The Short Answer
- 01Book a professional service every year, before the heat season. Most manufacturers tie the warranty to it, and it's where combustion and safety controls get tested.
- 02Steam boilers: check the water level in the sight glass and blow down a float-type low-water cutoff weekly during the heat season. New steam boilers also need skimming in the first weeks to clear oil from the piping.
- 03Hot-water boilers: check the pressure gauge stays in the range your installer marked, and look for drips at the relief valve and fittings.
- 04Keep a service log with the installation date, every visit, and every repair. Warranty claims and DOB inspections both go faster with it.
- 05Leave the burner, gas valve, venting, and safety controls to a licensed tech. If you smell gas, get out and call 911 or your utility from outside.
In This Guide
01
The First Year, Step by Step
Most of a new boiler's problems show up early: oil and debris from the new piping, air in a hot-water system, a control that needs adjusting. This is the schedule we give owners at handover, for homes and buildings alike.
- 1
Handover Day
Walk the boiler with the installer. Find the emergency switch, the gas shutoff, the water fill valve, and the low-water cutoff. Ask them to mark the normal pressure or water level on the gauge, and keep the manual, the warranty card, and the installation date together.
- 2
First Week
Check the boiler daily. On steam, watch the sight glass: a new boiler can surge or bounce while oil from the piping cooks off. On hot water, watch the pressure as air works out of the system. Write down anything that changes.
- 3
First Month
Steam boilers usually need one or more skimmings to clear that oil, and a follow-up visit to check the water and the low-water cutoff. Hot-water systems may need the air vents checked and the pressure topped up once the air is out. Register the warranty if the manufacturer offers it.
- 4
Every Heat Season
Walk the boiler room once a month: water level or pressure, any leaks, anything stored near the boiler, and alarms tested. On steam, blow down a float-type low-water cutoff weekly.
- 5
Every Year
A professional service before the heat season: cleaning, combustion test, and safety controls. Buildings with six or more units, and every commercial or mixed-use building, also owe the annual DOB boiler inspection.
02
Steam vs. Hot Water: What to Check
Steam and hot-water boilers need different checks. If you're not sure which you have, look at the gauge: a sight glass with water in it means steam, a single pressure and temperature dial means hot water.
- Water level or pressure
- Steam boilerAt the water line marked on the boiler, usually about half the glass
- Hot-water boilerPressure in the range marked at install
- Low-water cutoff, float type
- Steam boilerBlow down in seasonWeekly
- Hot-water boilerTested at the annual service
- Low-water cutoff, probe type
- Steam boilerNo blowdown; tested at the annual service
- Hot-water boilerTested at the annual service
- Automatic water feeder
- Steam boilerNote how often it adds water; frequent filling points to a leak
- Hot-water boilerSame; a system that keeps needing water has a leak
- Relief valve
- Steam boilerLook for drips or steam at the discharge pipe
- Hot-water boilerLook for drips at the discharge pipe
- Air vents and radiators
- Steam boilerRadiator vents hissing then closing, no water spitting
- Hot-water boilerBleed radiators or baseboard that stay cold at the top
- Condensate drain
- Steam boilerNot applicable
- Hot-water boilerCondensing boilers only: drain and neutralizer flowing, no backup
03
What an Owner or Super Can Do
None of these need tools or a license, and together they catch most problems before they become a no-heat call.
- Keep three feet clear around the boiler. Boiler rooms aren't storage, and paint, cleaners, and laundry chemicals near a burner are a fire risk and can corrode the boiler.
- Keep combustion air openings and louvers open. A boiler starved of air burns dirty and can make carbon monoxide.
- Test carbon monoxide and natural gas alarms monthly with the test button. See our natural gas detector guide for where alarms are required.
- Look under and around the boiler for water, rust streaks, or soot, and listen for new banging, whistling, or short cycling.
- Watch the fuel bill and the water meter. A jump in either can point to a leak or a control problem.
- Write every check, blowdown, and repair in the service log.
04
What the Annual Service Covers
The annual service is where the boiler gets opened up and tested. Exact steps depend on the model, but a proper visit covers these.
- Clean the burner and heat exchanger
- Why it mattersSoot and scale waste fuel and overheat the boiler
- Combustion analysis
- Why it mattersMeasures carbon monoxide and efficiency, and sets the burner
- Test the low-water cutoff, relief valve, and limits
- Why it mattersThese are what shut the boiler down safely
- Check the venting and chimney connection
- Why it mattersFlue gases have to leave the building
- Check gas pressure and the gas valve
- Why it mattersLow or high pressure causes poor combustion
- Flush the condensate trap and check the neutralizer
- Why it mattersCondensing boilers only; a blocked trap shuts the boiler down
- Check water quality and inhibitor
- Why it mattersMany hot-water boilers need treated water to protect the heat exchanger
Our boiler tune-up and startup covers all of this with a written report. A maintenance plan puts it on our schedule every fall, so nobody has to remember.
05
Protecting the Warranty
We install many brands, and each one's warranty reads differently, but the conditions look alike. Burnham's K2 manual says the warranty doesn't cover damage if the listed maintenance isn't done on schedule, with annual service by a technician. Navien excludes improper maintenance, scale, and water quality damage. Weil-McLain excludes lack of maintenance and installation not done to its instructions by a qualified contractor.
- Annual service by a qualified, licensed technician, with a dated record of what was done.
- Water within the manufacturer's limits. Hard or untreated water and repeated fresh makeup water from an unfixed leak are common reasons for denied heat exchanger claims.
- No freezing. Damage from a boiler left off in a cold building isn't covered.
- Repairs with the manufacturer's parts, done by someone licensed for the work.
- Proof of the installation date. Keep the invoice; registration helps but usually isn't required.
06
Extra Steps for Multifamily and Commercial Buildings
A building boiler has the same needs as a home boiler, plus compliance dates and more people who may touch it.
- DOB inspection: residential buildings with six or more units, and all commercial and mixed-use buildings, need a boiler inspection every calendar year. See our boiler inspection guide for deadlines and penalties.
- One person owns the log. The super or managing agent keeps the service log at the boiler, so the inspector, the warranty, and the next tech all see the same history.
- Lock the boiler room and limit who can change settings. A setting changed by someone untrained is one of the most common causes of trouble on a new boiler.
- Plan around the gas piping cycle. Local Law 152 inspections can line up with the boiler service. See Local Law 152 deadlines.
07
When to Call Right Away
Shut the boiler off with the emergency switch and call us if you see any of these.
- Water leaking from the boiler, or the relief valve discharging
- An empty sight glass, or a hot-water pressure gauge far outside its marked range
- Soot around the burner door or vent, or a carbon monoxide alarm
- The burner starting and stopping every few minutes, or loud banging
- No heat, or a reset button that keeps tripping
08
Common Questions
How often does a new boiler need maintenance?
A professional service once a year, before the heat season, plus owner checks: weekly low-water cutoff blowdown on most steam boilers, and a monthly look at the water level or pressure during the heat season.
Does a new boiler need servicing in its first year?
Yes. Most manufacturers want annual service from the start, and new steam boilers usually need skimming in the first weeks to clear oil from the new piping.
Will skipping the annual service void my boiler warranty?
It can. Most manufacturers exclude damage from lack of maintenance, and Burnham's manuals tie coverage to annual service by a technician. Keep a dated record of every visit.
How often should I blow down the low-water cutoff?
Weekly during the heat season for float-type cutoffs on steam boilers, and more often on a new boiler. Probe-type cutoffs don't have a blowdown and are tested at the annual service. Follow the instructions on your control.
What pressure should my hot-water boiler be at?
It depends on the building's height. Ask the installer to mark the normal range on the gauge, and call if it climbs toward the relief valve rating or keeps dropping.
Is the annual service the same as the DOB boiler inspection?
No. The service is maintenance every boiler needs. The DOB inspection is a compliance filing for buildings with six or more units, and commercial and mixed-use buildings. We can do both in one visit.
Sources
- Burnham K2 Installation, Operating & Service Manual: Annual Inspections and Service
- Navien NFC Limited Warranty
- Weil-McLain Commercial Cast Iron Boiler Limited Warranty
- McDonnell & Miller (Xylem) Boiler Controls Catalog
- NYC DOB: Boiler Compliance
This guide explains NYC rules in plain terms. It isn't legal advice, and rules and utility procedures change; check the sources above or call us about your building.