When to Reset an Oil Furnace or Boiler, and When to Stop

Your oil furnace or oil boiler has shut down and the house is getting cold. There is a small red reset button on the burner, and pressing it is tempting. Sometimes it does restart the system. But that button is part of a safety control, not a quick fix.

Before you touch the reset button, check the thermostat, the breaker and the oil tank gauge, and make sure there is no oil smell, smoke or soot. If everything checks out, press the reset button once and let go. If the burner does not start and keep running, or it shuts down again, stop and call for service. Never hold the button down longer than a couple of seconds, and never press it a second time.

What the Reset Button Does

Oil furnaces and oil boilers use a burner control (often called the primary control) to watch for a flame. When the burner tries to start and does not light properly, the control shuts it down and locks it out.

On most systems, the reset is a red button on the control box mounted on the burner, and it may light up when the burner is locked out. On some older systems, the control is mounted on the metal exhaust pipe instead, and the reset is a red button on the front of that control. Controls differ by make and age, but the safe rule is the same for all of them: one press at most, then call if it does not stay running.

Each time the burner tries to start and fails, it can spray oil into the combustion chamber that does not burn.

Many newer burner controls limit how many times the reset can be pressed. The rule is simple: one press at most.

Stop Signs: Do Not Press Reset If You Notice Any of These

Check for these first. If you see any of them, skip the reset and call for service:

• An oil smell in the house.
• Oil on the floor around the furnace, boiler or tank.
• Smoke, or soot around the burner, the unit or the registers.
• A recent puff, bang or boom when the burner tried to start.
• A reset button that has already been pressed since the last time the heat worked.

If a carbon monoxide alarm sounds, or anyone has a headache, dizziness or nausea, get everyone outside into fresh air and call 911. Do not go back in to check the equipment.

Check These Before You Press Reset

Many no-heat calls are not burner problems at all. Look at these first:

1. The thermostat. Make sure it is set to heat and set a few degrees above room temperature. If it runs on batteries, check that the screen is on.
2. The breaker. Check the breaker for the heating system in your electrical panel. If the breaker for the heating system has tripped, do not keep resetting it; call for service.
3. The oil tank gauge. Look at the gauge on top of the tank. If it reads empty or close to empty, do not press reset. Call your oil supplier for a delivery, then call for service. A burner that has run out of oil usually needs a technician to restart it safely, because air gets into the fuel line.

How to Press the Reset Button Once

If the stop signs are clear, the thermostat is calling for heat, the power is on and the tank has oil:

1. Press the red reset button once and let go. A quick press works on most controls; some need about 2 seconds. Do not hold it longer than that.
2. Stay nearby and listen. The burner should start within about a minute and keep running. Some controls wait several seconds before trying, so give it time rather than pressing again.
3. If it lights and keeps running, watch for heat over the next hour, and schedule a service visit anyway, because a lockout usually has a cause.

Many modern burner controls, including common Beckett and Honeywell models, go into a restricted or “hard” lockout after several failed starts in a row. Their manufacturers designed this to stop the reset button from being pressed over and over. Clearing it takes holding the button down, which is a step for a technician who has found the cause, not a homeowner fix. If a single press does nothing, that is your answer: call for service.

When to Stop and Call for Service

Call a technician and do not press the button again if:

• The burner does not start after one press.
• It starts but shuts down again, now or later the same day.
• You hear a puff, bang or rumble when it starts.
• You smell oil or exhaust, or see smoke or soot.
• The tank was empty or you are not sure.

Call a qualified technician if the heat does not come back on.

Common causes of repeated lockouts include running low on oil, a clogged oil filter or nozzle, air in the fuel line, a dirty flame sensor (often called a cad cell), ignition problems, or a venting or chimney problem. These need a trained technician with the right test equipment. Do not try to bleed the fuel pump, prime the line, clean the flame sensor or bypass any safety control yourself.

Keep Oil Heat Ready for Winter

An oil furnace or boiler that sat idle all summer is more likely to lock out on its first cold night. A heating tune-up by a qualified technician before winter is a good time to find these problems before the cold sets in.

Service First HVAC services and repairs oil furnaces and oil boilers across Bucks County, and 24/7 emergency service is available when the heat goes out. Call (215) 876-0486 or learn more about our furnace repair and boiler services.

Frequently Asked Questions