How To Change Blower Speed On Carrier Furnace

Changing the blower speed of your furnace is necessary to achieve the right temperature. If you have a Carrier furnace, its variable speed technology allows easy control for consistent comfort and energy efficiency. So, how do you change the blower speed of your furnace? We have researched answers for you.

Change the blower speed of a Carrier furnace by adjusting the pulley on the blower drive motor. Slightly loosen the setscrew and turn the pulley clockwise. A high blower speed decreases temperature while lowering the blower speed increases it. 

When changing the blower speed taps, you should always follow the warning of the electrical operation hazard. If you don't follow the precaution, you might get injuries. Keep reading to understand the blower settings of a Carrier furnace.

Steps on how to change blower speed on Carrier furnace, How To Change Blower Speed On Carrier Furnace

Adjusting Carrier Furnace Blower Speeds

You can change the blower speed of your Carrier furnace to regulate the temperature. Refer to the furnace rating plate if the machine's temperature is within range. If the air temperature is not within the range, a solution you can do is to adjust the blower speed. 

If you are reducing the temperature, increase the blower speed. When you want to increase the temperature, you decrease the blower speed.

Before you change the blower settings, you need to be familiar with the location of the blower motor. You will find the motor on the bottom cabinet of the furnace. To open the cabinet, the blower door switch only opens if you supply the machine with 115V power.

Once you find the motor, you will see 5-speed taps on the selection terminal. The taps have different colors corresponding to different speeds. You can set the speed before operating the unit. As a precaution, disconnect the power first before you change the speed taps. 

Hvac repair technician removing a blower motor from air handler

Based on the manual, there are the 5-speed tap colors and the corresponding components it connects. Gray has the highest speed of 5 with factory attached to COOL. Red has the lowest speed of 1, which connects to the LO HT fan.

In addition, the manual informs users to caution against unit damage. If setting up the furnace, you should never connect the RED and ORANGE speed taps to the HEAT factory on all furnace models.

If the wires connect to the heat component, the furnace will operate outside the temperature range. As a result, the connection causes component damage.

How To Change The Blower Speed

Below are the steps to adjust the blower speed of the furnace: 

  1. Adjust the pulley that you will find on the blower drive motor.
  2. You have to loosen the setscrew holding the pulley on the driveshaft.
  3. Then, turn the pulley clockwise if you are increasing the speed. Turn counterclockwise if decreasing the speed. If you want a higher speed, turn the pulley twice.
  4. After turning, tighten the setscrew. 

When Should I Change The Blower Speed On My Furnace?

There are different reasons for changing the blower speed. The common reasons are to increase or decrease the warm airflow and quiet down the furnace. 

It will help if you increase the speed to allow sufficient airflow inside the furnace. The increased airflow helps in dehumidifying and fixing register condensation problems. However, the increased speed consumes so much energy. So, you need to increase the speed to conserve energy gradually.

If you decrease the blower speed, you can make the furnace run quietly and remove more moisture. Also, it slows down the furnace's energy efficiency.

At What Speed Should A Carrier Furnace Blower Motor Run?

A Carrier furnace has variable speeds ranging from 300 to 1300 RPM if operating with a 24-VAC motor. The speed you should set depends on the current conditions inside your home. 

Modern homes with energy-efficient fixtures have tighter air envelopes and increased insulation levels. Hence, it becomes challenging to control the HVAC systems and align their functions to the changing conditions.

However, it is not a simple task to do. You have to consider the types of heat inside your home and the furnace itself. The components should work correctly so the furnace can continue controlling humidity and comfort at home. The normal cooling airflow of the furnace is 350/cubic feet per meter per ton. 

In light of this issue, mechanical sizing is a mandate from the IECC to achieve energy efficiency. The new Carrier blower motors are all FER-compliant ECM motors that reach 80-85% of electrical efficiency.  

You should adjust the dip switches to get the correct blower speed setting. Choosing the setting that controls humidity while optimizing the blower motor is best.

You can refer to the product manual and look for the cooling and heating air delivery table to make the changes.

How Do You Troubleshoot A Carrier Furnace Blower Motor?

Repair technician removing furnace service panel

If you encounter problems with the furnace because of the blower motor, there are available solutions you can do.

Follow the tips below on how to fix the problems of the blower motor:

1. No Power

Check if your furnace has power. There can be a loss of power due to a recent power outage, tripped circuit breaker, or a blown safety switch fuse. 

You can try turning on the furnace after an outage and see if the motor works again. If the cause is a tripped breaker, just flip it back to reset it. If the cause is a blown fuse, immediately replace it. 

2. Thermostat Setting Set Too Low

Setting the thermostat at the lowest temperature will not trigger the blower motor to operate. The thermostat should be at least 3-5 degrees above the current room temperature.

Besides the thermostat, check if the fan setting is on so the thermostat will also turn on. Like the furnace, check if there is power supplied to the thermostat.

3. Clean House Vents And Filters 

To avoid dust and debris buildup, keep the furnace house vents and filters clean. The accumulation of dirty particles might go to the motor components and block the airflow.

Aside from cleaning, the vents and filters should be in the right direction so the air circulates properly.

4. Examine The Blower Motor

If the furnace components are okay, it is time to inspect the blower motor. The belt of the furnace can be defective and needs replacement.

Fully close the furnace door to check the belt issue. You should replace a worn, frayed, or completely damaged belt. When installing the new belt, ensure it is in the correct position. 

Furthermore, dust, dirt, and debris will cause overheating of the motor. These will clog the motor holes, and the bearings and windings will burn more quickly. After further inspections, if the blower motor and fan assembly cannot move freely, add a few drops of oil and check if the motor works. 

You need a blower motor replacement if the old motor does not spin freely due to damage.

HVAC blower motor of an air handler

How Much Does It Cost To Replace Carrier Furnace Motor?

Depending on your model, a new Carrier furnace blower will cost around $500-1,200. If you let a technician replace the part, you can spend another $150 for labor. Check if your unit is within the 10-year warranty, so you don't have to worry about the cost.

What Are The Benefits Of A Variable Speed Technology?

Benefits of Variable Speed Technology, How To Change Blower Speed On Carrier Furnace

With the advancement of technology, heating and cooling systems have upgraded to give the best for users. Carrier has a variable speed technology that offers the following benefits:

  • Better air quality - You will have cleaner indoor air because the furnace is always on.
  • Consistent comfort - With continuous operation, the air temperature is close to the set thermostat temperature. As a result, there will be few cold or hot spots inside your home.
  • Improved humidity control - The prolonged furnace operation will keep you comfortable because you don't have to change the blower settings more often.
  • More energy savings - The furnace uses less electricity to run continuously at lower speeds.

With the benefits mentioned, you will feel more comfortable at home with a Carrier furnace. 

In Closing

You can adjust the blower speed of a Carrier furnace by adjusting the pulley and tightening the setscrews. Another way is to select the speed taps to the desired speed when setting up the furnace.  

Change the blower speed when you need to increase or decrease air temperature and quiet down the furnace. If changing the blower speed has issues, you should inspect the furnace parts. Replace a defective blower motor if there is no available solution to fix it.

Adjust the blower speeds to your needs so you can continue an enjoyable stay at home.

Read from these posts about Carrier furnaces:

Do Carrier Furnaces Have Humidifiers?

New Carrier Furnace Noisy – Why And What To Do?

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