Long Island loses power in nor'easters, ice storms and the occasional summer squall, and a winter outage brings a second worry: when the lights come back, will the heat? Most boilers start again on their own, but some don't, and the reason is usually simple. Here's what a power outage does to a boiler, the safe checks you can make yourself, the things you should never do, and when to stop and call.
Why does a boiler stop during a power outage?
Almost every modern boiler needs electricity to run. The burner, the ignition, the controls, the circulator pumps that move hot water to the baseboards and the draft or vent motor all run on house power. When the power goes out, the boiler stops, even though the gas or oil supply is still there.
Some older gas boilers with a standing pilot keep that small flame lit through an outage, because the pilot's safety circuit makes its own tiny current. That doesn't mean heat: without power, the controls can't open the main gas valve and the circulators can't move water. A few very old gravity hot-water and steam systems are the exception, and they are rare in Long Island homes today.
What should you check when the power comes back?
Start with the thermostat. Many digital and Wi-Fi thermostats reboot after an outage and may come back set to off, the wrong mode or a default schedule, and battery models may have dead batteries. Set it to heat and a few degrees above room temperature, then give the boiler a few minutes to respond.
If nothing happens, check the boiler's service switch, often a red-plated switch at the top of the basement stairs or on the boiler itself, and make sure it's on. Then check the circuit breaker for the boiler in your panel. Breakers sometimes trip when power returns with a surge. If you heat with oil, look at the tank gauge, since outages often come with storms that delay deliveries.
Is it safe to press the boiler's reset button?
Once, yes. Oil burners have a reset button on the primary control, and many gas boilers have a lockout reset on the control panel. If the burner tried to fire during a brownout or the moment power returned, it may have locked out. One press can clear that. If it locks out again, stop and call.
Pressing reset again and again on an oil burner can pump unburned oil into the combustion chamber, which can cause a puff-back of smoke and soot or worse when it finally lights. Our guide to the oil burner reset button covers what it does and what to check first. On gas boilers with a display, write down any error code before resetting; it tells the technician where to look.
What does a reset fix and what doesn't it fix?
A reset clears a lockout; it doesn't repair a failing part. If the boiler only locked out because the power dropped, one reset is all it needs. If it locked out because a sensor, motor or safety switch is failing, it will run for a while and then stop again, sometimes for days. Repeated lockouts always mean a real problem.
Our records show that pattern. In April 2025 in Hauppauge, a no-heat call found a failing temperature sensor, pilot assembly and flame rollout switch; cleaning and a reset got the heat back for the night, and we replaced all three parts the next day. In February 2026 at another Hauppauge home, a boiler that kept shutting off and needed a reset to start, with a clinking noise, had a failed flue motor, which we replaced. Neither call was caused by an outage, but both show why a boiler that needs a second reset needs a technician.
What else can stop a boiler from restarting?
A tripped low-water cutoff, a control that needs resetting, a failed flame sensor or a damaged control board are the usual causes after the basic checks. Some low-water cutoffs have their own manual reset button. A surge when power returns can also damage the control board, ignition module or thermostat, leaving the boiler with no lights at all.
In March 2026 in Huntington, a no-heat call found the boiler's temperature control setting needed to be reset, and a filter next to the boiler was extremely dirty; our technician cleaned the filter, reset the control and restarted the boiler. On oil burners, the cad cell is the flame sensor that tells the control the burner lit, and a dirty or failed one causes lockouts; we replaced a cad cell and a solenoid valve during a Bay Shore oil burner tune-up in November 2025.
What should you never do after an outage?
Don't keep pressing reset, open the burner or control panels, jump or bypass safety switches, or try to light a burner by hand. Don't heat the house with a gas oven or stove, and never run a generator, grill or camp heater indoors or in a garage. Those cause fires and carbon monoxide poisoning.
If you smell gas, leave the house and call the gas utility from outside. If you smell oil smoke or see soot around the boiler, turn the service switch off and call. Make sure your carbon monoxide alarms have working batteries before an outage; our post on carbon monoxide and your heating system covers where they belong.
Can you run a boiler on a generator?
Yes, if a licensed electrician installs a transfer switch or generator inlet that safely connects the boiler circuit. Never plug a generator into a wall outlet to feed house wiring, which can send power back onto utility lines and injure line workers. Run any portable generator outdoors, at least 20 feet from the house, as the CPSC advises.
A boiler doesn't need much power compared with central air, so a modest generator can usually run it, along with the circulators. Some boiler controls are sensitive to the uneven power from inexpensive generators, so check the boiler maker's guidance. If outages are common on your street, have the boiler circuit planned for a generator before the next storm, not during it.
When should you call for service?
Call when the thermostat, service switch, breaker and fuel all check out and the boiler still won't run, when it locks out again after one reset, when there are no lights or display at all, or when you smell gas, oil smoke or exhaust. Call sooner if the outage was long and the house is getting cold.
A long outage in freezing weather also puts pipes at risk; our post on keeping boiler and baseboard pipes from freezing covers what to do while you wait. K2 answers the phone around the clock at (631) 414-7141 for homes within 15 miles of Deer Park. See our boiler repair service, the no-heat page, a Huntington Station oil boiler tune-up and our overview of boiler repair across Long Island.
Need a technician rather than a guide? See our boiler repair service, or read about HVAC repair in Hauppauge, NY. K2 answers 24/7 at (631) 414-7141.
