Short answer
High-efficiency furnaces draw air and vent exhaust through PVC pipes on an outside wall. Drifting snow can block them, and the furnace shuts down for safety. After a storm, gently clear snow and ice from both pipes, then reset the thermostat. If it still will not run, call a technician.
Find your pipes
Look for two white PVC pipes exiting the house near the furnace location, sometimes on the roof.
Clear them safely
Brush away snow by hand. Do not use a shovel on the pipes or chip ice with tools.
Not sure it is safe to keep running? A local technician can check it today.
Call NowRestart
Turn the thermostat off for a few minutes, then back on. Some furnaces need a power cycle at the switch.
Prevent it
Keep the area clear during storms and avoid piling plowed snow there.
Related questions
Is a blocked vent dangerous?
The furnace's pressure switch shuts it down, but keep CO detectors working.
Can I extend the pipes?
Only a technician should modify venting.
Services that fix this
Emergency Heating Repair
No heat on a cold night, CO alarms and furnaces that will not restart.
Emergency heating repair in MarlboroughFurnace Repair
Gas and oil furnaces that will not heat, blow cold, short-cycle or make noise.
Furnace repair in MarlboroughThis guide is general information for homeowners, not a diagnosis of your system. For anything involving gas, carbon monoxide, electricity or active leaks, stop and call a qualified professional.
