There is nothing worse than flipping on your thermostat on a chilly morning only to discover your furnace won’t start. While this can feel like a major emergency, there are several common reasons your heating system might refuse to kick on. Some issues are simple enough to fix yourself, while others require a professional technician. Monterey Peninsula Sheet Metal & Heating would like to share why your furnace may fail to start up and what you can do about it.
Power Supply Problems
Your furnace will not start if it’s not getting power. First check the circuit breakers or fuses in the electrical panel and the furnace’s power switch often looks like a light switch near the unit. Inspect the unit for any loose or damaged wiring. Reset tripped breakers or replace fuses if safe. If the breaker keeps tripping, call a technician immediately as this could signal an electrical fault.
Gas Supply Issues
If your furnace runs on natural gas or propane, a supply issue will keep it from starting. Some common problem may include closed gas valve, empty propane tank or a gas line issue. If you smell gas, leave your home immediately and call your utility company or emergency services. Don’t try to restart the furnace yourself.
Pilot Light or Ignition Failure
Older gas furnaces use a pilot light, while newer ones use electronic igniters. If either fails, your furnace will not start. Relight the pilot light if it’s out, following manufacturer instructions. For electronic igniters, call a technician they are delicate components that need professional attention.
Clogged Air Filter
A severely clogged air filter can block airflow and cause the furnace to overheat and shut down before it starts properly. Check and replace your air filter every 1 to 3 months during heating season.
Safety Switches & Sensors
Furnaces have built-in safety switches like limit switches, pressure switches, and flame sensors that shut the system down if they detect an unsafe condition. These safety features should only be inspected and repaired by an HVAC professional.
Blocked Vents or Exhaust Pipes
High-efficiency furnaces have intake and exhaust pipes that vent outside. If these become blocked by snow, ice, or debris, the furnace may lock out and refuse to start. Carefully clear any obstructions from exterior vents to restore airflow.
When to Call a Professional HVAC Contractor
If you have checked the basics such as the power, gas supply, and air filter and your furnace still will not start, it is time to call a qualified HVAC technician. Issues like ignition system failure, damaged motors, or faulty safety switches require expert diagnosis and repair.
Emergency Heating Repair, Maintenance, Installation & More in Carmel, Pebble Beach, Seaside & Greater Monterey, California
A furnace that will not start does not always mean a major breakdown. By understanding the most common causes, you can troubleshoot quickly and know when to call in the pros. Prompt attention can save you from bigger repairs and keep your home warm all winter. If you need help heating your home this winter season, contact Monterey Peninsula Sheet Metal & Heating and schedule our services today.
