Wilmington HVAC guide

Fall Boiler Startup Checklist for Landlords and Homeowners

A pre-season checklist for steam and hot-water boilers: water level, pressure, vents, burners, CO alarms, and when to book service.

Close-up of glass sight gauge column and low water cutoff valve on residential steam boiler in historic Wilmington home Fall Startup Checklist
Short answer

Before the first cold night, check the boiler water level (steam) or pressure (hot water), look for leaks, confirm radiator vents and valves work, test carbon-monoxide alarms, and book annual service, especially for oil. Fire the system on a mild day so problems appear before you need the heat.

Digital electronic combustion analyzer testing furnace flue gas temperatures and carbon monoxide levels Technical Consideration
Bleeding radiators, checking boiler sight glass water levels, and testing burner combustion.

Fall startup checklist

Fall startup checklist
CheckSteamHot water
Water level / pressureSight glass about half fullTypically 12–20 psi cold
VentsRadiator and main vents open and clearBleed air from radiators
LeaksCheck fittings and returnsCheck valves, tank, and pump
SafetyTest low water cutoff (per manual)Check relief valve for drips
AlarmsTest CO and smoke alarmsTest CO and smoke alarms

When should I start the boiler?

On a mild day in September or October, before heat is essential.

That leaves time to get parts if something fails.

What should a service visit include?

Burner cleaning and adjustment, combustion testing, safety control checks, and for oil, nozzle and filter replacement.

Annual boiler maintenance typically runs about $200 to $500.

What should landlords document?

Service dates, CO alarm tests, and tenant notices.

Records help with rental inspections and liability.

Related services in Wilmington

Local verification resources

Before authorizing work, use the Delaware license lookup. For projects that may require approval, consult the City of Wilmington permit information or the authority serving the property.

Keep reading

About this guide

Wilmington Climate Pros Editorial Team — Guides are researched from manufacturer documentation, published cost data, Delaware program rules, and local building conditions. They are educational and do not replace an on-site diagnosis by a qualified, licensed provider.

Common questions

Clear answers before you call

Should I drain my steam boiler?

Flushing the low water cutoff is often recommended on some models; follow the manufacturer instructions or have it serviced.

My radiators are cold on the top floor. Why?

On hot water, usually air; on steam, often failed vents or pipe pitch problems.

Ready to request help?

Tell us what your HVAC system is doing.

Call any time or send the service request form. For gas odor, smoke, fire, or a carbon-monoxide alarm, leave the property and contact emergency services or the utility first.

Call now: (302) 412-8942