Common Issues with Oil-Fired Boilers: Troubleshooting Tips and Tricks.

Common issues with oil-fired boilers include clogging of fuel filters, faulty ignition systems, and leaking tanks. Oil-fired boilers are popular in many homes but they require regular maintenance to ensure efficient operation and safety.

In this article, we will discuss some of the most common problems experienced by homeowners with oil-fired boilers and provide solutions to solve them. Whether you’re a homeowner looking to maintain your boiler or a technician looking for valuable information, this guide will equip you with the knowledge to keep your oil-fired boiler running smoothly.

Read on for expert advice on troubleshooting oil-fired boilers.

Common Issues with Oil-Fired Boilers: Troubleshooting Tips and Tricks.


Understanding The Basics Of Oil-Fired Boilers

Overview Of How Oil-Fired Boilers Work

Oil-fired boilers are an essential source of heating for many homes and businesses. These boilers work by burning oil to heat water, which then circulates throughout the property to provide warmth in each room. To understand how these boilers function, here are the key points to take note of:

  • Fuel oil is burned inside the combustion chamber of the boiler.
  • The heat produced by the burning oil is transferred to the water, which begins to boil.
  • The steam or hot water produced by the boiling water is then circulated throughout the building using radiators or underfloor piping.
  • The heat generated from burning oil is regulated to ensure it doesn’t get too high or too low.
  • The combustion gasses generated during the burning process are expelled through the boiler’s chimney.

Different Types And Designs Of Boilers

There are several types of oil-fired boilers available, and each has unique features and designs. Some of these boiler types and designs are listed below:

  • Conventional boilers: Uses a storage tank to hold hot water for use.
  • Combination boilers: Produces hot water on demand without the need for a storage tank.
  • System boilers: Supplies hot water to the storage tank, which can then be used when needed.
  • Condensing boilers: Recycles the heat produced by the boiler to heat the water, making them more energy-efficient.

Importance Of Proper Installation And Maintenance

Proper installation and maintenance of oil-fired boilers are essential to keep them functioning efficiently and ensure safety. Here are some of the reasons why it’s important to maintain and install these boilers correctly:

  • Safety: Faulty boilers can be dangerous and lead to deadly carbon monoxide poisoning or explosions.
  • Efficiency: Regular maintenance increases the efficiency of the boiler, saves on energy bills and prolongs its lifespan.
  • Compliance: Proper installation and maintenance ensures the boiler complies with regulations and safety standards.
  • Fewer repairs: Regular maintenance ensures that small issues are identified and repaired before they become significant problems that require more costly repairs.
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It’s important to engage a professional with the technical expertise to install and service oil-fired boilers. Regular servicing and maintenance will ensure optimal performance and avoid potential hazards.

Troubleshooting Common Issues With Oil-Fired Boilers

Oil-fired boilers are a reliable and efficient way to heat your home. Nonetheless, like most appliances, they may encounter problems that prevent them from performing to their full potential. Knowing how to troubleshoot common issues with oil-fired boilers can keep your home warm and save you money.

Here are some tips and tricks to help you troubleshoot.

Cold Radiators Or Uneven Heating

If your radiators are not heating correctly or are only partially heating, that’s a clear indication of an uneven heating system. Here are some things you can do to fix it:

  • Check for air in the system. If you can hear gurgling noises and the radiators are not heating as they should, bleeding the radiators can help.
  • Make sure that the pump is working correctly. The pump circulates water through the system and helps heat your home. A faulty pump will reduce water flow through the system and cause cold radiators.
  • Check if the differential pressure valve (dpv) is not working correctly. If the dpv is faulty, then the heating system will not distribute heat evenly.
  • If all the above check out, it could indicate a blocked pipe, leading to a poor flow rate in specific radiators.

No Heat Or Hot Water

If you turn on the heating or hot water, and it doesn’t work, here are some things you can do to troubleshoot:

  • Check if the oil tank is empty or very low. Refill the oil tank if necessary.
  • Make sure the burner restart button is pressed. If it pops up, it might indicate that there is no flame in the boiler.
  • Check if the pilot light is lit. If it isn’t, then you’ll need to relight it.
  • Check for a broken fuse, which may have cut off power supply to the boiler.

Leaking Or Low-Pressure Boiler

Oil-fired boilers tend to lose pressure over time naturally. Low pressure is normal, as long as it stays within 1 bar when the heating is on and between 1. 5 and 2 bars when the heating is off. Here are some things you can do to troubleshoot leaking or low-pressure boiler:

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  • Check for leaks. A sealant may fix the problem, but if not, you’ll need a professional to diagnose and repair the issue.
  • Make sure the pressure valve is working correctly. A faulty pressure valve can cause a drop in boiler pressure, leading to poor heating and leaking. If the pressure valve is not working correctly, it will need replacing.

By following these troubleshooting tips and tricks, you can identify and overcome common issues with oil-fired boilers, ensuring that your home is warm, comfortable, and energy-efficient.

Tips And Tricks For Maintaining Oil-Fired Boilers

Regular Cleaning And Inspection

Regular cleaning and inspection are essential for maintaining the efficiency and longevity of oil-fired boilers. Here are some key points about this task:

  • Aim to clean the boiler at least once a year, ideally before winter sets in. Make sure to turn off the power supply and allow the system to cool before starting the cleaning process.
  • The main areas to focus on during the cleaning process are the heat exchanger, combustion chamber, and flue. Use a soft-bristled brush to remove any debris and dirt that has accumulated.
  • Check the oil filter regularly, and clean or replace it as needed. A clogged filter can significantly reduce the boiler’s efficiency and put a strain on other parts of the system.

Importance Of Keeping The Oil Tank Filled

One of the most significant issues with oil-fired boilers is running out of fuel, which can cause significant damage to the system. Here’s what to keep in mind:

  • Check the oil tank gauge regularly and schedule a refill when the level drops to 25% or less. Don’t wait until you’re almost out of fuel before refilling, as this can cause problems with sediment buildup.
  • If possible, try to keep the oil tank at least half-full during the summer months to minimize the risk of condensation forming inside the tank. This moisture can lead to corrosion and other issues.

Best Practices For Scheduling Maintenance And Repairs

To avoid costly emergency repairs, it’s crucial to schedule regular maintenance and address any issues promptly. Here are some key points to keep in mind:

  • Find a trusted professional contractor who specializes in oil-fired boilers. They should have the experience and expertise to perform routine maintenance and identify potential problems.
  • Schedule annual maintenance at least a month before the start of the heating season. This gives the contractor plenty of time to address any issues before you need to rely on the system.
  • If you notice any unusual noises, changes in heating performance, or other issues, call the contractor immediately. Ignoring these signs can lead to more extensive and costly repairs.
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Common Issues That Could Lead To Increased Maintenance Costs

While regular maintenance can help avoid many issues with oil-fired boilers, there are still some common problems that you should be aware of. Here are some key points to keep in mind:

  • Sediment buildup in the tank can clog filters and reduce the efficiency of the system. Regular cleaning and refilling can help prevent this issue.
  • A faulty thermostat can cause the system to cycle on and off too frequently, which puts a strain on the boiler and increases your energy bills.
  • Ignoring unusual noises, leaks, or other visible signs of wear and tear can lead to more costly repairs in the long run.

Importance Of Regular Maintenance And Potential Cost-Savings

Regular maintenance and prompt repairs can help you avoid costly emergency repairs and extend the life of your oil-fired boiler. Here are some key points to keep in mind:

  • A well-maintained system is more efficient and will save you money on energy bills over time.
  • Regular cleaning and inspections can catch potential issues before they become major problems, saving you money on repairs down the line.
  • Addressing issues promptly can also help extend the life of your system and reduce the need for costly replacements.


All in all, oil-fired boilers have a vast range of advantages over other types of boilers; however, they are subject to their own unique issues. The common issues with oil-fired boilers discussed in this post can be prevented with regular maintenance and inspection.

Maintaining the cleanliness of the system’s components such as the burner and filters is one significant preventive measure. Also, checking for any leaks around the oil tank and the boiler itself can help in averting any potential fire hazard. In addition, regular professional inspections can ensure efficient and safe operations of the heating system.

As an oil-fired boiler owner, it is vital to be meticulous in maintaining it in top condition to maximize its lifespan and minimize repairs and replacements.


I am a mechanical engineer and love doing research on different home and outdoor heating options. When I am not working, I love spending time with my family and friends. I also enjoy blogging about my findings and helping others to find the best heating options for their needs.