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Common Furnace Problems & Troubleshoots
Dec
As homeowners, we rely on our furnaces to keep our homes warm and comfortable during the cold winter months. However, like any system, furnaces can break down and experience issues that prevent them from working properly. That’s why we’ve put together this guide to address the most common furnace problems and provide troubleshooting tips to help you fix them.
From a furnace not heating or blowing cold air to a pilot light that goes out or a furnace that won’t turn on, we’ve got you covered. We’ll explore furnace combustion problems, thermostat issues, and ignition problems to help you resolve any furnace issues you may be facing. With our guide, you’ll be able to troubleshoot and fix most furnace problems on your own, saving you time and money.
If you are experiencing any of these issues, please don’t hesitate to contact One Stop HVAC for professional furnace repair.
Common Furnace Repairs & Troubleshoots:
1. Furnace Is Not Heating At All
It’s frustrating when your furnace isn’t heating your home properly, especially during the chilly winter months. Luckily, we’re here to help you troubleshoot and potentially fix the problem.
The first step is to check your furnace’s air filter. A dirty filter can obstruct airflow and cause your furnace to overheat, resulting in it shutting down.
If the air filter is clean, then the problem may be with the thermostat. Check to see if it’s set to “heat” mode and that the temperature is set high enough to trigger the furnace to turn on. If that’s all good, try removing the thermostat from the wall and checking the wiring behind it. Sometimes a loose wire can cause the furnace to malfunction.
If you’ve checked the filter and thermostat and the furnace is still not heating, the problem may be with the ignition system. Check to see if the pilot light is on, and if it’s not, try relighting it. If the pilot light won’t stay lit, it could be a sign of a bigger issue that requires a professional’s help.
Common Furnace Thermostat Issues
| Thermostat Issue | What to Check | How to Fix |
|---|---|---|
| Thermostat isn’t working at all | Check the wires behind the thermostat to ensure they are properly connected | If the wires are loose, tighten them. If this doesn’t work, it may be time to replace the thermostat |
| Thermostat is reading the wrong temperature | Try resetting your thermostat to its factory settings | If this doesn’t work, it may be time to replace the thermostat |
| Thermostat is set to heat but isn’t turning on the furnace | Check the wires behind the thermostat to ensure they are properly connected | If the wires are loose, tighten them. If this doesn’t work, it may be time to replace the thermostat |
Thermostat issues can also cause the furnace to not heat properly, so it’s important to address them when troubleshooting furnace problems.
2. Furnace Is Running But No Heat
If you’ve turned on your furnace and noticed that there’s no heat coming out, there could be a problem with the ignition system. This issue can be frustrating, but don’t worry, we’re here to help.
The first step in troubleshooting this issue is to check if the furnace is receiving power. A tripped circuit breaker or a blown fuse could be the culprit. Make sure to check the circuit box and replace any blown fuses.
If the furnace is receiving power, the next step is to check the pilot light. If the pilot light is out, you’ll need to relight it. Refer to our Table 1: Steps to Relight a Furnace Pilot Light for instructions on how to do this safely.
If the pilot light is on but the furnace still isn’t producing heat, there may be an issue with the ignition system. This could be caused by a faulty thermocouple or a damaged igniter. Refer to Table 2: Troubleshooting No Heat from Furnace for further guidance on how to resolve this issue.
Table 1: Steps to Relight a Furnace Pilot Light
| Step | Description |
|---|---|
| Step 1 | Turn off the furnace and wait for 10-15 minutes for any gas to dissipate. |
| Step 2 | Access the furnace’s pilot light assembly panel and remove it. |
| Step 3 | Find the pilot light and its control valve, located near the furnace burner. |
| Step 4 | Turn the control valve to “off”. Wait for a few seconds, then turn it to “pilot”. |
| Step 5 | Push and hold the control valve button down while lighting the pilot light with a long lighter or matchstick. |
| Step 6 | Keep holding the button down for a few seconds, then release it. |
| Step 7 | Turn the control valve to “on”. The furnace should start working again. |
Table 2: Troubleshooting No Heat from Furnace
| Issue | Solution |
|---|---|
| The thermocouple is faulty. | Replace the thermocouple. |
| The igniter is damaged. | Replace the igniter. |
| The gas valve is faulty. | Replace the gas valve. |
| The furnace filter is dirty. | Replace the furnace filter. |
3. Furnace Pilot Has Light Gone Out
One of the most common issues that homeowners face with their furnace is a pilot light that goes out, causing the furnace to stop working properly leaving you without heat.
There are several reasons why the pilot light on your furnace may go out, including a faulty thermocouple, a clogged pilot orifice, or a dirty pilot tube.
To troubleshoot this issue, start by turning off the furnace and waiting for it to cool down completely. Check the pilot light for any visible damage or debris. If you notice any, carefully clean the area around the pilot. You can use a small brush or compressed air to remove any dirt or debris.
If the pilot seems intact, attempt to relight it following the manufacturer’s instructions. You may need to hold down the light button for several seconds to reignite the pilot.
Remember, if you smell gas or suspect a gas leak, turn off the furnace immediately and contact One Stop HVAC for assistance.
Furnace Pilot Light Troubleshooting Table
| Possible Cause | Troubleshooting Steps |
|---|---|
| Dirty pilot tube | Use a small brush or compressed air to clean the pilot tube and surrounding area. Attempt to relight the pilot. |
| Faulty thermocouple | Replace the thermocouple or contact a qualified HVAC technician for assistance. |
| Clogged pilot orifice | Carefully clean the pilot orifice with a small brush or compressed air. Attempt to relight the pilot. |
With these troubleshooting steps, you can address furnace ignition problems like a pilot light that goes out and relight it safely. If you still experience issues with your furnace, consider contacting a qualified HVAC technician for assistance.
4. Furnace Is Blowing Cold Air
When your furnace is blowing cold air instead of warm air, it can be frustrating and uncomfortable. This is a common problem that can be caused by a range of issues related to the furnace’s combustion system.
The first step to resolving this issue is to identify the potential problems. Some of the most common causes of a furnace blowing cold air include:
- Dirty or clogged air filters
- Malfunctioning thermostat
- Furnace combustion problems
- Blocked air ducts
If you have ruled out simple issues like dirty filters and blocked air ducts, you may need to investigate the combustion system of your furnace. This system consists of several components, including the pilot light, gas valve, and ignitor. If any of these components are malfunctioning, it can result in your furnace blowing cold air.
One of the best ways to troubleshoot a furnace combustion problem is to check the furnace’s pilot light. If the pilot light is out, you may need to relight it. However, if the pilot light keeps going out, it could be a sign of a more serious issue that requires professional attention.
If you are experiencing issues with your furnace blowing cold air, our team at One Stop HVAC can help. Our experienced technicians will diagnose and resolve any furnace combustion problems to ensure your home stays warm and comfortable through the winter.
5. Furnace Is Not Turning On
Is your furnace refusing to turn on, and you’re not sure what to do? There could be several reasons why your furnace is not turning on, including problems with the furnace’s combustion system. But don’t worry, we’ve got you covered. Follow these troubleshooting steps to help get your furnace up and running again:
- Check the thermostat: Ensure that the thermostat is on and set to the desired temperature. If the thermostat’s batteries are dead, replace them and try again.
- Inspect the filter: A dirty air filter can obstruct airflow and cause problems with your furnace’s operation. Check the filter, and if it’s dirty, replace it with a new one.
- Check the power source: Make sure that your furnace is properly connected to the power source and that the circuit breaker is on. If the breaker has tripped, reset it and see if that helps.
- Inspect the flame sensor: A dirty flame sensor can prevent your furnace from turning on. Inspect the sensor and clean it if necessary.
- Check the gas supply: If your furnace runs on gas, make sure that your gas supply is on and that the fuel valve is open. If you suspect that there’s a problem with the gas line, contact a professional.
If you’ve tried these troubleshooting steps and your furnace still won’t turn on, it’s time to call in a professional. Ignoring furnace combustion problems can be dangerous and may cause further damage to your furnace.
If you are experiencing frequent furnace problems, it might be time for a furnace upgrade. One Stop HVAC offers professional furnace installation services for all major makes and models, including Lennox, Goodman, KeepRite and more!
Common Furnace Thermostat Issues
If your furnace is experiencing issues with its performance, it may be the thermostat causing the problem. Common thermostat issues include incorrect temperature readings, a malfunctioning display, or a thermostat that won’t turn on. Fortunately, many of these issues can be easily resolved with some troubleshooting.
Before performing any troubleshooting steps, make sure your thermostat is set to “heat” and is set to your desired temperature. If the thermostat is set correctly and you are still experiencing issues, try the following:
- Check the batteries: If your thermostat uses batteries, ensure they are fresh and installed correctly. Low battery life can cause your thermostat to malfunction and impact your furnace’s operation.
- Clean your thermostat: Dirt and debris can accumulate on the thermostat’s sensors, affecting its performance. Use a soft cloth to gently clean your thermostat and remove any buildup.
- Check the wiring: If your thermostat is wired incorrectly, it can lead to performance issues. Turn off power to your furnace and remove the front panel of your thermostat to check for any loose or disconnected wires.
If these steps do not resolve your thermostat issues, it may be time to call a One Stop HVAC. We will be able to diagnose and resolve any more complex issues that may be impacting your furnace’s performance.
Remember, a properly functioning thermostat is essential for maintaining optimal heating in your home. If you are experiencing furnace thermostat issues or any other problems with your furnace’s performance, don’t hesitate to contact us for assistance. We are always here to help!
FAQ
What are some common furnace problems?
Common furnace problems include the furnace not heating properly, blowing cold air, not turning on, or having issues with the pilot light, ignition, or thermostat.
How can I troubleshoot a furnace that is not heating?
If your furnace is not heating, check if the thermostat is set to a higher temperature, ensure the furnace filter is clean, and confirm that the gas supply is on. If these steps don’t work, it’s recommended to call a professional technician.
What should I do if there is no heat from my furnace?
If there is no heat from your furnace, check if the pilot light is lit. If it’s not, follow the manufacturer’s instructions to relight it. If the pilot light is already lit, check for other potential issues such as a faulty igniter or gas valve, and consider calling a professional for further assistance.
How do I relight the pilot light on my furnace?
To relight the pilot light, turn off the gas supply, wait for a few minutes, locate the pilot light assembly, and follow the manufacturer’s instructions to relight it safely. If you’re unsure or uncomfortable performing this task, contact a professional.
What can cause a furnace to blow cold air?
A furnace blowing cold air may indicate problems with the combustion system, such as a clogged burner or a faulty limit switch. Check for these issues, clean or replace components if necessary, and ensure proper airflow in the system. If the problem persists, consult a professional technician.
How can I troubleshoot a furnace that is not turning on?
If your furnace is not turning on, check if the circuit breaker or fuse for the furnace is tripped or blown. Also, ensure the thermostat is set to the appropriate temperature and functioning correctly. If these steps don’t resolve the issue, it’s advisable to contact a professional technician.
What should I do if I suspect thermostat issues with my furnace?
If you suspect thermostat issues with your furnace, start by checking the thermostat settings and battery level, if applicable. Ensure the thermostat is properly calibrated and located away from heat sources or drafts. If the issue persists, consider replacing the thermostat or consulting a professional for further assistance.
