A failing HVAC system is the last thing you want when temperatures begin to rise in California. If your air conditioner isn’t providing cool air or is acting unusual, the best thing to do is identify and repair the problem as soon as possible. This way, your home can return to its comfortable state quickly. Many factors can cause an HVAC unit to malfunction, and sometimes the fixes are easy. Other times, there might be a more severe issue, like a broken component that needs to be replaced. The blower motor is an important component of your air conditioner, and it needs to be in top-notch condition so as not to affect the comfort level and air quality of your home. Here’s a comprehensive list of 5 signs your HVAC blower motor needs to be replaced.
First, let’s talk about what a blower motor does. The blower motor is a component in your HVAC system that blows the conditioned air through the vents in your home. It takes the cool air that your air conditioner makes and circulates it throughout your house. The blower circulates the air to ensure that the temperature reaches the level dictated by your thermostat. The blower is a spinning fan with a resistor that controls the fan’s speed and moves air through the ducts and vents in your home. Even a small motor can move large volumes of conditioned air.
There are two types of blower motors: a single-speed motor and a variable-speed motor. A single-speed motor blows air at one speed and to full capacity whenever it’s on. It will turn on and off according to the settings on the thermostat. A variable-speed motor operates at more than one speed, allowing for temperature control and more even air distribution throughout your home. The variable-speed motor also allows for better energy efficiency.
If you begin to notice more and more things are wrong with your air conditioner and you’ve had it for a few years, the trouble is probably with the blower motor. Like any mechanical part, a blower motor becomes more susceptible to mechanical issues when used over time. Repairing the motor will work for a little while, but it’s better to replace the whole thing the first time it acts up. You should replace your blower motor when you notice the following signs:
The first indication that you have a faulty blower motor is when the airflow out of your air conditioner is weak. Weak airflow means that the furnace blower motor has difficulty pushing air through the ducts to reach your desired temperature. The weak airflow could be because of dirt and dust buildup in the motor, a bad capacitor, or a motor past proper functionality. It is best to have an HVAC professional evaluate the issue to know if the weak airflow is caused by the blower motor, dirty or leaky ducts, or a clogged filter. Once they establish if it is the blower motor, they can clean it, fix a bad capacitor, or replace the motor entirely.
No airflow could mean that a problem with the blower motor has resulted in the component becoming inoperable. An inoperable motor means you will have to replace it with a new one. But, the absence of airflow can also result from a bad relay or battery, a fan control problem, or a faulty thermostat. Again, the best way to determine the cause of the problem is to have a heating and cooling specialist inspect your system.
The blower motor is the component in your HVAC system that uses the most energy. An aging, problematic, dirty motor has to work extra hard to circulate conditioned air through your home, so that could be why you see a sudden spike in your utility bills. If your air conditioner is way past its prime or using a single-speed motor, replacing it with a current, variable speed model would be beneficial. The new motor will automatically adjust its energy usage while cooling your home appropriately. Energy isn’t wasted then, and it will reduce your energy bill.
Unusual sounds coming from your HVAC system usually mean a possible problem with the blower motor. Squealing or screeching noises mean the blower motor has a damaged belt or bearings problem. You can fix this by replacing the belt or lubricating the bearings. If a motor is making more of a rattling, clanking, or banging sound, there could be a loose or broken part somewhere. Loud banging sounds indicate something being damaged or disconnected and are especially problematic. You should turn the unit off and contact a professional immediately to replace the motor at this stage. Promptly fixing these issues prevents the motor or other surrounding components from breaking. A technician can inspect the blower motor thoroughly and tell you if a repair or replacement is better.
Several things could be causing your motor blower to overheat. Dirt and grime on the motor could be stopping it from venting, which can cause heat to build up over time. If your blower motor is old and worn out, it will have difficulty keeping your home cool. The strain to produce cold air will lead to overheating, breakdowns, and higher energy costs. A couple of signs let you know your blower motor is overheating. There could be a burning smell coming from the vents, or the air conditioner will shut itself off to prevent further damage. When this happens, immediately turn your unit off and contact an HVAC specialist to replace your blower motor.
Contacting an HVAC company to replace your blower motor will ensure that you find the correct replacement model and that it is installed properly. A specialist understands the motor’s parts that will help find the right replacement, including the type of drive, the diameter of the motor, its rotation direction, horsepower, voltage, speeds, and the size of the capacitor. They can point you to the correct cost-effective models that operate in various settings and provide you with a quote. You can then schedule a time for installation.
At Atlas HVAC Inc., we will thoroughly inspect your blower motor to determine if it needs replacing before any work. We will then help you pick the best replacement motor and install it into your unit for optimal air conditioning use. Our extensive experience, highly-trained technicians, and stellar track record ensure that you will be satisfied with our work when it is done. Contact us today at (877) 452-8527, or visit our website for a free quote and get started on your blower motor replacement today!
One of the most common downfalls of installed HVAC systems is their inability to distribute the correct amount of air to where it’s needed most. When systems are restrictive, or blowers aren’t powerful enough, the air simply doesn’t make it to where it needs to go. This issue commonly manifests in the form of comfort complaints. In addition, most systems suffer from low air flow, only delivering a fraction of what they should. This can also mean that the capacity of a system is much less than what it should be. If it’s only moving 75% of the air, it can only deliver, at best, 75% of the rated capacity. This means that it will run longer in order to satisfy the load, costing more in operating costs.
A good HVAC system begins with the selection of a good piece of equipment. The unit selected must have the ability to push the amount of air that your building needs. The blower, and its abilities, is of the utmost importance to the success of an HVAC system, as our ductwork sizing is largely dependent upon the specifications of the blower found within the furnace or fan coil unit.
There are two general types of blowers that you’ll see:
The difference between the two becomes obvious when looking at their airflow tables (see below).
[box type=”download” icon=”none” border=”full”]NOTE: Often times, an Operating-Range blower is called a “variable speed” blower, or sometimes an “ECM blower.” Be aware, however, that there are now Operating-Point blowers that are ECM motors. This is a good thing, because ECM motors are more efficient than their PSC counterparts. But, remember that all ECM blowers are NOT necessarily variable speed Operating-Range blowers.[/box]
The OP blower will have a decrease in airflow as static pressure increases. The OR blower, however, will maintain the same (or close to the same) airflow over a range of static pressure. It achieves this by adjusting its rotating speed to “match” the resistance it has to work against.
The static pressure shouldn’t actually change that much after your system is installed. (As filters get dirty, their static drop will increase. The amount of increase will vary depending on how much air you’re trying to move through the filter. This is why it’s a good idea to oversize filters.) So, don’t get the wrong idea from my statement above, “as static pressure increases.” Part of the HVAC design process involves the selection of the static pressure at which the design will be based. The idea here is that we select the destination point, or “design static,” and then design our system so we arrive on target.
That said, you’ll notice that there are more static pressure options from which to choose if you’re using an OR blower. It’s also important to understand that an operating-range blower has to consume more energy to rotate faster in order to overcome the additional static pressure. There is a price to pay, so to speak, for achieving your desired airflow at a high static pressure.
When using an operating-point (OP) blower, your budget is etched in stone. You have one static pressure option, per blower speed setting, that corresponds to one airflow quantity. When you overspend your OP static budget, your airflow decreases, along with capacity, efficiency, and durability. So, the OP blower ASP selection process is dictated by the quantity of airflow you need, along with the blower speed you choose to design with.
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This chart shows the blower details for a 1.5-ton fan-coil unit. Notice that there are 5 different speed settings: 1-5. If our goal was to have 600cfm moving through the system, we would have only two operating-point options. The first option would be to set the blower speed to Med High #4, and design the duct system to create a total external static pressure (TESP) of approximately 0.65 IWC. This would allow our blower to move the 600 cfm we need (interpolate between the 0.60 and 0.70 columns). The other option would be to set the blower on the High #5 speed setting, while creating a TESP that is off this chart – probably somewhere in the 1+ range. Since the data isn’t listed, this would be a risky route to take. So, we’d be left with only one option. Our available static would be 0.65 IWC.[/box]
When using an operating-range blower, the ASP selection process is a little different. You actually get to select it from the range of static pressures listed on the blower’s airflow chart. You’ll see that there’s a limit to the OR blower’s ability to fight against high static pressure. At some point, typically around 0.75 IWC (inches of water column), the airflow will begin to drop off, which may be below your desired airflow.
Manual-D recommends that you stay away from the “top-third” of a blower’s ASP range listed by the manufacturer. My real world recommendation is to choose the lowest ASP that you possibly can, typically between 0.50-0.75 IWC. After you lay out the ducts, fittings, and components, you can adjust your ASP until your FR is within the acceptable range.
Sometimes, you’ll find that you may need to use a larger piece of machinery in order to find a blower that is strong enough for your needs. I frequently run into this when trying to use small furnaces (40kbtu) that have large cooling loads (2.5 tons, for instance). It is difficult to find a 40kbtu furnace that can move 1000 cfm at a reasonably high static.
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This chart shows the blower details for a 120,000btu furnace. This unit has a variable speed motor that operates in an operating-range configuration. For each combination of ON/OFF switching displayed, the blower will deliver a different amount of airflow based on the TESP listed at the top of the chart.
If we had a 3-ton air conditioner attached to this system, we would want to deliver about 1200cfm of air through the system. We would select the ON, OFF, OFF option, combined with the SW4-3 option shown in the footnote. This would enable us to deliver an airflow quantity just shy of 1200cfm. When choosing the ASP for our Friction Rate calculation, we’d be able to choose any of the static pressures shown, as long as the associated airflow would meet your system’s needs, since the blower will adjust its speed accordingly. The thing you must keep in mind is that high static = high energy use, because the blower is working harder. This may also decrease the blower’s life expectancy. My suggestion is that you start off with 0.50 IWC, adjusting upward as needed until your Friction Rate is within the appropriate range.
Many manufacturers will offer a couple different models of the same capacity (when dealing with furnaces), each of which have progressively stronger blowers. This allows them to be paired with larger-sized air conditioners, which require larger airflows.[/box]