When your home furnace isn't kicking-on on those cold winter days, it can quickly become more than an inconvenience. Many common furnace issues can explain why a furnace isn't working. Some fixes are as simple and easy as turning on a blown pilot light or too complicated that you must call an HVAC professional.
Thermostat Issues
Your thermostat is the command center for your heating system, and often, furnace problems start here. Before assuming the worst, check these thermostat-related issues:
- Your thermostat's power source might be compromised. If your home's thermostat is battery-operated, replacing the batteries is a good first step. For hardwired thermostats, check if the display is blank, which could indicate a tripped circuit breaker.
- Your thermostat settings might need correcting. Ensure it gets set to "heat" mode and the setting is slightly higher than the room temperature. Sometimes, accidental programming changes or power outages can reset your thermostat settings.
Power Supply Problems
Your furnace needs electricity to run, even if it's gas-powered. Several electrical issues could prevent your furnace from starting:
- Circuit Breaker Tripped: Locate the electrical panel and check that the furnace's circuit breaker tripped to the "off" position. If it has, flip it back on, but be aware that frequent tripping could indicate a more serious electrical problem.
- Power Switched Off: The furnace power switch often resembles a regular light switch mounted on or near your furnace. Sometimes, it gets accidentally turned off during cleaning or other household activities.
Dirty or Faulty Air Filters
Your furnace needs proper airflow to function safely and efficiently. When air filters become excessively dirty, they restrict this airflow and trigger your furnace's safety switch.
Check your air filter's condition. If you can't see light through it when holding it up to a light source, it's time for a replacement. Remember to change your filter every one to three months, depending on your home's conditions and filter type.
Gas Supply Issues
For gas furnaces, check if your gas valve is open. Sometimes, these valves get accidentally closed during maintenance or other work around the house. Ensure the valve handle is parallel with the gas line because this indicates that the gas line is open and flowing.
If other gas appliances need fixing, contact your gas company to verify service hasn't been interrupted.
Safety Switch Activation
Modern furnaces have multiple safety features that can prevent operation if they detect potential problems. These safety features are designed to keep you and your home safe, providing you with a sense of security and confidence in your furnace system.
The door switch ensures your furnace won't run while removing the access panel. Make sure all panels are properly secured.
If your furnace condensate pan is full, it will need draining. Many newer furnaces won't operate if the drain pan is full to prevent water damage.
Pilot Light or Ignition Problems
Due to drafts or dirty gas ports, older furnaces with standing pilot lights can go out. If you have this type of furnace, check if the pilot light is lit. If you smell gas, exit your home immediately and contact emergency services.
Newer furnaces use electronic ignition systems that can fail over time. If you hear clicking sounds when your furnace tries to start but it never ignites, this could indicate an ignition system problem.
Dirty Flame Sensor
A flame sensor verifies your furnace has adequately ignited. When this sensor becomes covered in carbon deposits, it may not detect the flame and shut off your furnace occasionally.
Cleaning a flame sensor is relatively simple but involves working with sensitive components. This job is best left to professionals.
When To Call a Professional
If you've checked the obvious problems and your furnace still won't start, it's time to call in experts. Contact Clements Plumbing Heating and Air today for furnace repair and maintenance.
