There is no worse time to have an overheating furnace than during the winter. A furnace prone to overheating usually shuts down abruptly at odd moments. And successfully getting it started again is a game of chance, which may leave you stranded in the chilly weather where HVAC professionals are busy.
To avoid getting into this situation, ensure that you have regular maintenance and repairs with a trusted professional, like one of the technicians at Anderson Air.
Homeowners often ignore the signs that a furnace gives out when it’s overheating. These signs include strange noises from the furnace unit, a burning smell, and the furnace irregularly turning off and on.
So let’s get to the main question — “why is my furnace overheating and turning off?”.
Your furnace is getting too old for your home
Most furnaces can live and operate for up to 20 years, provided that they get routine maintenance, checkups, and repairs (when required).
As a furnace draws towards its maximum age, it becomes prone to overheating and shutting down. All the repair work you do on it is merely patchwork. To enjoy the heating efficiency and reliability of a furnace system, buy and install a new furnace.
There are blocked and dirty ventilation systems
Although closing some vents can regulate the temperature in different rooms of the house, closing too many vents blocks heat transfer from room to room. And once the furnace doesn’t transfer the heat elsewhere, there is heat or pressure buildup, causing the furnace to overheat and shut down.
Also, when debris accumulates in the vents, it obstructs the passage of warm air, causing pressure buildup, overheating, and potentially shut down the furnace.
You can prevent this by unblocking or reopening the air vents and setting the thermostat to lower temperatures.
Faulty components of the furnace unit
Are you still wondering what causes the furnace overheating and shutting down process?
Mechanical failure can also lead to overheating. A furnace is made up of different small parts and wiring. So, if any of its internal components, like the fan blower, gets damaged or becomes faulty, the furnace can shut down.
To find out the cause of the furnace abruptly shutting down, contact a professional HVAC technician to inspect and repair the furnace.
Poor furnace maintenance
Electrical and mechanical devices need prompt and regular maintenance to keep in top working condition. On the other hand, irregular maintenance and inspections leave room for problems to crop up, grow and distort the efficient operation of the furnace.
To prevent this, schedule regular maintenance check ups once or twice every year.
Your furnace filters are getting too dirty
“Why is my furnace overheating?”, you may be wondering.
Dirty furnace filters prevent sufficient airflow. Furnace filters are vulnerable to collecting dirt, lint, dander, and other filthy materials. When the debris levels increase, they block the filters, obstructing the efficient passage of air through the filters.
This makes the furnace exert more energy to suck in cool air and blow out warm air. And more energy expended leads to overheating. Continuous overheating makes the furnace shut down.
To ensure proper airflow, regularly inspect, clean, and replace the furnace filters.
Filthy internal components of your furnace unit
Apart from vents and air filters, other parts like the furnace coils also get dirty. When the coil becomes very dirty, it prevents the heat exchanger from transferring heat.
Also, a dirty blower motor cannot ventilate itself, leading to the furnace overheating.
Short cycling issues
Short cycling doesn’t only happen in air conditioners; it also occurs in furnaces. Furnace short cycling is when the furnace system shuts off before completing the heating cycle. These incomplete heating cycles prevent your room or home from warming up.
Why is my furnace overheating and shutting off? Short cycling may be the answer.
Short cycling usually happens when there is poor airflow or a problem with the heat exchanger. These issues distort the usual furnace operation, causing it to be controlled by the high-limit switch instead of the thermostat. And once the control device changes, it stresses out the furnace motors and other furnace components.
To prevent damage to its motors, the furnace prematurely turns itself off to cool off. Once it cools off a bit, the furnace turns back on, only to overheat again and shut off again. The repeat cycle of turning on and off can damage the system, causing the furnace to shut down.
The easiest way to notice short cycling is when your furnace system takes shorter periods of time from the moment it powers on to when it suddenly powers off.
Furnace short cycling can also be a result of another problem, like having a faulty thermostat and having a furnace that is too big for your house. That is why you should contact an HVAC specialist to pinpoint the exact cause of the issue.
The danger of an overheating furnace unit
It is very important to know why your furnace is overheating and shutting down. This knowledge will help you prevent or rectify the problem quickly. If you downplay or postpone repairing the problem, you could be putting the lives of people in your household at risk.
If you have a gas furnace, overheating allows this dangerous carbon monoxide to leak into your house, leading to health problems or death. This is because an overheating furnace develops stress cracks in its heat exchanger. And this increases your repair costs and may expose you to carbon monoxide poisoning.
Since leaking boilers and furnaces are among the leading causes of carbon monoxide poisoning in homes, it is imperative to install a carbon monoxide detector near your furnace and boiler so that you can get an early alarm/signal when the furnace heat exchanger becomes damaged.
Conclusion
When it comes to ensuring comfortable temperatures during freezing weather, guarding against carbon monoxide poisoning, and reducing repair costs, take no risks. Once your heater overheats, immediately check the furnace air filters and vents for airflow obstructions. If there is no issue with them, switch off your furnace and call up a professional HVAC technician/company.
