If your Domusa oil boiler won’t start, there may be several reasons behind the issue. It could be a fuel supply problem, a faulty ignition system, or a malfunctioning component like the burner or photocell. In this guide, we’ll explain the most common reasons why your boiler isn’t starting and what you can do to fix it.
1. Fuel Supply: Is There Oil in the Tank?
It may seem obvious, but it’s the first thing to check. If the fuel tank is empty or the fuel shut-off valve is closed, the boiler will not start.
Solution:
- Make sure there is enough fuel in the tank.
- Check that the valve between the tank and the boiler is open.
This is especially important after a recent refill, as the valve may have been left closed by accident.
2. Dirty or Damaged Electrodes
The electrodes are thin metal rods responsible for producing the spark that ignites the fuel. They must be:
- Clean
- In good condition
- Properly spaced and aligned
If they are dirty, broken, or misaligned, the spark may not be strong enough to ignite the fuel.
Solution: Clean them carefully or replace them if they’re worn or damaged.
3. Transformer Problems
The transformer supplies high voltage to the electrodes. If it fails, the electrodes won’t receive the power needed to create a spark.
Solution: If the transformer is not working, it will need to be replaced.
4. Dirty or Defective Photocell
The photocell is a sensor that detects the presence of a flame. If it doesn’t detect a flame, it will stop the boiler for safety.
Over time, the photocell can become dirty or fail, causing:
- The boiler to shut off shortly after starting
- The system to think there’s no flame when there actually is
Solution: Gently clean the photocell with a soft cloth. If the problem persists, replace it.
5. Burner Malfunctions
The burner mixes the fuel and air and ignites them to generate heat. It’s the core of the boiler’s operation. Over time, it may become clogged with combustion residues, or its components may fail.
In addition, the burner may shut down due to:
- Overheating
- Flue gas obstructions
- Excessive pressure
Solution: Clean the burner and remove any carbon build-up. If that doesn’t fix the issue, check for overheating or vent blockages.
6. Control Board or Electrical Issues
Sometimes, the boiler doesn’t start because of issues with the control unit, wiring, or system sensors. Common problems include:
- Faulty thermostats
- Loose electrical connections
- Low water pressure
Solution: Check the electrical components and connections. Replace any defective parts as needed.
Frequently Asked Questions – Domusa Oil Boiler Not Starting
🔧 Why won’t my Domusa oil boiler ignite even though there is fuel?
There could be air in the fuel line, a dirty electrode, or a faulty transformer. Always check that the valve is open and bleed the line after a refill.
🔍 What are the most common parts that fail?
The most frequent culprits are:
- Electrodes (dirty or damaged)
- Photocell (faulty flame detection)
- Burner (clogged or malfunctioning)
- Transformer (low or no voltage)
⚠️ Is it safe to press the reset button repeatedly?
No. If your boiler goes into lockout mode, press the reset button only once or twice. If it locks again, call a professional technician.
🧼 How often should I clean the burner and electrodes?
We recommend a full boiler maintenance at least once a year. This includes cleaning the burner, checking the electrodes, and testing all safety sensors.
🔁 Can a power outage affect startup?
Yes. After a power cut or voltage spike, the boiler may require a reset. Some components, like the transformer or control board, can also be damaged by electrical faults.
Need Spare Parts for Your Domusa Oil Boiler?
If your boiler still doesn’t start after troubleshooting, you may need to replace a faulty part. Whether it’s electrodes, a transformer, a burner, or a photocell, make sure you use original Domusa parts to ensure compatibility and safety.
🛠 Looking for genuine replacement parts?
Find everything you need at Suner, including:
- Ignition electrodes
- Flame detectors (photocells)
- Transformers
- Burners and control units
All our parts are original and guaranteed, suitable for Domusa oil boilers.
Conclusion
A Domusa oil boiler that won’t start is usually dealing with one of a few common issues—fuel supply problems, dirty ignition components, or faulty sensors. Many of these problems can be fixed quickly with basic maintenance. However, if the issue persists, it’s best to contact a technician and consider replacing defective parts.