⚠️ Furnace Short Cycling? (416) 424-4328 — Same-Day Furnace Repair Scarborough
Furnace Short Cycling — Causes & Fixes for Scarborough Homeowners
Short cycling means your furnace turns on, runs briefly (30 seconds to 2 minutes), shuts off, then repeats. It never completes a full heating cycle, leaving your home cold.
Causes of Furnace Short Cycling (Most Common to Least)
- Dirty flame sensor — #1 cause. Furnace lights but flame sensor cannot confirm flame; shuts off after 7 seconds. Clean ($150–$250) or replace ($200–$300).
- Clogged filter — Restricted airflow causes high limit switch to trip on high temperature. Replace filter first.
- Failed high limit switch — Trips too easily even at normal temperatures. Replacement: $200–$350.
- Oversized furnace — Heats room too fast, satisfies thermostat before completing cycle. Solution: proper right-sizing on replacement.
- Failed pressure switch — Draft/pressure issue. Replacement: $200–$350.
Why does my furnace keep short cycling in Scarborough?
The most common cause of furnace short cycling in Scarborough is a dirty flame sensor. Other causes: clogged filter, failed high limit switch, oversized furnace, or pressure switch failure. Start by replacing the filter. If it continues, call Madina Mechanical at (416) 424-4328 for same-day furnace diagnosis.
