Furnace troubles are the last thing you need once the weather turns cold. Furnace not kicking on when the temperature drops? It may be there’s a simple issue that can be easily fixed. But sometimes it’s a more serious problem that needs expert attention.
6 Reasons Your Heater Isn’t Turning On
1. Check That the Furnace Is Switched On
The first rule of troubleshooting is to always check for the easy fix first. If you think you’d feel silly checking if the furnace is switched on now, imagine how you’d feel if you discovered that the furnace was switched off after five fruitless hours of investigating other solutions!
The power switch for the furnace should be located on a nearby wall or might be on a nearby joist. Furnace switches most often look like light switches, and they’re not always labeled or labeled correctly. The ON position for a furnace switch is usually UP. If the switch isn’t on, turn it on and give the system a few minutes to start up.
Another good thing to do at this point is to check your circuit breakers. Make sure everything’s in the right position and that your furnace is actually getting the power it should have.
2. Check Thermostat Settings
One common issue that might prevent your furnace kicking on is simply that the thermostat isn’t set correctly. In winter, the thermostat should be on the “heat” setting and should be set higher than the ambient temperature. It may seem obvious, but these kinds of errors are easier to overlook than you think!
If you have a digital thermostat, check the display panel to see if there’s an error code showing. If there is, that might give you some clues as to what the problem is.
3. Check for Dirty Filters
If your furnace’s filter hasn’t been changed recently, it could have become dirty enough that airflow has been reduced or even stopped altogether. If so, that could be a reason your furnace isn’t kicking on.
Standard filters should be replaced at least every 90 days. You may need to change the filter as often as every 30 days if:
- You have pets
- You use the furnace frequently
- You have poor indoor air quality for any reason
4. Check for Blocked Vent Registers
Is warm air flowing in some parts of the house but not in others? Check the vent registers in the rooms that aren’t getting warm air. They could be blocked and restricting airflow in those areas. Make sure there’s no debris in the vents themselves and that there’s no furniture, carpets, rugs, or anything else covering up the vents.
5. Make Sure the Gas Is On
If your furnace is gas-powered, then a disruption to the gas supply might prevent the furnace kicking on when the temperature drops. It’s possible that the gas line to the furnace might have been turned off inadvertently over the summer, without anyone noticing.
Here’s what to check to verify that your gas is working:
- Check that the gas valve at the furnace is turned on.
- Verify that any other gas-powered appliances in the home are working. For instance, if your gas oven is fine, but the furnace isn’t, then there’s most likely an issue with the furnace, rather than that gas supply.
- Check that your home’s external and internal gas valves are turned on. If they are, but no gas-powered appliances are working, call your gas company and ask about service interruptions.
Beyond this point, it’s best to call in a professional furnace technician. It’s generally unsafe for homeowners to take on home gas line repairs.
In addition, if at any time you smell gas in your home or have any reason to suspect a gas leak, you and anyone else at home should evacuate immediately. Head outside right away, and then call emergency services or your gas company for further help.
6. Find Out If the Furnace Is Igniting
If the furnace itself isn’t igniting, the problem may be the pilot light or ignition sensor. If you can hear the heat click on but nothing happens, either of these could be the culprit.
Pilot light: Older gas furnaces have a pilot light, a small flame that burns gas as it comes through the gas line into the main burner. If the pilot light stops burning, so does the furnace. The pilot light might malfunction if:
- Gusts of air blow the pilot light out
- The gas is turned off
- The pilot light orifice is dirty – This can prevent the pilot light from burning properly and may cause it to keep going out. If the pilot flame looks yellow or red, that’s a sign it’s not getting a steady supply of fuel.
- The thermocouple is faulty – This small electrical device provides the pilot light with the power it needs to be self-sustaining. A dirty thermocouple can prevent the pilot light working properly.
Ignition sensor: This is a safety feature for gas furnaces. If the sensor is unable to detect a burning flame, it shuts the furnace down to prevent unburned gas from leaking. The ignition sensor can stop functioning correctly if it becomes very dirty because it makes the sensor unreliable.
To troubleshoot, turn off the furnace, including the gas. Next, remove the front furnace panel. The ignition sensor, pilot light, and thermocouple can typically be located by removing the front furnace panel. They’re usually near the burners.
All three can malfunction if they’re dirty. If you feel confident in your DIY abilities, cleaning them can potentially resolve a problem where your furnace isn’t kicking on. But these are delicate pieces of machinery and must be handled very carefully.
Also make sure that you follow appropriate gas safety precautions. Turn off the gas first, before doing anything else, and don’t hesitate to evacuate if you suspect a gas leak.
When to Call a Professional Furnace Technician
Simple issues such as blocked vent registers and dirty filters are things most homeowners can take on themselves with some furnace troubleshooting tips. But there are situations where it’s better to get professional help.
For instance, if you go through some simple troubleshooting steps and your heater still doesn’t turn on, then it’s time to bring in an expert who can look for less obvious problems.
If you suspect an issue with a gas line and have already checked that it’s unobstructed, your next step should be to call a professional. It’s not safe to take on gas repairs yourself unless you have the required training and certification.
In general, if there are any repairs or maintenance tasks you just don’t feel confident with, it’s a good idea to call a professional. For instance, it’s possible to clean a dirty ignition sensor or thermocouple yourself, if you have some experience and feel confident in your abilities. But if you’re not sure what you’re doing, it’s easy to accidentally break these delicate items.
If you’re not completely sure about DIY furnace repair, call a professional, like those at CW Service Pros. You’ll have the peace of mind that comes with knowing the job’s been done correctly and that you can rely on your furnace all winter long.
Need Help with Your Furnace? Call the North Texas Experts, CW Service Pros!
The last thing you want on a cold winter night is to find that your heater isn’t kicking on! Now’s the time to have your furnace checked over and make sure it’s ready for the cold weather. Whether there’s a problem with your furnace or it’s time for routine furnace maintenance, CW Service Pros have you covered!