Although it is highly recommended not to burn all of the oil in your tank and run out, many users forget to order oil until their tanks are almost empty. Even if you make timely orders, sometimes you may still run out of heating oil. When that happens, it’s highly likely that your oil lines took some air and sludge from the oil tank’s bottom. That is why you need to prime your oil burner once you fill your tank again.

Book an oil burner service appointment

Here’s how to prime an oil burner/furnace:

  1. Turn off the power supply to the burner. If you can’t find the switch you will need to go to the breaker box and turn off the furnace’s breaker.
  2. Check the burner’s thermostat. Make sure it’s turned on and set to a temperature higher than the actual temperature of your home. This way you will make sure that it will start immediately when you turn it on again.
  3. Find the bleeder valve on the oil pump. This valve looks like a hex nut and is positioned on the right side of your pump or on the front, depending on the burner make and model.
  4. Place a bucket or tray under the bleeder valve to collect the oil which would leak when you loosen the valve. You will also need a 7/16- or 3/8-inch wrench to loosen it.
  5. When you loosen the valve, you will notice the dirty oil and air bursts coming through it. Press the red reset button to restart the burner and let the oil through the lines again.
  6. When you notice steady flow of clean oil you may tighten the valve. The burner can now start working automatically. If it doesn’t, repeat several times before it starts. In some cases it is needed up to six attempts to restart the burner and put the system in operation.

If your filters aren’t clogged your burner is almost certainly safe. Check if you need to replace it as oil from the bottom of fuel tank has high concentration of soot and other impurities.

Here’s a video that shows how to prime your oil burner and bleed the lines properly:

If you’re not on automatic delivery you should also check the oil level gauge frequently. You can also use a long dipstick made especially for fuel oil tanks, temperature strips or other devices for easy checking of how much oil remains in the tank to avoid running out and possible damage to the system.