The Job of the Oil Burner Reset Button
The reset button sits on the primary control, the small box mounted on the burner or on the smoke pipe above it. The control's job is to prove the flame. When the burner starts, a sensor called the cad cell looks for light from the fire. If it sees flame within a set number of seconds, the burner keeps running.
If it does not, the control cuts the oil and locks out, and the red button pops up or lights.
Pressing the button clears the lockout and lets the burner try again. That is all it does. It does not fix whatever stopped the flame from proving the first time, which is why the rule about pressing it once matters so much.
Press the Reset Button Once and Only Once
Every time the burner tries to start, the fuel pump pushes oil through the nozzle whether or not it lights. If the oil did not ignite on the first try, it is sitting in the combustion chamber as a wet puddle. A second press adds a second puddle. By the third or fourth press there is enough oil in the chamber that when it finally does light, it lights all at once.
That is a puffback: a small explosion that blows soot through the house, can crack the combustion chamber and sometimes damages the burner itself. A puffback turns a $189 service call into a cleanup job and often a chamber repair. One press is free. The fourth press can be the most expensive thing you do all winter.
If one press gets the burner running and it stays running through a full cycle, you are fine for now. Make a note of it and book an oil burner tune-up, because a burner that needed a reset is telling you a part is on its way out.
Reasons the Burner Locked Out in the First Place
A lockout means the control did not see a flame in time. On Long Island oil burners the cause is almost always one of these:
- A sooted cad cell. The eye that looks for the flame is coated in soot and cannot see it, so the control shuts down a burner that is actually lit. Common on burners that skipped last year's tune-up.
- Weak ignition. Cracked electrode porcelain or a tired ignition transformer gives a spark too weak to light the spray, especially on cold mornings when the oil is thick.
- No oil at the nozzle. A clogged nozzle, a clogged oil filter or pump strainer, or air in the line after the tank ran low. The burner motor runs but nothing sprays.
- An empty tank, or one that reads a quarter full because the gauge is stuck. Tap the gauge and watch whether the float drops.
- Gelled oil in an outdoor tank or an exposed line on a night below freezing. The heating oil gelling guide explains how to tell gelling from an empty tank.
- A failing primary control that locks out even when the flame is fine.
None of those are fixed by pressing the button again. All of them are fixed on a single service call, because nozzles, filters, strainers, cad cells, electrodes and igniters ride on every Domino truck. The oil burner parts page describes each one.
Checks to Make Before You Press Reset
Two minutes on these checks saves a lot of homeowners a service call, and they come before the reset, not after it:
- The thermostat is set to Heat and a few degrees above the room temperature, and its batteries are not dead.
- The red emergency switch, the plate switch at the top of the basement stairs or beside the unit, is On. Guests and children flip it by mistake.
- The breaker for the heating system has not tripped.
- The oil tank gauge shows oil, and the gauge moves when you tap it.
If all four are fine, press the reset button once and listen. A burner that fires and runs is a burner that needs a tune-up soon. A burner that runs for a few seconds and shuts down, or that never fires at all, is a repair.
The Service Call for a Locked-Out Burner
The technician starts where the control stopped: is there oil at the nozzle, is there a spark, and can the cad cell see the flame? A pressure gauge on the pump, a look at the electrodes and a test of the control's timing answer those in a few minutes. The worn part is replaced from the truck, the oil line is bled if the tank ran low, and the burner is fired and watched through a full cycle before the technician leaves.
When the lockouts have been going on for a while, the combustion chamber is checked for the oil and damage that repeated resets leave behind. The service call is $189 plus parts, with every part priced before it goes in. Calls outside regular hours carry an additional charge that is quoted before the truck is sent.
When a Lockout Is an Emergency
The lockout itself is safe. The control has done its job and shut off the oil. The emergency is the house: on a Long Island night below freezing, baseboard pipes on outside walls can freeze within hours, and a frozen pipe costs far more than a burner repair.
Call for emergency oil burner service the same day if the burner will not stay running and the temperature is below freezing, if you smell oil or see smoke after a reset, or if the burner rumbles or bangs when it starts. No-heat calls go ahead of other work when it is freezing outside, and the phone is answered 24 hours a day.
Related Reading
- Common oil burner problems and what to check first
- What to check before calling a technician
- Bleeding your oil burner pump after running out of oil
Burner Locked Out Again? Call Domino
Leave the button alone after one press and call (631) 867-2231. A NORA-certified technician comes out the same day in most cases anywhere in Suffolk County, Nassau County or Queens, with the parts on the truck and the price quoted before the work starts.