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Heater Not Working? Troubleshooting Tips

InterCounty Supply • Feb 10, 2021

Heater Not Working?

Check Out These Troubleshooting Tips

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Whether you own a furnace, heat pump, boiler, or any other type of heating system, these machines are very important. Without this equipment working hard for your family every single day, it would be challenging to stay comfortable.


While these systems work tirelessly to keep our homes warm, they can run into problems at some point. Heater stopped working all of a sudden? If your heating system simply won’t power on, this is a common problem you’re experiencing. Luckily, there are some simple troubleshooting tips. Keep reading to learn more about how to fix this troubling system issue.

Examine The Heater Filter

On many occasions, heat not working is a result of a dirty filter. If these aren’t changed periodically, this could affect your home's air movement, not to mention your indoor air quality. Both of these factors can impact the health of your heater, causing it to not work properly.


As these factors can make your furnace or heat pump work harder than it should, this could drive up operating costs and decrease your system's longevity. If your heater isn’t working at all, change your filters. Look at your heater’s manual to find the exact location of your filter, including how to remove it.


Change your filter once a month if you use a flat option. If your system uses pleated filters, these should be inspected once a month. If you can’t see through your filter when you hold it up to a light, it needs to be changed. Pleated filters will typically last for three months; however, you may need to change them more often if you have kids or pets.

Check Your Thermostat Settings

It may sound surprising, but your thermostat settings may cause operational issues with your heating system. First, make sure your thermostat is set to “heat.” While this may sound obvious, incorrect thermostat settings are among the leading causes of a heater not working. This is especially true with programmable systems, which can be complicated to use. That said, it’s worth checking to see if your thermostat is set up correctly before assuming your furnace has another problem.



Your thermostat should read a temperature that will kick on your heating system. After setting this temp, wait a minute or two for the system to power up. If nothing happens, set your thermostat to 90 degrees so it won’t operate while you try to solve the problem.


If nothing seems to be working, follow the wires from your thermostat to your system and look for wire breaks. If you find one, splice it together and cover it with electrical tape. If this doesn’t solve your problem, try replacing the battery in your thermostat.


If you would rather not mess with any wires, call a professional HVAC technician. These experts can perform these tasks for you and get your heater back up and running right away.

Check The Fuse Box

Another troubleshooting tip is to examine the fuse box that powers your heating system. You’ll want to check and see if any electrical breakers have been tripped. Sometimes a simple reset of a tripped breaker can solve the problem.


If the power continues to trip off for your furnace, a safety feature could have been activated. If that’s the case, call an HVAC service provider for help. Since this may be an electrical issue, they can help diagnose the problem and find a solution.


Furnaces and heaters come built with several safety measures. These features will shut down your system if there’s a problem. Here is more information regarding the common safety measures in these units:

Furnace Safety Switch Or Upper Limit Switch

This feature looks for high temperatures and will turn off your furnace if things get too warm. This is done to prevent a fire. Many scenarios can cause this dangerous increase in temperature, and it typically happens when there isn’t adequate airflow. Common culprits to this issue include problems with your blower motor, capacitor, or control board. An HVAC professional can fix the issue and reset these features to get your system working correctly.

Vent Safety Switch

The typical home heating system produces flue gasses that are ventilated through the top of your roof. A vent safety switch monitors these gases as they cross the heat exchanger and pour out of your home. This switch is designed to confirm that these gasses can escape from your system safely. If this switch is enabled, your furnace will not power on.



There are a few common causes of this problem. For one, this vent could be blocked by a bird or wasp nest. Secondly, you could have a buildup of a chalky substance that comes from the gas odorant. When some gases burn, they produce this chalky substance that can build up over time. Luckily, an HVAC service professional can clean this up right away!

Thermocouple Or Flame Sensor

This safety feature looks for a pilot light that’s weak or one that doesn’t turn on at all. If that's the case, this safety measure will turn off your heater to prevent an explosion. A thermocouple sensor is found in older systems, while a flame sensor is used in modern units.

Check The Power Switch

While you may think it’s obvious, you never know if your furnace’s power switch was accidentally turned off. Unfortunately, many heating systems have an on-off switch that is far too easy to switch off by accident. If you find yourself walking past your furnace often, you could have hit the switch by mistake. Also, consider if you’ve had any service professionals around your home lately. It’s very possible they could’ve switched the power off by accident. If you have a heater not turning on, checking the power switch should be your first step.

Notice Any Odors?

If your heating system isn't working, you shouldn’t be able to smell anything in the air. If you do, this could be a sign of a gas leak, which could pose a life-threatening situation. If you notice a gas or smoky smell, call an HVAC professional immediately.


However, leaking gas isn’t always obvious. That said, be sure to install carbon monoxide detectors and smoke alarms. As this gas is odorless, detecting a leak isn't easy. If your carbon monoxide detector goes off, remove everyone from your home and contact your local fire department.

Flush Out Drain Lines

During the winter months, it’s common for a furnace to drain out gallons of water every single day. However, your system may not turn on if the drain line becomes clogged with mold or sediment. To troubleshoot this:


  1. Examine the drain hose to see if it’s dirty.
  2. If it is, remove the hose and fill it up with a mixture of bleach and water.
  3. Once it sits for a few hours, clean it out and return to its normal position.


Contact An HVAC Service Provider For Assistance

Knowing how to troubleshoot heating system issues can be complicated and confusing, especially if you don’t know much about these units. Luckily, an HVAC professional can offer fast and trusted repairs. If you’re experiencing a heater not working, try the troubleshooting tips above or call an HVAC expert for help!

Homeowner Looking For Reliable Heating, Cooling Or Plumbing Supplies?

Our dedicated specialists are standing by to help.

Most homeowners in need of new heating or cooling equipment will do an internet search to get information. Such a search will typically yield two results: what to buy or where to buy but not why to buy. At InterCounty Supply, as a wholesale supply house, we present all the options for what to buy and why it would be the best choice for YOUR situation. After all the options are presented a homeowner can decide for themselves what they need. ICS then has a licensed, factory trained contractor who SPECIALIZES in the equipment you need come to your home to provide the complete installation cost for the equipment you need. ICS will also handle all the paperwork for any rebates that are applicable.


Have questions, give us a call 914-939-4350 or fill out the form and one of our specialists will be in touch shortly.


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