What Homeowners Can Check
Monthly
- Check the pressure gauge — Hot water boilers should read 12–25 psi when cold. Steam boilers should read 0.5–2 psi during operation. If pressure is outside these ranges, call a technician.
- Check the sight glass (steam boilers) — The water level should be visible in the middle of the sight glass. If it's low, the system needs water. If it's consistently low, there may be a leak.
- Listen for unusual noises — Banging, gurgling, or hissing are signs something needs attention.
Seasonally (Before Heating Season)
- Test the pressure relief valve — lift the lever briefly to make sure it opens and closes freely
- Bleed radiators (hot water systems) — release trapped air from each radiator using a bleed key
- Check that all radiators are heating evenly
- Inspect visible pipes for corrosion or leaks
Annual Professional Service
Once a year, have a technician perform a full boiler tune-up. This includes:
- Cleaning the heat exchanger and burners
- Testing combustion efficiency
- Inspecting the flue and venting
- Checking all safety controls
- Testing the pressure relief valve
- Inspecting the expansion tank (hot water systems)
- Checking the circulator pump (hot water systems)
When to Call Immediately
Call for service right away if you smell gas near the boiler, see water pooling on the floor, notice the pressure relief valve discharging continuously, or the boiler fails to ignite.