. These filters trap airborne contaminants from the air flowing through the HVAC unit. Unfortunately, air filters aren’t self-cleaning, so they’ll eventually clog and restrict airflow unless you replace them. 

Insufficient airflow will cause the HVAC system to overwork itself, overheat, and then trigger the furnace’s safety sensors, forcing a shutdown.

Dirty Flame Sensor

Furnace flame sensors are safety features that measure how well the gas burners ignite once the gas valve opens. If the valve opens without a strong flame to ignite the gas, the sensor will shut the furnace down to prevent the gas from building up inside the heater and seeping out. 

Too much soot, dirt, and carbon deposits also prevent the sensor from working correctly.

Loose Connections

Your thermostat controls your HVAC through several wires and connections. Visually inspect the wires and test the connection using a multimeter. 

See signs of corrosion, fraying, or looseness? These issues impede communication between both systems and need professional repairs.

Call Our Heating and Cooling Experts for Furnace, Heat Pump, or Thermostat Repairs

If you find your HVAC not heating or your thermostat not turning on heat, A1 Mechanical Heating & Cooling‘s skilled technicians have decades of combined experience and extensive training to help you out. Allow us to quickly identify furnace problems, fix malfunctioning thermostats, and handle heat pump troubleshooting – and always go above and beyond to restore your system’s performance!

Don’t settle for an inefficient HVAC unit—call A1 Mechanical Heating & Cooling today at (502) 708-2247 to request services in Dayton, Ohio.