When a home runs out of heating oil, the burner can’t get any more fuel, so it stops making heat. Its safety control then usually shuts it down. The house starts cooling right away, and if the boiler also heats your water, you lose hot water too. A new delivery doesn’t always fix things. A burner that has run dry often pulls air, and sometimes sludge from the bottom of the tank, into the fuel line. In that case a technician has to get it running again.
The good news is that a run-out is very fixable. It’s also very preventable. This guide explains what happens in your basement when the tank goes dry, what you can safely check, and how to avoid going through it again this winter.
What actually happens when the tank goes dry
An oil burner works by pumping a fine spray of oil into the combustion chamber, where it’s lit. As the tank gets close to empty, a few things happen one after another:
- The burner starts sucking air. The fuel pump pulls from a line near the bottom of the tank. Once the oil level falls below that point, the pump draws air and the flame sputters out.
- The safety control locks out. Your burner has a control that watches for a flame. If the burner tries to fire and the control doesn’t see a flame, it shuts everything down and stops trying. That’s the “reset” state many homeowners discover on a cold morning.
- Sediment gets stirred up. Over the years, a layer of sludge and sometimes water settles at the bottom of most oil tanks. A run-out is exactly when the burner pulls from that bottom layer. The gunk can clog the oil filter, the pump strainer or the nozzle.
- Heat and (often) hot water stop. Many older Bucks County homes, from Bristol twins to Levittown ranches, get domestic hot water from a coil inside the oil boiler. No oil means no hot showers either.
Why your heat might not come back after a delivery
This catches a lot of people off guard. The oil truck comes, the tank is full, and the house is still cold.
The usual reason is air in the fuel line. Oil burners don’t handle air well. Until the line is cleared, or “primed,” the pump can’t deliver a steady flow of oil and the burner won’t light reliably. Fuel-oil technicians call this bleeding the line. It involves the fuel system and the burner, so a trained tech should do it.
The second reason is a clogged filter or nozzle. If the burner pulled sludge on its way to empty, the filter or nozzle may now be partly blocked. The tech may need to replace the filter or nozzle before the burner runs cleanly again.
So if you’ve run out, you’ll usually need two things: an oil delivery, and a service visit to get the burner restarted. One call to C&L covers both. Tell us you’re out of oil and the heat is off, and we’ll set up the delivery and the service visit.
Common signs you’ve run out (or are about to)
- No heat, and the radiators, baseboard or vents are cold
- No hot water, if your boiler makes your hot water
- The burner tried to start, then went quiet and stayed quiet
- The tank gauge reads at or near “E.” (Gauges aren’t perfect, but a reading near empty is a strong clue.)
- In the days before: the burner sounded rough or rumbly, or cycled on and off more than usual
What you can safely check
Before you call, a few quick checks can confirm what’s going on. None of them involve touching the burner itself.
- Look at your tank gauge. Most indoor tanks have a small float gauge on top: a clear dome with a marker. If the marker sits at the bottom, you’re very likely out of oil.
- Check the thermostat. Make sure it’s set to heat and turned up above room temperature, and replace its batteries if it uses them.
- Make sure the burner’s emergency switch is on. Most oil systems have a switch, often with a red plate, at the top of the basement stairs or near the boiler. People sometimes flip it off thinking it’s a light switch. If it’s off, turn it on once.
- Think back to your last delivery. If it’s been a while and the weather has turned cold, a run-out is the likely cause.
What NOT to do
These matter for your safety and for your equipment:
- Don’t press the reset button. Your burner has one, but each press can spray oil into a combustion chamber that isn’t lighting properly. Unburned oil can build up and ignite all at once, which can cause a puffback of soot and smoke through the house, or worse. If the burner has gone into reset, leave the button alone and call a technician.
- Don’t pour fuel into the tank yourself. It’s tempting to use a few gallons of diesel or kerosene from a gas station can. Handling fuel yourself means spill, fire and fume risks, and it can make the restart harder. Let a delivery driver fill the tank.
- Don’t try to bleed the line or open the burner. That work involves pressurized fuel and electrical parts and belongs to a trained tech.
- Never heat the house with an oven, grill, camp stove or generator indoors. These can produce deadly carbon monoxide. If you use an electric space heater while you wait, use a listed model, plug it straight into a wall outlet, and keep it at least three feet from anything that can burn.
If you smell oil or exhaust fumes, see soot, or anyone feels dizzy, sick or headachy, leave the house and call 911 from outside. Don’t go back in to troubleshoot.
Protecting your pipes while you wait
When it’s cold outside, a home without heat can get cold enough to freeze pipes, especially along outside walls, in crawl spaces and in unheated additions. While you wait for oil and service:
- Keep doors closed to save the heat you have
- Open the cabinet doors under sinks on outside walls
- Let a faucet on a vulnerable line drip slightly
- If you leave the house, tell C&L so the delivery and service visit can be coordinated
When you need a professional
Call a professional in any of these cases:
- Your heat doesn’t come back after a delivery
- The burner is in reset (lockout)
- You hear the burner try to start but it won’t stay lit
- You notice odors, smoke or soot, or see oil on the floor near the tank or burner (leave and call. Don’t clean it up or troubleshoot it yourself.)
A tech can get the burner going again and change a clogged filter or nozzle. They can also look for anything the run-out stirred up. If your system is due for its annual tune-up anyway, that’s a good time to schedule it.
How C&L Fuel helps you avoid running out
C&L Fuel Inc. is a local, family-owned heating, fuel and HVAC company serving Bristol, Levittown, Bensalem and other parts of our Bucks County service area. Here’s how we can help:
- Heating oil. If you’d rather keep an eye on the gauge yourself, call us when it’s time to order.
- Automatic delivery. Ask about it. It takes the guesswork out of watching the gauge, and it’s one less thing to remember when the weather turns.
- Oil heating service. Our techs handle repairs and maintenance on oil boilers and furnaces, including the annual tune-up that keeps your filter, nozzle and burner in good shape before winter.
Frequently asked questions
Will my burner restart by itself once oil is delivered?
Sometimes, but often it won’t. If air or sediment got into the line when the tank ran dry, the line needs to be cleared and the burner restarted by a technician. Plan on a service visit.
Can running out of oil damage my system?
It can lead to problems. Pulling from the bottom of the tank can draw sludge into the filter, pump and nozzle, and a cold house risks frozen pipes. Most run-outs are fixed with a restart and sometimes a new filter or nozzle. Call promptly instead of waiting.
How much oil should I order after running out?
It depends on your tank size, how much of the season is left, and how your home uses oil, so ask when you call and we’ll talk it through with you.
How do I know when I’m getting low?
Check your tank gauge regularly once heating season starts, and order when it reaches about a quarter of a tank. Or ask about automatic delivery, which takes the guesswork out.
Should I press the reset button?
No. The reset button restarts a burner that its safety control shut down for a reason, and each press can let unburned oil build up in the burner. If your burner is in reset, leave the button alone and call a technician.
Out of oil, or tired of watching the gauge?
Ask about automatic delivery when you call. It’s one less thing to remember all heating season. Our regular office hours are Monday through Friday, 9 AM to 5 PM. Our phone is answered 24/7. If you’re experiencing a heating problem, call C&L Fuel Inc. at 215-785-6161 to discuss available service options.
