What to do when furnace wont shut off?

Frustrated by a furnace that won’t turn off?

We understand your frustration—and we’ll do our best to explain what causes this annoying problem and how you can fix it.

If your furnace won’t shut off, you likely have one of the following issues:

• Thermostat issue
• Dirty air filter
• Faulty blower
• Leaky air ducts

We’ll go into more detail about each of these issues below...

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Two thermostat problems could be causing your furnace to run continuously:

1. Your thermostat is set incorrectly
2. Your thermostat has a wiring issue

Incorrect thermostat setting

Your thermostat controls your furnace fan. Sometimes the fan setting accidentally gets changed to the wrong position.

The correct setting is AUTO. Make sure your thermostat is set to AUTO instead of ON.

Set your thermostat to AUTO instead of ON

Here’s the difference between the two fan settings:

• When your thermostat is set to ON, your furnace fan will run non-stop, which could be what is causing your furnace to sound like it’s not turning off
• When your thermostat is set to AUTO, your furnace fan will run only while your furnace is heating your home’s air

Wiring issue

If your thermostat is set to AUTO and everything else seems to be working, the issue could be with the thermostat itself.

Over time, the wiring that connects the thermostat to your furnace can start to wear out. This could prevent your furnace from turning off.

Instead of attempting to fix the wiring issue yourself, we recommend contacting a professional to inspect your thermostat. Electrical issues are often complex and potentially dangerous to fix, which is why it’s best to let a pro handle this job.

A dirty air filter blocks air from entering your furnace, which could be causing your furnace to run non-stop.

Here’s why: When you set your thermostat to HEAT, your furnace starts pulling in cold air from inside your home to be heated. This air passes through the air filter where any large particles are removed from the air before it reaches your furnace.

However, if your filter accumulates too much dirt and debris, air will have a difficult time passing through the filter, which means little or no air will reach your furnace. The less air your furnace pulls in, the less hot air it can breathe out. This means your furnace will have to run longer to get your home to your desired temperature, which may be the reason your furnace is running continuously.

Do this: Check your air filter. If it is dirty, replace it with a new one. Then, run your furnace as normal and wait a couple of hours. If you still hear your furnace running non-stop during that time, contact a professional for help.

If your filter looks like the one on the right, it’s dirty and needs to be replaced

Like we mentioned above, your furnace has a blower that pulls in cold air to be heated and pushes out warm air into your home.

This blower is powered by a motor, which can start to malfunction over time. The most common blower problem that makes your furnace run non-stop is a faulty limit switch. A limit switch is the part of your furnace that tells your system when to turn on and off. If it’s broken, your furnace won’t know when to shut off and will continue to run.

If this is your issue, you’ll need to hire an HVAC professional to fix it. Fixing a broken fan limit switch requires electrical skills and know-how, which is why we recommend letting a professional handle this job.

If you have leaky air ducts (specifically on the supply side, seen in the image below), then heated air might be leaking into the attic instead of going into your home.

A leak on the supply side of your ductwork means warm air is escaping into your attic

If you’re losing heated air, your furnace will have to produce more heated air to warm your home, which means longer run times.

You might have leaky ducts if you notice the following signs:

• Uneven heating throughout the house
• Lots of dust in your home
• Higher-than-normal utility bills

If you notice these signs, have a duct specialist inspect your ductwork for leaks. If they find that your ducts have leaks, you’ll need them to be repaired (sealed).

Schedule appointment today

We offer same-day service! Our technicians are standing by to help.

For more information about what to expect when you hire us, visit our furnace repair page.

Normally, when we think of a heating problem, we immediately think about the furnace not turning on. However, a furnace that won’t shut off can be equally frustrating. If your heating system is playing on repeat, it is probably getting pretty-toasty and uncomfortable inside. Here are a few steps you can take to turn off the heat before giving Robert B. Payne Inc. a call:

• Check the thermostat: If your thermostat takes batteries first check to make sure they do not need to be replaced. If you are sure that the batteries are working, or if your thermostat has a direct connection to your home’s electric, then turn the thermostat’s setting to off. Give your system a bit and see if it shuts down. If after 3 or so minutes your system is still running then you may need to cut the power to the whole heating system.

• What if my thermostat doesn’t have an off switch?: The easiest solution is to turn the temperature of the thermostat below the current room temperature by at least a several degrees. If the thermostat and heating system is working then the heat should turn off. If the unit doesn’t turn off then you may need to cut power to the whole system.

• Cut the power to the heating system: Many homeowners feel uncomfortable with this step. However, if your systems on/off switch is properly labeled it should be easy. Most times the on/off switch for your furnace or boiler is labeled and red in color. Just turn the switch to off and give us a call.

Why Won’t the Heat Turn Off?

There are a couple potential reasons why your heating system won’t turn off:

• Bad thermostat: A faulty thermostat can normally be repaired. Faulty wiring, a broken switch, or broken heating sensor can be fixed depending on how severe the issue is. If the thermostat can’t be repaired it can certainly be replaced, and with today’s advanced thermostat technology there are many exciting new options available.

• Damaged primary controller: If the problem isn’t with the thermostat the next place we look is the heating unit itself. Normally, when we have a heating system that won’t turn off, the problem lies with the primary controller. If it isn’t the primary controller, we will find the mechanical problem with the system and repair it.

• Defective Water checking system: If your home uses radiators or hot water to heat the home the issue may lie with your water checking system. Normally the problem specifically lies with the water check valve. If the check valve is defective, then water will keep circulating through the system and the heat will not turn off. One of our expert technicians can fix this valve or any other problem that may be affecting the water checking system.

If you feel like you’re in an oven because the heat keeps running the first step to this problem is to turn the heat off using the steps above. Next give Robert B. Payne Inc. a call and one of our expert technicians will diagnose the problem and give you the best options for repair or replacement based on your budget and needs.

Whether it’s a mild winter in Phoenix or you’re experiencing arctic temperatures, a working furnace can be a lifesaver. However, a furnace that won’t turn off can be a major issue in the most inconvenient times. Your Phoenix furnace should have natural cycles where it turns on and off. A furnace that won’t shut off can be costly and damaging. Learn some common issues that you can fix, as well as other issues that require professional help with this comprehensive guide.

Identify the Issue

There are many signs that indicate your furnace isn’t working properly, but a common problem is a furnace that continues to run. Take a look at these five common problems, and learn what you can do to fix them:

1. Wrong thermostat setting
2. Old air filter
3. Damaged thermostat
4. Damaged blower motor
5. Ductwork that leaks

We’ll take you step-by-step through each issue to find the right solution for your home. If the solution is manageable on your own, your furnace will be working properly again in no time. Otherwise, our professional team at Day & Night Air can fix your furnace with friendly and prompt service.

Proper Furnace Maintenance

Before any of these issues arise, or after they’ve been successfully fixed, proper Phoenix furnace maintenance can help you avoid costly repairs in the future. Some furnace maintenance can be complicated, but there are some basic tips you can do on your own.

Keep your thermostat adjusted correctly. During summer, you may want to keep your home slightly warmer in order to save on energy costs. However, during the winter, you may want to adjust the temperature lower. This allows you to not only save money on your heating bill, but also helps keep your furnace running longer. An overworked furnace won’t last as long as a furnace set at an efficient temperature. Here is a list of things to check to try to uncover the issue you are facing with your furnace:

Step 1: Check the Thermostat

If your furnace won’t turn off, the easiest issue to fix is your thermostat. There are two basic ways you can adjust your thermostat to ensure it isn’t what’s keeping your blower running. First, your temperature may be set too high. A furnace that is working hard to keep a high temperature, especially when it’s extra cold outside, can seem to run continuously.

The second common thermostat problem is the fan switch. Your fan can be adjusted manually from your thermostat. Many thermostats have two settings: AUTO and ON. Other thermostats also have an OFF selection. Make sure your fan switch isn’t turned to the ON setting. This keeps your fan running constantly, even if the furnace isn’t producing hot air. If your blower is still running even after the temperature and fan switch have been adjusted, it’s time to go to your furnace and check out the air filter.

Step 2: Check the Air Filter

When was the last time you changed your air filter? A clogged air filter can dramatically decrease the air flow of your entire system. This can cause your furnace to run far longer, even continuously.

There are many factors that can determine when to change an air filter. Here are just a few things to consider that may require you to change your filter more frequently than typical:

• Pets
• An unusually dusty home
• Smoking
• Keeping doors and windows open often
• Filter size
• The length of time the blower is on

Filters are generally changed every three months, but these factors can increase or decrease that time. Some filters can last up to 12 months, while others should be replaced monthly. Ask a professional about your particular furnace and home situation to determine the ideal frequency for you.

To replace a furnace filter, simply locate the filter, remove the old filter, and replace with a new one. Be sure to choose the exact size of your old filter, which should have the measurements printed clearly on the side. If your filter has a plastic frame, it may be a reusable model that simply needs to be rinsed and air-dried. Homes that require frequent filter replacements should consider investing in a reusable filter. You’ll still need to clean the filter frequently, but this can be a great investment if you need to replace your filter often.

After replacing your filter, you should notice a significant difference in the sound and volume of airflow. If not, consider contacting a professional to determine the next step.

Issues That Require Professional Help

Professional heating and air service companies, such as Day & Night Air in Phoenix can promptly diagnose and fix any furnace issue. If your furnace won’t shut off after adjusting the thermostat and replacing the air filter, it’s time to call a heating repair service. At Day & Night Air, our dedicated service team works around the clock. Any time of day, any day of the year you can set an appointment for service with a trained Phoenix technician who can help you fix your furnace and get warm air quickly.

Based in Phoenix, Arizona, our technicians are able to deal with local problems and find effective solutions. Here are just a few common issues that require professional services.

Issue 1: Thermostat Malfunction

A thermostat is a complicated system that sends signals to your furnace and blower depending on the temperature it detects in the room. Some thermostat malfunctions are caused by faulty wiring. Wiring issues require experience with electricity, so it’s not a good idea to attempt to repair a thermostat on your own.

Whether you need a new thermostat, new part, or just wires that need to be reconnected, a professional HVAC technician can quickly solve this issue. Even if your furnace begins turning on and off correctly, you may want to consider replacing your thermostat if you feel the temperature isn’t accurate or consistent.

Issue 2: Damaged Blower Motor

The blower is the part of your HVAC system that forces both hot and cold air throughout your home. If you have a central air conditioner, this system will also use your blower. An air blower has many complicated parts that can need to be repaired or replaced.

A blower that won’t turn on is more frequently associated with a damaged blower motor, but some issues can cause the motor to stay running. Either way, this system requires extensive knowledge of the electrical and mechanical components of an HVAC system. DIY repairs can cause more damage to your system and working with electricity around natural gas or propane can be dangerous. Contact an expert at Day & Night Air to easily repair or replace your blower motor. We can discuss the problem in depth, and help you identify the most cost-effective solution for your home.

Issue 3: Ductwork Leaks

Ductwork is the metal system that is used to force air throughout your home. Whether you’re circulating cool air in the summer or warm air in the winter, ductwork is an essential part of your HVAC system that allows for even distribution of air.

Leaky ductwork is inefficient. With too many leaks in your ductwork, your home may not be circulating air effectively. If you notice uneven temperatures in your home, particularly if the room with your thermostat is cooler than other areas of your home, then the thermostat may not be reaching adequate temperatures to turn your furnace off.

Sealing ductwork can be time-consuming, particularly if you’re unsure of the exact location of the leak. You’ll also want to seal any leaks in your crawl space or attic, which can be a difficult job for many homeowners. Our expert HVAC technicians can diagnose any issues with your ductwork and quickly seal your ductwork.

Leaky, uninsulated ductwork can not only keep your furnace running, but it’s also inefficient. Even if your furnace shuts off, consider calling our team to keep your furnace running efficiently.

Replacing Your Furnace

If your heating won’t turn off, your furnace probably doesn’t need to be replaced. As long as the blower is still forcing warm air, your issue should be handled easily with a replacement part. However, some issues can be more serious, particularly if your furnace won’t turn on.

Discuss the health of your furnace with our Phoenix HVAC specialists. Replacing a furnace can be a costly decision, so you want to know as early as possible when your furnace may need to be replaced.

One particular issue that may require your furnace to be replaced is the size of your unit. If a furnace is too small, it may be overworked trying to heat your entire home. This is particularly common in a home that has recently been renovated or had an addition. If you’re attempting to heat a significantly larger space, you may need to consider a furnace upgrade.

A furnace is sized based on the BTUs it produces, so it can be difficult to find the exact model you need. An HVAC technician can perform accurate estimates to discover the ideal size furnace for your home and climate.

Contact Day & Night Air Today

If your furnace won’t shut off, don’t wait and suffer in a cold home. Contact us today to schedule a service appointment in Phoenix. Whether it’s the middle of the night, weekend, or a holiday, you’ll always enjoy prompt service from our team. Choose the best service in your area that offers comprehensive diagnostics, convenient scheduling, and local HVAC experts. We serve areas all across the state, including

• Phoenix
• Apache Junction
• Fountain Hills
• Arcadia
• Cave Creek
• Mesa
• Tempe
• And more

Whether you’re able to fix your furnace issue or not, our friendly technicians would be happy to assist you in learning more about your furnace. Discover how to properly maintain your furnace, and receive fast repairs and replacement parts with Day & Night Air. Running a furnace in Arizona in the winter can be expensive enough; don’t let a furnace that won’t shut off cost you even more on your next energy bill.