Emergency Oil Boiler Repair on Long Island
Last updated Reviewed by Waseem Shahzad, Lead Technician
An oil boiler that stops on a cold night is usually out of oil, locked out on its safety control, or held up by a clogged filter, nozzle or a failed part. A few checks are safe to do yourself. If they do not bring the heat back, call (631) 414-7141. K2 answers 24/7 from Deer Park.
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 an oil boiler stop running?
The usual causes are an empty or nearly empty tank, a primary control that locked out after the burner failed to light, a clogged oil filter or nozzle, a dirty or failed cad cell flame sensor, a failed solenoid valve or burner motor, or a tripped switch or breaker.
- Fuel: tank gauge low or sludge pulled into the line after a delivery.
- Lockout: the primary control stopped the burner after a failed light-off.
- Cad cell: the light sensor that confirms the flame; dirty or failed, it shuts the burner down.
- Filter, strainer and nozzle: clogged parts starve the flame.
- Solenoid valve and motor: the valve that feeds oil to the nozzle and the motor that drives the pump and fan.
What can you safely check yourself?
Check the tank gauge, the thermostat, the red-plated service switch and the breaker. Look at the boiler pressure gauge. Then press the burner's reset button once. If the burner lights and runs, watch it for a few minutes. If it locks out again, stop and call; repeated resets pump oil into the chamber.
Our guide to the oil burner reset button explains why one press is the limit. If the tank ran dry, the line usually needs bleeding after the delivery before the burner will run. After a power outage, see a boiler that won't restart.
When should you stop and call right away?
Call right away if the burner locks out again after one reset, you smell oil smoke or see soot, the boiler made a boom or puff-back, water is leaking or the relief valve is discharging, or the house is getting cold in freezing weather. If a CO alarm sounds, get everyone outside first.
- CO alarm or smoke smell: everyone out, then call 911 from outside. See gas smell or CO alarm.
- Puff-back or soot: turn the service switch off and leave it off.
- Leaks: see boiler leaking water.
What does K2 do on an oil boiler no-heat call?
We make the system safe, then test the burner: fuel supply, filter and strainer, nozzle, electrodes, cad cell, primary control, solenoid valve and motor. You get the cause and the price before the repair, and we run the boiler through full cycles before we leave.
On a Bay Shore oil burner in November 2025, we replaced the cad cell and the solenoid valve along with a full tune-up and a new nozzle. A yearly tune-up replaces the nozzle and filter and catches failing parts early; see our Huntington Station oil boiler tune-up and boiler repair.
Recent no-heat calls we fixed
Oil boiler tune-up before the heating season
Huntington Station · Heating Tune-Up · October 2026
A heating-season tune-up on an oil boiler: new oil filter, a full clean, and the system water drained and refilled.
Oil boiler tune-up with two air bleeders replaced
Stony Brook · Heating Tune-Up · October 2026
A fall tune-up on an oil boiler: burner cleaned, oil filter serviced, two failed air bleeders replaced and the system refilled with fresh water.
Questions people ask
My oil tank ran empty. Will the boiler restart after a delivery?
Often not on its own. Running dry draws air and sludge into the line and filter, so the burner may need its line bled and the filter changed before it will run. Press reset once after the delivery; if it does not start, call.
What is a cad cell?
It is a small light sensor in an oil burner that confirms there is a flame. If it is dirty or failed, the primary control thinks the flame went out and locks the burner. Cleaning or replacing it is a common no-heat repair.
How often should an oil boiler be serviced?
Once a year, before the heating season. Oil burners need a new nozzle and filter and a cleaning more than gas equipment does. Skipping it is a common reason for midwinter lockouts.
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