Ran out of oil? Do this first
The house is cooling down, the furnace is silent, and the gauge says empty. It happens to careful people every winter — gauges stick, cold snaps burn fuel faster than anyone's mental math. Work through these steps in order, and know where the line is between "safe to try" and "call a technician."
Step 1: Confirm it's really the fuel
- Check the gauge directly, and tap it. Oil gauges can stick. A gentle tap on the gauge can free a hung float. If it's at or near empty, believe it.
- Check the thermostat — set to Heat, set above room temperature, batteries alive if it has them.
- Check the emergency switch (usually a red switch plate, often at the top of the basement stairs or near the furnace). It gets bumped off by accident more often than you'd believe.
- Check the breaker for the furnace circuit.
Step 2: Get fuel coming
Call your fuel company and say plainly that you've run out — every company triages run-outs ahead of routine fills, and many run emergency service after hours. If your regular company can't come today and your tank is your own (the normal case for oil), another company from the directory can deliver to you. While you wait, protect the plumbing: in hard cold, let faucets drip slightly and open cabinet doors under sinks on outside walls.
The reset button rule: once
Oil burners have a reset button on the control (often a red button on a gray box on the burner). When a burner shuts down on safety, pressing reset once after fuel is back in the tank is reasonable. Pressing it again and again is not: each press pumps more oil into the combustion chamber without burning it. That pooled oil can ignite all at once when the burner finally fires — a puffback at best, a furnace-damaging fire at worst — and it can flood the chamber so badly that a technician has to clean it before the burner will run right. One press. If the burner doesn't catch and run steadily, hands off, and call a technician. If you've already pressed it several times, say so honestly when the tech arrives — they'll want to know, and it changes how they start the unit.
Step 3: Understand "the line needs bleeding"
When a tank runs dry, the burner pump pulls air into the fuel line. Even with fresh oil in the tank, that air pocket can keep the burner from firing — the line has to be bled, the way you'd bleed a brake line. On many single-line systems this is a simple job for someone who knows the burner; on two-line systems the system often re-primes itself. We're not going to walk you through bleeding your own line here, on purpose: done wrong, it spills oil, and an oil spill in a basement is an environmental and financial headache far bigger than a service call. If fuel is in the tank, one reset press didn't do it, and the burner keeps locking out — that's the technician's job, and it's a common, quick one.
A stopgap that's actually standard advice
If a delivery is hours away and the house is dropping toward freezing, the long-standing stopgap is a few gallons of diesel fuel or kerosene from a clean, clearly-marked container, poured into the fill pipe — furnaces burn diesel because heating oil and diesel are close cousins. A few gallons buys hours of heat. Keep it to a few gallons, keep it clean (dirt and water are burner poison), and never use gasoline — gasoline in an oil tank is genuinely dangerous. Tell the driver when he arrives that you added it.
Step 4: Don't do it again
After the heat's back: run-outs are rough on burners (sludge from the bottom of an empty tank gets pulled toward the filter) and rough on budgets (emergency fees, service calls). The fixes are boring and they work — check the gauge on a schedule (see Read your tank gauge), call at a quarter tank, or move to automatic delivery and let the company's computer watch it for you.