Financing Options Available*

View Options

Oil Furnace Troubleshooting DIY

Featured image of the blog title "Oil Furnace Troubleshooting DIY" with a background of furnace

Times have certainly changed in the home building industry including how heat and air circulate throughout the living space. It’s hard to imagine living in regions where you can’t fathom spending one excruciating summer without the use of an air conditioner or a blasting winter without central heat.

For many generations, a wood fire was the only way a family had to stay warm.

Those that live in the coldest parts of the world had only the wood they were able to stock to keep them warm. Modern technology came along, and today there are several methods used besides regular fireplaces.

Oil furnaces are a common source of heat in Reno area HVAC units. Some homeowners swearing by its ability to heat their homes at a better price than other options. It is thought to be the most dependable and durable appliance made for heating your home.

Most companies estimate the average years a unit will last is around ten, however, with proper maintenance and upkeep, a homeowner can get at least 15 years service out of a unit. In this article, we will discuss oil furnace troubleshooting chart that you can do yourself in the case of an issue.

Built to last, but……

Even with the oil furnaces incredible track record, there are still opportunities where ailments will pop up and your unit will need a little first-aid. Unfortunately, moments like this usually take place on a cold winters night.

As the homeowner, you may get lucky and only need a few adjustments or minor repairs to get you back up and running. It is still best to consult a professional instead of taking matters into your hands if you see that you are beyond common setbacks.

The last thing you want is to attempt to make repairs yourself and find that you need more than just a simple adjustment in the middle of the night. If your Oil Furnace turns on and off repeatedly, it is a sign that there are problems that will prevent a unit from functioning correctly and the more you know your equipment, the better you will be in determining what’s a simple fix compared to a massive repair job.

Common oil furnace issues and simple fixes


The oil furnace won’t start:

If you have tried to get, your unit to initiate with no success, press down on the reset button which will manually start the unit. On older models, the reset button is located on the primary controls. With the new models, the reset button is typically on the burner motor.

If your unit doesn’t come on for at least 60 seconds after pressing the reset button no more than two times, check your circuit breaker and fuses. Discontinue pressing the reset button as this loads more fuel into the chamber causing an overload of oil when the unit does ignite.

There are instances where the burner assembly motor will burn out. In the event of this happening, the motor will need replacing, which is a minor cost.  The most common reason for this happening is when over-oiling takes place.

There is no fire even when the burner is running:

First, check the opening to the burner nozzle for any debris or water that may be clogging the small hole. If it’s been awhile since you’ve replaced the nozzle, go ahead and make this repair being it’s inexpensive then check to see if this corrected the problem.

Disconnect the supply line from the burner and allow fuel to flow into a clean, clear jar. If you see water mixed with the oil, you need to minimize the amount of contamination that is mixing with fuel by following these steps.

    • When the oil is pumping into the tank, turn the unit off. Allow it remain off for at least one hour giving what trash that could be in the tank time to settle
    • Have your oil company send a delivery person to check for water in the reservoir. If there are signs of excess water, the tank will need draining to check for cracks.
    • Keeping the tank filled will help prevent disturbing the bottom of the fuel tank like what frequent refills often does.

There are other reasons why this would be taking place. However, you need to let a professional examine your system to get a proper diagnosis before determining the outcome.

Very little heat is blowing through the vents:

In this situation, you should check your air filter to see how clogged it is and change it out of you find it has collected too much dirt and dust. Even though you will find that a filter with small amounts of dirt coating works well when one has so much buildup that it no longer can breathe will impede the airflow causing the system to no longer function well.

You should only need to change the filter no more than twice a year. If you find you need to change it more often, determine how close your clothes dryer is to the unit. You would be surprised how much lint and dust is exhausted from a dryer.

If you find that changing the filter doesn’t resolve the issue, check the “supply-air fan” to verify the belt is not broken. If it is broken or damaged, you will need to replace the belt before the furnace runs correctly.

If the belt is not broken and is in good condition, check the supply-air fan to make sure it is working. These motors have a tendency of burning out after several years of use.

Finally, if all the above steps produce no good understanding as to why the heat is not flowing strong, check your ductwork to ensure there are no leaks. If there are leaks in your ductwork, you will see a huge increase in your heating cost.

Smoke and soot are leaking through the vents


If you are experiencing dirty air coming through your vents, there a couple of reasons this could be happening. First, if you feel the excessive heat and see smoke when you open the combustion chamber door, chances are there are blockages preventing the heat and air from escaping the chamber.

Incidences such as this could be from the following:

    • Insufficient draft due to the flue pipe being too long
    • Clogged flue pipe
    • Cracked or clogged heat exchanger

These reasons are why it is important to have regular maintenance performed by a professional. All three circumstances would be easy to diagnose and could be prevented when the service tech performs routine maintenance on your furnace. If there is a cracked heat exchanger, you will more than likely need to replace the entire furnace.


There are small things that can go wrong with your oil furnace just as well as problems that would lead to having to replace the entire unit. Regular maintenance of your system will save you a lot of money, time and headaches.

Get to know and trust a reliable, professional HVAC company that you can grow to trust for your furnace upkeep. The more quality care you show to your household appliances, including your heating furnace, the longer you can put off having to invest in a costly project.

Skip to content