Charlotte Miller

Signs You May Need Furnace Repair

Conventional gas-powered furnaces are those with an annual fuel consumption efficiency (AFUE) of up to 89%. These are often older, non-condensing furnaces that vent exhaust gases through fireplace flues rather than PVC piping and might come with standing pilot lights.

As high-efficiency condensate furnaces featuring AFUE ratings approaching at least 90% gain popularity, certain troubleshooting methods must be used.

Mechanics of Forced-Air Furnaces

Whether traditional or high-efficiency, a forced-air gas furnace performs the following functions:

  • ingests chilly air.
  • uses an air filter to clean it.
  • heating it using a gas burner and a heat exchanger made of steel.
  • uses a blower motor to distribute the warm air throughout the ducting in your house.

Through returning air grilles and ductwork, the warm air then cools throughout your house before returning to the furnace. Another heating loop is completed when the chilly returning air enters the furnace through the air filter. On occasion, a humidifier is put on the heating system or the ductwork for the return air.

Conventional furnaces often have a straightforward design, but occasionally something will not function properly. Here are a handful of the typical issues with a traditional gas furnace across which you could run.

Recognizing the many types of gas furnaces and AFUE performance categories

Heat is absent or is insufficient.

It is crucial that the heating system is operating correctly and generating enough heat to keep your house comfortable when the winter weather arrives. Otherwise, furnace repairs could be necessary to get you through the winter.

There are a number of potential causes if the furnace stops providing heat or simply blows chilly air. Some repairs you could potentially be able to handle on your own, while others will need a professional. Simple solutions might be:

  • confirming that the heat vents are open.
  • the thermostat’s settings being examined.
  • confirming the furnace’s power

Frequent On/Off Cycles of the Furnace

By fixing a gas heater that is regularly cycling off and on, or “short cycling,” you may save energy expenses and protect your furnace. This practice could be typical and required in really chilly weather to maintain a pleasant temperature in your house. On the other hand, it can indicate a furnace issue.

Investigate many potential problems, such as a clogged exhaust vent, a filthy filter, or a broken thermostat.

Runs Blower Nonstop

There are two potential explanations to think about if the heating blower is always running:

The FAN setting on the thermostat is selected. The blower will operate continuously as a result of this. This could be preferable in a few circumstances, including when you wish to filter the atmosphere or dry out a damp residence.

But in most instances, it only causes the blower motor to deteriorate. The fan will only run when the appliance is heating or cooling, thus the remedy is to adjust the thermostat’s blower setting back to AUTO.

It is possible that the fan limit controller switch is broken. The fan limitation switch is a security device that keeps track of the furnace’s temperature and turns off the parts when predetermined temperatures are achieved. The limit switch may be broken if the blower operates continuously. Reset the airflow limit control switch to solve the issue. If it is broken, replace it instead.

A pile of old air conditioners

Description automatically generated

Noise from Furnace

Excessive furnace noise usually signals a developing issue that, if ignored, might cost you money to fix. A low-pitched buzzing, loud hammering, or high-pitched screeching might be heard.

While you can solve certain issues on your own, it may be more cost-effective in the future to hire a professional straight away. Replace the filter, since a blockage may be the source of the disturbances, and oil the blower motor as other easy fixes.

Out of Pilot Light

Strong drafts, a filthy aperture in the pilot’s burner, or debris in the gas tube can all cause the standing pilot flame to go out on older furnaces. Alternatively, a broken thermocouple might cause the gas supply to be cut off.

One of the most typical causes of a gas furnace not producing heat is the light on the pilot going out. Fortunately, it is not too difficult to relight your pilot’s light. And if the thermocouple breaks, replacing it is simple.

Mismatched Thermostat and Furnace

In order to operate properly, furnaces and controllers must be matched properly. The improper kind of thermostat paired with the heating system will result in operational issues.

For instance, despite how your thermostat is set, your furnace could overheat and underheat your house. Today’s thermostat systems come in three varieties: millivolt (, lower voltage, and voltage of the line. Ensure that the furnace-appropriate kind is installed.

Thermostat has a problem.

Some typical signs that your furnace displays may really be the result of a broken thermostat. Check the thermostat after you have ruled out the usual suspects with the heater itself, including a dirty filter.

Furnace issues might show up as a heating system that does not provide any heat, has dramatic temperature fluctuations, or cycles on and off frequently enough. Make sure your thermostat is powered on and that none of its parts are obstructed by dust or dirt. Consult a specialist if it is still not functioning.