Oil Furnace Troubleshooting: How to Restart Safely
Restarting an oil furnace after running out of fuel or after a power outage isn’t always as simple as flipping a switch. Most furnaces are designed to not start if air is present in the fuel lines. This prevents damage that can be costly to repair. If you’re having a problem restarting your furnace, air in the lines is the likely culprit. Here’s how to fix the problem and start your furnace safely.
Determine the Cause of the Outage
In order to properly restart an oil furnace, you need to know why it went out in the first place. In the case of a planned outage, whether for the season or for repairs, no additional considerations are required. If you are restarting an oil furnace after running out of fuel, however, make sure your tank is topped up before proceeding.
Bleed the Fuel Lines
To restart an oil furnace after a power outage or other temporary interruption, often all you have to do is press the red reset button, which is typically located on the control panel. If this doesn’t work, or if your furnace has been sitting for an extended period of disuse, the fuel lines should be bled manually. Here’s how:
- Turn off the furnace completely. Check your owner’s manual if you’re not sure how to do this.
- Locate your furnace’s fuel pump. This is typically a small black box or circle with fuel lines running into it.
- Locate the bleeder valve. On the side of the fuel pump, you should see a small fitting not connected to anything else – this is the bleeder valve.
- Place a drip pan underneath the bleeder valve, or run a length of tubing from the valve into a plastic bottle capable of holding at least 1 liter of fuel.
- Turn the furnace back on, and rotate the valve a half-turn to start bleeding. Keep bleeding the line, ensuring the fuel does not overflow, and press the reset button again. This should trigger the furnace to start.
If the furnace doesn’t start, or if no fuel comes out of the bleed valve, it may be necessary to call a professional for help. You can also try bleeding the oil filter – look for a small black canister with a red top. On the top, you’ll find a one-quarter inch bleed valve. Simply unfasten the valve for a few seconds so air can bubble out.
Though air in the fuel lines is the most common problem preventing an oil furnace from restarting normally, other issues can include damage to the fuel lines themselves, or issues with the oil filter. For assistance with these and other concerns, your best bet is to speak with a professional directly. You can also order your heating oil online today!