Common Furnace & Heating Issues
Our NATE Certified technicians are experienced with common furnace issues that stop your home heating systems from functioning in its tracks! Solve your home heating problems with our handy DIY guide on the most typical issues plaguing your HVAC equipment written by our experts!
-Notice your furnace igniting then immediately shutting off or failing to ignite and not heating your home?
Typically coupled with cool or room temperature air blowing from the vents after 3-5 attempts at lighting the burners, this issue can be a sign of Loss of Flame Signal, and is one of the most common issues we see. Flame Signal is provided to the furnace via a component called the Flame Sensor (a single metal rod encased with ceramic at the base which extends into the flames near the burner.) This flame sensor component is in flame any time your furnace is running, and as a result can build up a layer of carbon or ash on the exterior surface. This carbon can interrupt the flame signal from reaching the furnace control board, and stop your system from wasting gas erroneously.
Carbon Build Up on the Flame Sensor is an easy repair and well within the capabilities of most homeowners. Our technicians will generally remove the top cover panel of the furnace to access the burner compartment (a row of holes/burners attached to the gas valve via a black distribution tube) and clean the flame sensor rod with a rough surface like scotch-brite or very fine sandpaper. This will clean the oxidation layer away and allow for flame signal to enable your furnace to function correctly.
Other flame or ignition issues such as ignitor failure, gas valve failure, and electronic control issues can cause issues that may be difficult to diagnose without professional tools and assistance. Contact AtoZ Services for help at (657)777-2869.
-Notice your furnace intermittently blowing cold air while your thermostat says your heat system is running?
This can be a sign of overheating, or more technically, High Limit Temperature Protection. In many Gas and Electric Furnaces, there is a sensor (called a High Limit) that monitors your HVAC system temperatures and automatically stops additional heating and runs your blower fan to cool down your furnace before reaching dangerous temperatures outside of manufacturer recommendations. When our technicians see this in the field, our first two considerations are Airflow and Heat Input. If Airflow is too low, or Heat Input too high, you can run into this issue, and you may not even notice it until the coldest days of winter!
Recommended steps for homeowners are to check your HVAC system air filter(s). Dirty air filters can cause impedance or blockage to heating system airflow that reduces the heating capacity to your furnace and can stop it from functioning entirely! Reduce issues in your furnace by replacing or cleaning your air filter regularly. Most experts recommend replacing your disposable filter or cleaning your reusable filter every 3 months or less, but it will vary depending on filter type, size, and HVAC usage. Keeping this filter clean not only provides easy access to return air for your HVAC system to run efficiently, but also collects dust and contaminates from your home’s air to keep allergies at bay. For more information on HVAC air filters, we recommend our guide “Replacing your HVAC Air Filter.”
Heat Input is another variable to overheating or over-temperature issues with your furnace. This is typically set by the manufacturer but can be adjusted at the gas valve. A monometer is required to correctly set pressures according to manufacturer guidelines, but generally lays around 3.5 inWC at the output of the gas valve. For additional help making sure your furnace gas pressure is set correctly, contact our expert HVAC technicians at (657)777-2869.
