Start With the Safe Basics

Confirm the thermostat is set to heat, the temperature setting is above the room temperature, and fresh batteries are installed if your thermostat uses them. Check that the furnace switch is on and the breaker has not tripped.

Check Airflow

A badly clogged filter can restrict airflow enough to trigger safety controls. Replace the filter if it is dirty, then make sure supply and return vents are open and not blocked by furniture, boxes, or rugs.

Look at the Intake and Exhaust

High-efficiency furnaces often have exterior intake and exhaust pipes. Snow, ice, leaves, or debris around those pipes can stop the furnace from running. Clear the area gently and never push objects deep into the piping.

Do Not Bypass Safety Controls

If the furnace starts and shuts down again, shows repeated error codes, smells like gas, makes unusual sounds, or will not ignite, stop troubleshooting. Safety controls are there to protect the home.

When to Call ER Plumbing & Heating

Call for furnace service when the unit will not start after basic checks, heat is uneven, the blower keeps cycling, the flame is unstable, or the furnace is older and struggling during cold weather.