Few things are more upsetting than turning on your heating system on a cold day, only to find it will not start. Whether you rely on a furnace, boiler, or heat pump, a system that won’t turn on can leave your home uncomfortable and unsafe in freezing weather. The good news? Many heating issues have common causes that can be identified and fixed quickly some by homeowners and others by a professional. Absolute P&M Services would like to take a look at why a heating system will not start and what you can do about it.
Power Supply Problems
Your heating system can’t run without power. A tripped breaker or blown fuse is a common reason furnaces and boilers will not start. You will what to check:
• Circuit breaker panel for tripped switches
• On/off switch near the furnace or boiler
• Blown fuses in the main panel
Reset the breaker or replace the fuse if it is safe to do so. If it trips repeatedly, call an HVAC technician as this may signal an electrical problem.
Pilot Light or Ignition Failure
For gas furnaces and boilers, the pilot light or ignition system is crucial. If it fails, the burners won’t ignite. Common causes can include the following:
• Extinguished pilot light
• Faulty electronic ignition system
• Dirty flame sensor
Relight the pilot light if your unit uses one and follow the manufacturer’s instructions. If it keeps going out, call a professional as this may indicate a faulty thermocouple or gas valve.
Gas Supply Issues
If your heating system uses natural gas or propane, any disruption in supply will prevent startup. Some common potential problems are:
• Closed or faulty gas valve
• Empty propane tank
• Gas line issues
If you smell gas, evacuate immediately and call your utility company or emergency services. Do not attempt to relight or repair the system yourself.
Clogged Air Filter
A severely clogged air filter can restrict airflow so much that the furnace overheats and shuts down before it even starts properly. Check and replace your air filter every 1 to 3 months, especially during peak heating season.
Safety Switches or Sensors
Heating systems are equipped with safety switches and sensors to prevent dangerous operation. If one fails or correctly detects a problem, the system won’t start. Some common examples include:
• Limit switch detecting overheating
• Pressure switch in furnaces
• Flame rollout or draft safety switches
These require professional diagnosis and repair. Do not bypass or disable safety controls.
Mechanical or Motor Failures
If the blower motor, inducer motor, or other internal components fail, your heating system may not start or may shut down quickly after trying. A professional technician can test, repair, or replace failing motors and parts.
Furnace & Boiler Heating Maintenance, Repairs, Replacement & More in Santa Fe, Tomball, Sugar Land, Galveston, Austin & Greater Houston, Texas
A heating system that will not start is stressful, but understanding the most common causes can help you troubleshoot quickly. If your heating system will not start or won’t heat your home properly, contact Absolute P&M Services and schedule our services today.
