Your forced-air furnace can operate reliably for many years with proper ongoing maintenance. However, when these systems break down, it can be highly inconvenient. Breakdowns typically occur during winter, when your furnace is running and your household relies on the unit to keep your indoor temperature at a comfortable level.

What to do if your furnace stops working in the winter? Fortunately, some furnace issues are relatively easy to troubleshoot and repair yourself. In this guide, our team at Leith Heating & Cooling, Barrington IL’s furnace repair experts, discusses some of the steps you can take yourself if you have a broken furnace.

Safety First: Check for Leaking Gas

A gas leak can develop in your furnace or the gas lines that lead to the furnace. While this issue may not cause your furnace to stop working immediately, addressing a gas leak is critical to ensure your household members’ safety.

Signs that your furnace has a gas leak include:

  • Hissing sounds, even if your furnace is off
  • A rotten egg odor inside your house
  • Flu-like symptoms resulting from gas inhalation
  • Dying house plants

If you suspect your furnace has a gas leak, get all household members and pets out of the house, and leave the door open to ensure proper ventilation. Don’t use firelighters or matches, and don’t turn any electrical switches on or off.

Locate your home’s supply gas valve near your gas meter and inlet pipe, then switch it off. Once your gas supply is off, schedule an emergency repair service.

1.  Check Your Circuit Breaker

A sudden furnace shutdown may be due to a power interruption. If the unit stops working, open the breaker panel and locate the furnace’s circuit breaker. If this circuit breaker has tripped, it will be in the “off” position.

Before resetting the furnace’s circuit breaker, turn the thermostat to the lowest setting so that the unit doesn’t start up the moment you reset the breaker. Next, switch on the circuit breaker. If the circuit breaker tripped for no reason, your furnace should be operating normally.

However, if the circuit breaker trips again shortly after you reset it, your furnace may have another problem. Issues that may cause a circuit breaker to keep tripping include:

  • A bad circuit breaker
  • A faulty capacitor
  • A furnace wiring short

In some cases, a clogged furnace filter can increase the load on your furnace motor. Replacing this filter may resolve the problem. However, if your filter is still relatively new and clean, you need professional furnace repairs.

2.  Make Sure the Thermostat Is Working

A thermostat malfunction or setting can cause your furnace to stop running. If the shutdown is not due to a power interruption, check the automatic clock of your programmable thermostat. You may find that the clock scheduled your furnace to switch off, in which case you only need to reset the clock.

The problem may be due to dead batteries if you have a modern programmable thermostat. Replacing these batteries may restore your furnace to regular operation.

A loose thermostat wire connection can also cause a furnace to stop working. Loosen the thermostat’s casing and pull it carefully from the wall. You will see two to six low-voltage wires that connect the thermostat to the furnace.

Each wire should connect securely to a corresponding thermostat terminal, and a loose connection is likely the cause of the shutdown.

A faulty transformer can sometimes cause a furnace to stop working. This component regulates the currents and steps down the voltage so that it is suitable for use by the thermostat. You likely have a bad transformer if there are burn marks along the furnace exterior or if the unit vibrates or hums.

If you treat a transformer replacement as a DIY project, you may damage your system. Schedule a professional repair if you believe the shutdown is due to a transformer issue.

3.  Inspect the Condensate Pump

When researching what to do if your furnace stops working in the winter, you will inevitably encounter information on condensate pump inspections and drain line blockages. These issues are relatively common, and you can take care of them yourself.

A furnace’s heat exchange process produces condensation. A gravity drain tube removes the excess water if your home has a drain on the floor nearby.

However, suppose your home’s drain is in another location. In this case, a condensate pump moves the water from the built-in reservoir to the drain.

If the condensate pump breaks down and the reservoir fills up to a specific level, a safety mechanism will shut the furnace down to prevent flooding in your home.

Replacing a furnace’s condensate pump is relatively easy. However, if you are not an avid DIYer, it’s best to schedule a professional furnace repair service.

4.  Check the Pilot Light and Thermocouple

Let’s say you have an older furnace that uses a pilot light. In this case, if your furnace stops working, your pilot light may have gone out. To restart your pilot light, follow the steps below:

  1. Shut down your gas valve and wait ten minutes for the gas to dissipate
  2. Switch the gas valve to “Pilot”
  3. Push and hold down the knob that releases the gas flow
  4. Light the pilot using an extended lighter without releasing the knob
  5. Release the gas knob slowly once the pilot light is on
  6. Switch the gas valve to “On”

If the pilot light keeps going out, the furnace may have a loose thermocouple, a pilot orifice blockage, or a faulty safety cut-off valve. Scheduling a professional furnace repair service may be necessary to restore the pilot light function.

Get In Touch With Us

Knowing what to do if a furnace stops working in the winter means you don’t need to rely on more expensive heat sources, such as space heaters, to keep your home warm. Ideally, you should prepare your furnace for the winter to ensure that it operates reliably with no issues. If you encounter a furnace issue, contact our team at Leith Heating & Cooling in Elgin, IL, to schedule a professional repair.

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