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3 Warning Signs Your Gas Furnace's Inducer Motor Is About To Fail

28 April 2023

Abbie Wade

You probably understand what your HVAC system's house (or main) blower does. This large fan distributes hot and cold air throughout your home, helping to keep you warm in the winter and cool in the summer. However, your furnace contains another blower that's just as important: the draft inducer. This smaller fan is critical in keeping your furnace safe and efficient.

Since your draft inducer is so important, your furnace contains safety mechanisms to prevent it from running when the inducer fails. However, you don't need to wait until you lose heat to address a faulty inducer motor. If you notice one of these three symptoms, your inducer motor may require urgent attention.

1. Your Furnace Doesn't Start Immediately

This symptom may be hard to detect, but a furnace that struggles to start may be suffering from a draft inducer problem. The typical startup sequence for a natural gas furnace includes several safety checks, including a pressure check that ensures the correct operation of the inducer motor. If any of these checks fail, the furnace will not start, although most furnaces will try again a few more times.

When your draft inducer fails, it may not start immediately or produce enough negative pressure to trigger the draft sensor. In these cases, the furnace may run through its startup sequence several times before the draft inducer can finally satisfy the sensor. If you hear your furnace clicking on and off several times before finally lighting, a faulty draft inducer is one potential culprit.

2. You Can Hear Grinding, Rattling, or Clicking Before Your Furnace Ignites

The draft inducer pulls combustion gases through the combustion chamber and into the heat exchanger and exhaust flue. This process helps keep your furnace safe while increasing combustion efficiency by ensuring that only oxygen and gas are present in the combustion chamber. In other words, the inducer must start running before your furnace ignites to clear any old, unburnt gas from the burners.

Since the draft inducer is typically the first mechanical component to spin up in your furnace, you can usually easily hear any issues it may be having. If you hear a clicking, grinding, or rattling noise before your burners ignite, the source is probably the draft inducer. These noises can indicate a problem with the blower wheel or a mechanical issue with the motor. Either way, the draft inducer is likely in trouble.

3. You Receive a Pressure Switch Error

Error codes are one of the more convenient innovations in modern furnaces. Like your car, your furnace can display an error code when it detects a problem. These codes can often be cryptic (and may simply be a series of flashes from a single LED), so you'll need to consult your owner's manual to decode the problem.

Error codes relating to the pressure switch usually point to a problem with the draft inducer. If your furnace is still running, the error may mean that your draft inducer is weak and causing periodic pressure check failures. Note that these error codes can also indicate a problem with the pressure switch, so you should have a professional investigate instead of blindly replacing your draft inducer.

To have your unit inspected, contact a professional heating contractor in your area.

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