The boiler fires, runs for a short time, and shuts off before the house is warm. If you smell gas, leave the house. If you do not, stop pressing reset.
A burner that will not stay lit is a repair, not a setting on the thermostat. Book boiler and furnace repair, or request service and say the boiler turns on and then off.
First safe step
Smell gas, or hear a hiss at a gas line? Leave and use what to do if you smell gas. No gas smell? Leave the reset button alone after one try, and book repair.
1What you are seeing
Short cycling means the burner starts and then stops on its own, often every few minutes. The radiators never get a long enough run to heat the rooms. The thermostat can be calling for heat the whole time.
That is different from a boiler that never lights, a boiler that makes hot water but no heat, or a boiler that loses pressure and sits cold. Those have their own pages. This one is only the boiler that lights and then quits.
2What to do before you call
Do this, then stop:
- If you smell gas, leave. Do not look for the leak and do not reset the boiler.
- If you do not smell gas, look at the boiler once. Note a lockout light, a blinking code, or a pressure needle sitting at the bottom of the gauge.
- Press reset one time only. If it fires and shuts off again, leave it.
- Tell the technician how long it runs before it stops, and whether the radiators got warm at all.
Do not keep resetting it
A lockout is the boiler refusing to keep the flame going. Clearing it over and over does not repair the flame sensor, the water level, or the control. It also erases the clue the technician uses.
3If the symptom is different
Use the page that matches what the boiler is actually doing. Each of those visits is booked on its own page.
- •Hot water at the tap, but the rooms stay cold: hot water but no heat.
- •The gauge keeps falling: boiler keeps losing pressure.
- •You smell gas: what to do if you smell gas.
Book the repair
Boiler repair stays on the repair page. This page only explains the shutoff and sends you there.
- 1Boiler and furnace repair: the burner lights and then shuts off.
- 2Request service or call (774) 226-6062: say it short-cycles, and mention any lockout light you saw. Shop hours are Monday–Friday, 7:30 AM–4:00 PM, Saturday by appointment.
Boiler short-cycling FAQs
What does it mean if my boiler turns on and then shuts off?
The burner is lighting and then stopping before the house is warm. That can be a safety lockout, low water, or a control that is not happy with the flame. It is a repair visit, not a thermostat tweak.
What should I do first if the boiler keeps shutting off?
If you smell gas, leave the house and follow the gas-smell steps. If you do not smell gas, stop pressing reset. Note whether it runs for a minute and then stops, then book boiler repair.
Should I keep resetting a boiler that short-cycles?
No. One reset is enough to see if it stays lit. Resetting it over and over does not fix a lockout, and it can hide the fault the technician needs to see.
Where do I book boiler repair for a boiler that will not stay on?
Use the boiler and furnace repair page, then request service. Say that the boiler fires and then shuts off. Shop hours are Monday through Friday, 7:30 AM to 4:00 PM, Saturday by appointment.