BoilerTroubleshooting2026-02-26
Boiler Cycling On and Off Too Often
Short-cycling wastes gas and wears the boiler — usually airflow, sizing or a sensor.
A boiler that switches on and off too frequently is short-cycling, which shortens its life.
Common causes
An oversized boiler, poor circulation, a faulty thermistor, or a thermostat placement issue cause short-cycling.
What to do
Check thermostat placement and pressure; persistent short-cycling needs a circulation and sensor check, and correct sizing at replacement.
Key takeaways
- Short-cycling wastes gas
- Often oversizing or circulation
- Check thermostat placement
- Right-size at replacement
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