Furnace Will Not Turn On With Thermostat

image of homeowner adjusting thermostat due to furnace will not turn on with thermostat

The chill of winter often pushes individuals to seek warmth, leading them to their home’s thermostat. A simple press of some buttons should activate the furnace, initiating a heat cycle. Shortly, the house should be enveloped in comforting warmth, a system trusted by countless families. Yet, this expectation is sometimes met with disappointment when the furnace fails to respond, such as a furnace will not turn on with thermostat. Naturally, this causes concern and unease during the colder months. In this article, we’ll explore the reasons behind such issues and the solutions available.

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My Furnace Won’t Turn On With The Thermostat

Regular upkeep is key to avoiding the unexpected inconvenience of a furnace that won’t start with the thermostat. Arrange for an annual inspection by skilled HVAC specialists, ideally in the fall, to prepare the furnace for the demands of winter. These experts will thoroughly evaluate the system, identifying any indications of deterioration, impending malfunctions, safety risks, or excessive accumulation of dirt. Addressing these issues promptly ensures that the furnace operates effectively. If you haven’t had a professional service check and find your heating system unresponsive, the cause could be one of several factors below:

Thermostat Problems

image of a homeowner feeling chilly due to furnace problems at home

The thermostat serves as the central control unit for your heating system, making it the first point of examination when troubleshooting. If it’s not effectively communicating your commands to the furnace, the issue may lie within the thermostat itself. There are several ways in which a thermostat can fail to perform as expected.

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Thermostat Settings 

Ensuring your heating system operates as intended often starts with a review of the thermostat settings. The settings could be the culprit if your furnace isn’t behaving as expected. A common oversight is the thermostat being set to ‘COOL’ or ‘OFF’ when you need heating. To activate the furnace, switch the setting to ‘HEAT.’ The temperature setting is also crucial; it might be set too low to make a noticeable difference in your home’s warmth. Try increasing the temperature by five to ten degrees and observe if this adjustment prompts the furnace to start.

Power Issues with Your Thermostat

close-up of thermostat wiring

After confirming that your thermostat settings are correct, the next step is to assess its power source. A common issue is a depleted battery in the thermostat. Simply replacing it with a new one could quickly resolve the problem, possibly turning the furnace on immediately. If this doesn’t work, the issue might be more complex, such as a malfunction in the power circuit. In such cases, it’s best to consult professional technicians who can accurately diagnose and recommend solutions. 

Thermostat-Furnace Compatibility 

Thermostats vary in type and are designed to be compatible with specific heating systems. If the installed thermostat doesn’t align with your furnace’s capabilities and capacity, it can lead to less-than-ideal performance or even miscommunications between the two. These mismatches can result in frequent operational failures. To avoid such issues, conduct thorough research before purchasing a thermostat or seek advice from an expert HVAC professional.

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Furnace Wiring Issues

Your heating system’s functionality hinges on a complex network of wires that transmit command signals and power. The efficiency of your heating system relies heavily on the integrity of its internal wiring. Over time, these wires can become loose, frayed, or otherwise damaged, potentially disrupting the connection between the thermostat and the furnace. This is a prevalent issue and warrants regular inspection. Homeowners with a good understanding of electrical systems should conduct an annual check of their furnace wiring. Alternatively, hire professional technicians for this task. 

Clogged Air Filters

Air filters are vital in maintaining indoor air quality and extending the lifespan of your heating system. These filters trap dirt and debris, but they have a capacity limit. When this limit is reached, and airflow is significantly hindered, replace the clogged air filter to maintain system efficiency. Neglecting this can lead to a substantial drop in performance, and the furnace might even shut down due to the increased strain. Monthly checks are recommended to assess the state of the filters. Replace them as needed for optimal furnace operation. Keeping a stock of compatible filters simplifies this maintenance task. 

Tripped Circuit Breakers 

While furnaces may operate on gas, propane, or heating oil, certain components depend on electricity for function. The circuit breaker safeguards the system against power surges and other electrical irregularities. If your heater unexpectedly ceases to work, the circuit breaker could be the reason. Inspect all breakers linked to the heating system to ensure they function correctly. Additionally, locate and examine the furnace switch. Sometimes, accidental bumps or movements can switch it off. If you find it in the wrong position, simply reset it to the appropriate setting and attempt to restart the furnace. 

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Furnace Belt or Blower Issues

Sometimes, a furnace may be operational, but specific problems can create the illusion of a more severe malfunction. A common example is a noticeable, high-pitched noise originating from the blower. This issue could be as simple as needing new lubrication or replacing a worn belt. In some instances, it may necessitate a complete blower replacement. Professional technicians should address such situations to guarantee a durable and efficient resolution.

Furnace Drain Pan

HVAC systems help reduce indoor humidity by extracting moisture from the air and collecting it in a drain pan, automatically expelling it. If a clog forms in this drainage path or the water pump fails, it can hinder the flow, causing water to accumulate in the pan. This accumulation might trigger a float switch, preventing the furnace from turning on. To rectify this, it’s crucial to empty the drain pan and confirm that the water pump is functioning correctly.

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Furnace Pilot Light 

image of furnace flames depicting furnace pilot light goes out after heating

A functioning pilot light is essential for many heating systems, as its absence can prevent the furnace from igniting. The pilot light may go out due to drafts, tripped safety mechanisms, or other system issues. Refer to your furnace’s manual for specific instructions to relight the pilot light. The general steps involve removing the access panel to locate the pilot light assembly. Then, turn off the reset switch and wait for about 10 minutes. After this, turn the switch to ‘PILOT’ to allow fuel flow, and use a match to relight it. If the pilot light continues to fail, seek assistance from a professional HVAC technician. 

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Furnace Fuel Levels

image of an outdoor home heating oil tank

No matter how well-maintained the other components are, the furnace can’t generate heat without sufficient fuel. Check the gas or oil supply to ensure there’s an adequate amount available for the system to function correctly.

  • Heating Oil Tank or Propane Tank is Out of Fuel: Heating oil and propane are stored in tanks. Monitoring these tanks and calling your fuel delivery company for a refill before levels drop too low is essential. Understanding your usage patterns helps in estimating when a refill is needed. 
  • Issues with Natural Gas Supply: Check other appliances using the same fuel source, like stoves or water heaters, to confirm whether they work. If there’s a disruption in natural gas supply, contact your fuel provider for help.
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Thermostats should seamlessly control heating systems. However, if your furnace remains unresponsive despite your efforts, refer to the troubleshooting steps outlined above to diagnose the issue. Alternatively, consider enlisting the assistance of professional HVAC technicians. Their expertise can help expedite the resolution process, providing a clear understanding of the problem and a swift return to normal heating operations.

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Miller Oil Company is the top provider of heating and cooling services in the greater Enfield, Connecticut area. Our team of certified technicians specializes in HVAC tune-ups, repairs, installations, replacements, and more. We always ensure that your system is serviced correctly. As the most popular HVAC service provider, we’re always ready to serve you!

We provide the most affordable heating and cooling services in the area. Our name stands for quality service and affordability. With our maintenance services, you can improve comfort and energy efficiency while lowering your home heating and cooling costs. Our team can recommend the most suitable HVAC solution for your home or business, keeping your budget in mind. All our work comes with a satisfaction guarantee. Contact Miller Oil Company today to schedule a service appointment. Call now!

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