Heating maintenance before the season starts: what a pre-season service includes, and what it saves you

By GW Mechanical Corp. Published October 21, 2026. About a 7 minute read.

Heat season in New York City starts October 1, and the first cold night finds every weak point in a heating system at once. A pre-season maintenance service is a scheduled visit, before that night, in which a licensed plumber cleans, tests and adjusts the equipment so it runs through the winter without a call at 2 a.m. This is what GW Mechanical Corp does on that visit in Brooklyn, Queens, Staten Island and Manhattan, what you should do alongside it, and why it pays for itself.

What the pre-season service includes

A proper service is not a technician glancing at the flame and leaving a sticker. Each item below is on our worksheet, and you get the completed sheet with readings and photos.

1. Boiler tune-up

• Burners and heat exchanger cleaned. A summer of dust and rust flakes causes delayed ignition, yellow flame and soot. Cleaning restores a clean blue flame and full heat transfer.
• Ignition checked. Pilot, thermocouple, igniter and flame sensor, whichever the boiler uses. A dirty flame sensor is the single most common cause of a boiler that lights and shuts down.
• Combustion test. An analyzer at the flue reads oxygen, carbon monoxide and stack temperature. This proves the boiler is burning cleanly and venting, and catches a cracked heat exchanger before it becomes a carbon monoxide problem.
• Flue and chimney connection inspected for rust holes, loose joints and blockage.
• Gas pressure and gas valve checked, every joint tested with an electronic leak detector.

2. Safety controls tested, not just looked at

• High-limit and rollout switches tripped and reset to confirm they work.
• Pressure relief valve lifted and reseated; replaced if it drips afterward.
• Low-water cutoff on steam boilers flushed and tested; this is the device that keeps a boiler from running dry and cracking.
• Carbon monoxide check in the boiler room and at the nearest living space with the boiler running.

3. The water side of the system

• Hot water boilers: system pressure checked cold (typically 12 to 15 psi), expansion tank air charge tested and the tank replaced if waterlogged, circulator pumps and zone valves run, air bled from the loop.
• Steam boilers: sight glass cleaned so the level can be read, automatic feeder checked, pigtail under the pressure control cleaned, main vents and radiator vents checked, boiler skimmed if the water surges.
• Water heater: sediment flushed, temperature and pressure relief valve tested, anode rod checked on tanks over three years old, setpoint confirmed at 120°F at the tap. Indirect tanks get their coil and zone checked with the boiler.

4. Thermostat batteries in every room of the house

This is the item most people skip, and it is the most common no-heat call we take that involves no broken part. Many thermostats, including most programmable and many smart models, run on AA or AAA batteries or rely on them as a backup. When the batteries fade in October, the display dims or goes blank, the schedule is lost, or the thermostat simply stops sending the signal that tells the boiler to run. The boiler is fine; the house is cold.

On the pre-season visit we replace the batteries in every thermostat in the building, not just the one in the hallway. A three-family house in Queens can have six thermostats; a zoned Brooklyn brownstone often has four. One dead thermostat leaves one floor cold while the rest of the house is fine, which is confusing to diagnose at midnight and trivial to prevent in the afternoon. We use fresh alkaline batteries (rechargeables run at a lower voltage and trigger low-battery behavior early), confirm each thermostat calls for heat and the right zone responds, restore any schedule that was lost over the summer, and reconnect smart thermostats that dropped off Wi-Fi.

While we have a ladder out, we also change the batteries in the smoke and carbon monoxide alarms and check the manufacture dates; CO alarms wear out after five to ten years and should be replaced, not just re-batteried. NYC requires both in every home and apartment.

5. Distribution and the parts outside

• Radiators bled on hot water systems; pitch and vents checked on steam radiators.
• Exposed pipes in unheated spaces insulated; outdoor spigots shut off and drained.
• Side-wall vent terminations on high-efficiency boilers cleared, and the condensate drain and neutralizer checked, because a frozen or blocked condensate line will shut a condensing boiler down.

The benefits, in order of how much they matter

Benefit 1: No emergency call in the first cold week

This is the one that justifies the visit on its own. In the first cold week of the season, every plumber in the city is on no-heat calls and supply houses run short of common parts. A problem found in October is a scheduled repair with parts in hand. The same problem found in December is a wait, in a cold building, and for a landlord it is an HPD Class C violation accruing daily penalties. Nearly every winter no-heat call we take traces back to something a pre-season visit would have caught: a flame sensor, a dead thermostat, a waterlogged expansion tank, a stuck low-water cutoff, a snow-blocked vent.

Benefit 2: Longer equipment life

A boiler that is cleaned and combustion-tested every year commonly reaches 20 to 25 years; one that is never serviced often fails at 12 to 15. A tank water heater flushed yearly with its anode checked reaches its 10 to 12 year design life instead of failing at 6 or 7. An expansion tank replaced when it waterlogs protects the boiler, the water heater and the relief valve from pressure cycling. The service costs a fraction of a year of equipment life.

Benefit 3: Lower gas and electric bills

A clean burner with correct combustion uses less gas for the same heat. A water heater without a layer of sediment heats faster. A circulator that is not fighting air moves water with less electricity. The savings are modest for a small home and significant for a building, and they show up on the first winter bill.

Benefit 4: Safety you can prove

The combustion test, the CO check and the safety-control tests are documented with readings. For a homeowner that is peace of mind. For a landlord it is the record that shows the system was inspected by a licensed master plumber before the season, which matters if a complaint or an insurance claim ever arrives.

Benefit 5: Priority when something does fail

Members of our annual maintenance plan get the pre-season visit scheduled automatically each fall and priority dispatch in winter. When a part does fail in the busiest week of January, you are at the front of the line, not behind thirty no-heat calls.

When to book it

September is ideal and October is still good. By November the first cold snap has usually arrived and the visit becomes a repair call. If the boiler is already past twenty years, or the last service turned up a cracked heat exchanger or repeated lockouts, it is worth reading our guide on repair versus replacement before the season rather than during it.

For the full room-by-room list, including the items you can do yourself in an afternoon, see the winter heating maintenance checklist. To book a pre-season service in Brooklyn, Queens, Staten Island or Manhattan, call 646-980-2411 or schedule a visit online.

Questions

Related: Maintenance plans · Boiler repair · Hot water tank replacement