Emergency Gas Boiler Repair on Long Island
Last updated Reviewed by Waseem Shahzad, Lead Technician
A gas boiler that will not fire, keeps locking out or runs while the house stays cold usually has a failed ignition or flame part, a venting or draft problem, a stopped circulator, or low water pressure. If you smell gas, leave the house and call 911 and National Grid at 1-800-490-0045 from outside first.
Call 24/7: (631) 414-7141Smell gas or hear a carbon monoxide alarm? Leave the house first, then call 911 or the gas utility from outside.
Why does a gas boiler stop heating?
Common causes are a pilot or ignitor that will not light, a failed flame sensor or thermocouple, a draft or flue motor that stopped, a tripped rollout or limit switch, a circulator pump that quit, low system pressure, or a thermostat or zone valve that is not calling.
- Ignition: pilot assembly, ignitor, thermocouple or flame sensor.
- Venting: a flue or draft motor that failed, or a blocked vent.
- Safety switches: rollout, limit or pressure switches that open and stop the burner.
- Water side: a circulator that quit, low pressure, air in the loops or a failed expansion tank.
What can you safely check yourself?
Set the thermostat to Heat above room temperature, check the boiler's service switch and breaker, and read the pressure gauge. If the boiler has a lockout reset or an error display, note the code and press reset once. If it locks out again, stop and call. Never jump a switch.
A pressure gauge near zero means the boiler is low on water; see our boiler pressure guide. If only some rooms are cold, see baseboard heat not working in one room.
When should you stop and call right away?
Call when the boiler locks out again after one reset, you hear banging, grinding or clinking at startup, water is leaking or the relief valve is discharging, a rollout switch keeps tripping, or the house is cooling in freezing weather. For gas smell or a CO alarm, leave first and call from outside.
- Gas smell or CO alarm: see what to do first.
- Leaks: see boiler leaking water.
- No hot water too: see no hot water.
What does K2 do on a gas boiler no-heat call?
We check gas supply and venting first, then ignition, the flame sensor, safety switches, the draft motor, circulators, zone valves and pressure. You get the cause and the price before any repair, and we run the boiler through full cycles before we leave.
In Hauppauge we replaced a failed flue motor on a boiler that kept shutting off and needed a reset, and on an earlier call at the same home replaced its temperature sensor, pilot assembly and rollout switch. See Hauppauge boiler repair, the East Islip no-heat repair and boiler repair.
Recent no-heat calls we fixed
No heat: expansion tank, relief valve and circulator replaced
East Islip · Heating Repair · October 2026
A new customer with no heat. We replaced the air bleeder, expansion tank, relief valve and circulator pump and tuned up the system.
One of three boiler zones not heating
Dix Hills · Boiler Repair · October 2026
A three-zone gas boiler with one cold zone. We bled the air from all three zones, replaced the air bleeder and four caps, and cleaned the boiler.
Questions people ask
Why does my gas boiler make a clinking noise when it starts?
A failing draft or flue motor is a common cause, especially if the boiler also shuts off and needs a reset. Kettling or banging in the pipes can also come from scale or air. Have it checked rather than resetting it repeatedly.
Is it safe to relight a boiler pilot?
On a standing-pilot boiler, you can follow the lighting instructions on the boiler label. If it will not stay lit, or you smell gas, stop. A pilot that keeps going out usually needs a new thermocouple or pilot assembly.
My boiler runs but the house is cold. Why?
The burner can fire while the heat never reaches the rooms if a circulator pump stopped, a zone valve is stuck, the system is low on water or air is trapped in the loops. Those are common no-heat calls with a running boiler.
Need help now?
K2 answers 24/7 for homes within 15 miles of our shop at 60 S 2nd St, Unit V, Deer Park. You get a time window and the price before any repair.
Call 24/7: (631) 414-7141