What is likely happening
The low-water cutoff shuts the burner off when water drops too low, protecting the boiler from dry firing. Repeated trips usually mean water is being lost somewhere (a leak, a steam trap, a relief valve) or the cutoff itself is fouled.
What you can safely check
- Check whether the sight glass (on steam boilers) shows water.
- Look for leaks, open drains, or failed steam traps.
- Note whether an automatic feeder is adding water often.
What an inspector will look at
- Low-water cutoff testing and blowdown
- Feed water system
- Steam traps and returns
- Leak tracing
Does this affect compliance?
Low-water cutoff operation is tested at required boiler inspections. A cutoff that does not work is a serious defect.
When it becomes urgent
Do not bypass or jumper the cutoff. If the boiler has run dry, do not add cold water to a hot boiler; shut it down and call for service.
We can help with this
Boiler inspection is something Insparisk does nationwide. To see the local rules for your building, open this in the interactive Problem Solver.
Request boiler inspectionTalk to an advisorGeneral guidance only, not a substitute for a licensed inspection or emergency services. For any gas odor, carbon monoxide alarm, fire, or trapped occupant, call 911 first.