The last thing that anyone wants or needs is an HVAC system that will fail when they need it most. But, even if the heating and cooling system is working as intended, there are some key components that will make the home feel too cold or warm. One of the most underrated parts of an HVAC system is the furnace motor blower. Without this key component, the treated air (hot or cold) cannot be delivered throughout the home. In this article, we will take a closer look at the importance of this part and five warning signs that it needs to be replaced.
What is a Furnace Blower Motor?
The furnace blower motor drives a fan that pushes the treated air through the air ducts to the vents. There are two types of motor blowers: belt drive and direct drive.
The belt drive furnace blower motors are less common in modern homes, but some models can still be found in older HVAC systems. A motor pulley on the unit is connected to a fan pulley, and the shaft turns a blower wheel. This technology can still be found in relatively modern commercial heating and cooling systems.
The direct drive motors are connected to the furnace blower wheel directly. This is the default technology for modern HVAC systems, and most gas furnaces use direct drive motors.
Residential furnace blower motors have two main speed settings: single speed and variable speed motors.
A single speed blower motor can only blow air at one high speed until the temperature that you’ve set on the thermostat is reached. As soon as the room temperature deviates from the set range too far, the blower motor unit will turn back on.
A variable speed blower motor can operate at different speeds. The main advantage of this type of motor is that it’s a more energy efficient option. The motor can keep the internal temperatures more even, and slight deviations out of the desired range require a slight compensation. If the temperature gap grows too large and too quickly, the variable speed blower motor can operate at a higher speed until the disparity is corrected.
5 Furnace Motor Blower Warnings Explained
Here are five sure-fire indicators that the furnace blower motor needs a repair or replacement:
1. Weak Airflow
If you place your hand over the vents and the airflow is very weak, this is a sure sign that there is a problem. The cause may be leaky air ducts, but in many cases, the core issue is related to the blower motor. The component may be failing due to advanced age in older HVAC systems, or it may be clogged with dirt and dust, which inhibits proper functionality. If the problem is a bad capacitor in the blower motor, it may be possible to fix the part to get the system running again. If the problem has persisted for a while, the problem may be an overheating issue, and the accumulated damage may necessitate a replacement. A local HVAC specialist can evaluate the condition of the blower motor and offer advice on the best way to fix the problem.
2. Rising Energy Costs
The blower motor unit is the highest consumer of energy in the entire HVAC system. This is true even if you’ve invested in a variable speed blower motor, which is more energy efficient. The energy efficiency can degrade if the blower motor is clogged with dust and debris. But, when the motor is reaching the end of its useful lifespan, it will need to work harder to push the treated air through the ducts. When components work harder, they are more prone to failure, and they consume more energy. Another possible cause of sharply rising energy costs is improperly installed or leaky ductwork.
3. Strange Noises
A problem with the blower motor unit or the connected fan is often accompanied by strange noises. If you can hear rattling, clanking, screeching, or squealing sounds when the HVAC system is running, you need to contact your local heating and cooling specialist. These sounds in a direct drive motor are usually an indication that there are bearing problems. In an older belt drive component, the sounds could be a belt break or slippage, much like the sounds from a car engine with fan belt issues. Banging, knocking, or rattling sounds may indicate broken parts that are loose and moving around. Loose parts can cause further damage to nearby components, and this will drive up the repair. So, if you hear strange noises, turn off the system and get an HVAC technician to investigate the cause.
4. Strange Odors
If you can detect a burning odor from the vents when the HVAC system is running, the problem could be an overheating blower motor. If the motor is prone to overheating, you may notice that it stops when you run the heat, or the system may shut down entirely. The HVAC system has built-in safety systems to protect your home from electrical damage, and until the core issue is fixed, they will continue to operate.
5. No Airflow
If you cannot detect any air coming from the vents when the HVAC system is running, this is a major problem. There is no point in running the system because the treated air cannot be distributed throughout the home. In this scenario, it’s likely that the blower motor has failed, and a replacement may be necessary. But, there are other possible causes to investigate first; a faulty thermostat, a fan control issue, or a bad relay can all prevent the blower motor from working properly.
A modern HVAC system represents a significant investment, it’s complex, and it requires regular maintenance to work at optimal efficiency. The system has electrical, electronic, and mechanical parts that work hard to keep your home comfortable. Just like any hard working components, these parts are subject to wear and tear over time. Early identification of potential problems during regular annual maintenance can prevent interruptions in heating or cooling.
If you suspect that you have a problem with your HVAC system motor blower or you want to schedule some essential maintenance, contact your local heating and cooling specialist today.