Heat Pump Blower Runs Continuously? (Possible Causes & Fixes)

Ryan Womeldorf
by Ryan Womeldorf

Our furnaces are quite the piece of equipment. There are a number of components within that allow it to deliver heat into our homes, keeping us warm even when the temperatures are subzero. And just like any other type of equipment, things can go wrong.

From time to time, you may notice that the heat pump blower continues to run. The reason that it keeps running is that the relay switch is bad, the thermostat is incorrectly programmed, or it could simply be due to freezing temperatures. Whatever the case, it is imperative to find a fix to ensure that your furnace or heat pump runs correctly during the winter.

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What is the Blower?

Though it is known by different names depending on where it is used, the blower has one job. That job is to distribute the air that has already been heated into your home. The blower does just that: blows the air through the vents and out into your home.

When the system works to heat the air, the blower works to force it through the duct system, out of the vents, and throughout the home. When the blower isn’t working correctly, you could be left without heat. That is a major concern during the coldest months of the year.

Different Types of Blowers

There are generally two types of blower motor that you need to know about: single and variable speed. It all depends on the type of system that you have installed.

  • Single-speed. A single-speed motor starts up when the thermostat relays the information that cooling and heating is required in the home. Whenever the requisite temperature is hit, it is supposed to turn off.
  • Variable-speed. With a variable speed HVAC blower, the motor operates at, you guessed it, variable speeds. The variable speeds are meant to deliver more precise temperature control through improved airflow. The electronically commutated motor (ECM) runs at a lower speed to provide superior air circulation for a higher level of air quality and comfort. Despite this, it still uses less energy than most single-speed motors.

How Do You Troubleshoot a Heat Pump Blower?

It should be noted that regular maintenance will help extend the life of the blower and the other components in your HVAC system. Moreover, proper maintenance will allow you to nip any potential issues in the bud before they become larger issues.

From time to time, there will be problems. Understanding how to troubleshoot the issues at hand is important. There are a few troubleshooting steps that you can take to try to alleviate the issue before calling in an HVAC technician.

Troubleshooting the Heat Pump Blower

  • System not turning on? Start by simply turning the system on. If it doesn’t turn on at all, the problem could be electrical. Check the main electrical panel in your home and make sure that none of the breakers have flipped. Make sure the on/off switch hasn’t been flipped, verifying it is on.
  • The system turns on. Should the system startup as it normally would but the blower doesn’t follow suit, try turning everything off. Cut the power to that outlet, too, by flipping the breaker. With the power off, take off the access panel so that you can have access to the component. Make sure to clear any debris or dirt that is built up near or on the motor.
  • Call in the tech. After you clean out the debris, the system should work fine. But if it doesn’t, you may need to place a call to your local HVAC technician. By calling them in, they can find the issue at hand and implement the proper repairs.

Heat Pump Condenser

Sometimes, when the fan runs continuously, it could be an issue with another part of the heat pump. When the portion of the heat pump that deals with refrigeration has a problem, auxiliary heating will kick on to offset that temperature.

Should there be something wrong with the condenser as it provides heat, then the auxiliary heating becomes the primary point of heating in the system. Start by checking out a few things:

  • Pump condenser. Start first by making sure that the heat pump condenser (which is outside) is running. If it isn’t working properly, check your breakers and fuses. More often than not, a breaker gets tripped and cuts the power to the unit as a whole.
  • Check the refrigeration lines. Should the heat pump condenser run, you can try touching the refrigeration lines that run into the condenser. Just be careful, the lines can be very hot if they are indeed working properly. When the lines are cold, then there may be a problem with the refrigeration part of the heat pump.
  • Control problem. When you get through the previous steps, it could be that there is a control problem. If that is the case, an HVAC technician is needed to check out the issue.

Maintenance is Key

While there is nothing that can be done to fully prevent breakdowns from occurring, regular maintenance is your furnace’s best friend. Regular cleaning and maintenance is meant to keep all of the components within your system working properly and free of debris.

Depending on your comfort level, you can perform the maintenance yourself. If you don’t feel great about it, an HVAC service can perform regular maintenance for you. Doing so will extend the life of your HVAC system and its various components, so don’t ignore it.

Should I Set my HVAC System’s Fan to Auto or On?

The fan setting on a thermostat controls the blower within your HVAC system. That blower will distribute hot air through your home, keeping it warm in the process. There are a pair of settings on your thermostat to be aware of: ON and AUTO.

The ON setting means the fan will be on constantly and will blow air even when the HVAC system is not actively cooling or heating.

AUTO. The AUTO function will kick on whenever the system is cooling or heating. When the temperature indicated on the thermostat is reached, then the system shuts off until it needs to cycle back on.

This is a personal preference, but there are definitely pros and cons to running the thermostat on AUTO or ON.

Pros and Cons of Setting the Thermostat to AUTO

The Pros:

  • Energy-efficient. When the fan only runs when necessary and not constantly, it is more energy-efficient. That can mean savings on your energy bill in the long-term.
  • Better dehumidification. Depending on where you live, things can get quite humid during the summer. When you set the thermostat to AUTO, then the moisture that accumulates on the cold cooling coils is able to drain outside. Letting the fan run constantly means the moisture can’t drip outside, instead blowing into your home.
  • Replacing the filter more often. Letting your thermostat run on auto means that you will need to replace the filter more often. While that seems like a negative, it means that you ensure that the filter is in good condition. That means less clogging, which results in other issues.

The Cons:

  • Inconsistent airflow. When the fan is on AUTO, there is less even distribution of cool or hot air. Moreover, the fan will turn off when it reaches the temperature designated on the thermostat.
  • Blower motor fan wear. The more starting and stopping that the fan does, the quicker it wears down. That could mean needing to replace it sooner rather than later.

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Pros and Cons of Setting the Thermostat to ON

The Pros:

  • Better air distribution. When the fan runs consistently, there is better air distribution in your home. Whereas the air will have cold or warm pockets with AUTO, those pockets should disappear with the fan constantly blowing.
  • Less stress on the fan. With fewer starts and stops, the fan could last much longer. Those starts and stops put stress on the fan, wearing it down faster should you leave the setting on AUTO.
  • Cleaner air. If you use a UV light or filtration system, constant airflow can create a better, cleaner air quality.

The Cons:

  • Costly. Keeping the fan running at all times can mean higher energy bills in the long run. There are even some systems that aren’t rated to run constantly, raising the costs even further.
  • Cool air in the winter. With the fan constantly running, you may notice cool air coming out of your vents in the winter. When you are trying to keep your home warm, it can be frustrating to feel cold air coming out.
  • Replacing the filter more often. While it is good to have a clean air filter, replacing it more often means having to pay for new filters. That can be costly over longer periods of time.
  • Hot air in the summer. Much the same as cool air blows in during the winter, you could experience warmer air blowing into your home in the summer. That can be frustrating to deal with when trying to stay cool.
Ryan Womeldorf
Ryan Womeldorf

Ryan Womeldorf has more than a decade of experience writing. He loves to blog about construction, plumbing, and other home topics. Ryan also loves hockey and a lifelong Buffalo sports fan.

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