Troubleshooting your Heating Oil Furnace or Boiler

Heating system have a meltdown? Believe it or not, there are a few things a homeowner can do to troubleshoot a heating oil system, if it’s not working.

Let’s say you wake up in January and find it’s not just cold outside, it’s cold inside as well. Whoops. Before you totally freak out or blame your housemates for leaving their windows open, give your furnace or boiler a once over. You never know—you just might be able to figure it out.

There are four fairly common reasons why your heating system won’t work. If you want to be a hero, take the time to rule out each cause.

Cause #1: Your thermostat got turned down.

Thermostats can mess up the heating system in a couple of ways:

Newer ‘smart’ thermostats require batteries. If your heating system isn’t turning on, make sure your thermostat batteries are still good. This is the equivalent of taking your laptop to the genius bar and having them ask you if you tried plugging it in.

Make sure the thermostat is set to ‘heat’. Blame it on poltergeists or angry house elves, it can happen that the thermostat gets turned down. If you – or someone else – has set the thermostat to come on once the room temperature falls to 55°(F), it’ll do just that. If the room temp is 60°(F) and you’re already cold, grab a sweater or reset the thermostat, ‘cuz it won’t come on until it’s 55° in the room—no matter what insults you hurl at it.

Cause #2: Your electricity is off.

Even though your heating system runs on heating oil, it still needs an electric spark to ignite the flame in the combustion chamber that starts the heating process and gets things rolling.

It also needs electricity to power the bower/fan or pump that’s used to move the hot air or hot water from the furnace or boiler to the other parts of your house.

So, if there’s a blackout in your neighborhood or a circuit is blown, your heating oil furnace or boiler won’t work. Step #2 of the troubleshooting list is to make sure neither of those are the culprit before you continue to step #3.

Cause #3: The emergency shut off switch has been flipped.

It happens. By law, every residence is required to have an Emergency Shut Off Switch that allows first responders, oil burner service technicians, and others to be able to shut the furnace off quickly.

You’ll most likely find the switch on your furnace or boiler as well as one located somewhere else like on the flight of stairs coming up from the basement.

An emergency shut off switch looks like a regular light switch but with a couple of differences. Where light switches are often white or beige, the emergency shut off switch usually has a bright red faceplate. The on and off positions on the emergency shut off switch are also the reverse of a light switch, e.g. when it is flipped up, the system is off and when it is flipped down, the system is on.

Installing these switches in odd locations is supposed to make it more difficult for the switches to be turned off accidently. But it can happen. All it takes is for someone to think they’re turning on some lights or for your energetic 10-year-old to “accidently” nail it with a soccer ball, and your furnace won’t start until the switch is flipped on again.

So, your third step in troubleshooting is to check your emergency shut off switch.

Cause #4: You’ve run out of heating oil.

This one gives us the shivers—literally.

If you’ve got power, and you’re sure that the thermostat is set correctly and the system is on, the next step is to check your oil gauge and make sure your tank is filled.

The most common heating oil tank measures 275 gallons (although it only safely holds around 240 gallons). On the top of the tank, there’s usually a gauge (looks like a clear tube with lines on it) to indicate how much fuel is inside the tank.

A tank that shows ½ full will have approximately 120 gallons left inside. ¼ tank is about 60 gallons. If the indicator is below 1⁄8 or isn’t visible at all, the tank may be out of oil and needs to be refilled.  We recommend that customers order at ¼ of a tank…because it rhymes, “order at a quarter.

If you are out of oil, run don’t walk to (just enter your zip in our price check box on this page) or go to the Heatable app and place an order. Like, go now.

If your heating oil system still doesn’t start

If you go through each step of the troubleshooting list and find that even though everything is set correctly, your system still isn’t working, then it’s time to call an HVAC company for help. While here at Heatable we don’t service equipment, we recommend using Google to find someone who does. Or drop us a line, and we may be able to suggest one we know that services your hometown.

Troubleshooting your oil furnace or boiler in 4 easy steps

Here are the Cliff notes for you, if your furnace or boiler is having a moment:

Step #1: Check the thermostat and make sure it is set correctly.

Step #2: Check that there is no power outage in your neighborhood or that the circuit that controls your furnace or boiler wasn’t blown.

Step #3: Check the emergency shut off switch and make sure it is turned to the on position. If you have more than one switch, then be sure to check both.

Step #4: Check the oil gauge on your oil tank to see if you’ve run out of heating oil.

Still not warming up? Call a pro.

With these 4 steps, you’ll be able to troubleshoot your heating system on your own…and avoid a potentially embarrassing encounter with a service provider.

Keep this up, and we’ll name you an honorary Heatable employee.