Common Vaillant Boiler Faults & How to Fix Them – Expert Advice from a Gas Engineer in Glasgow & Surrounding Areas Vaillant boilers are known for their reliability and energy efficiency.

Common Vaillant Boiler Faults & How to Fix Them – Expert Advice from a Gas Engineer in Glasgow & Surrounding Areas

Vaillant boilers are known for their reliability and energy efficiency, making them a popular choice in homes across the UK. However, like any heating system, they can develop faults over time. As a highly experienced Gas Safe engineer serving Glasgow, Clydebank, Bearsden, Milngavie, Scotstoun, Anniesland, Knightswood, Partick, Maryhill, Paisley, Renfrew, and surrounding areas, I’ve diagnosed and repaired countless Vaillant boiler issues. Below, I’ll cover the most common faults, troubleshooting tips, and when to call in a professional.

1. Vaillant Boiler Not Igniting? Here’s What to Check

If your Vaillant boiler fails to ignite, possible causes include:

Gas Supply Issues – Check if other gas appliances in your home are working.

Faulty Ignition Electrode – If the electrode is dirty or damaged, ignition may fail.

Blocked Condensate Pipe – During cold weather, the condensate pipe can freeze, preventing ignition.

Low Gas Pressure – If the gas pressure is too low, the boiler won’t ignite.

✅ Quick Fix: Try resetting the boiler and checking for blockages in the condensate pipe. If the issue persists, a professional should inspect it.

2. Vaillant Boiler Losing Pressure?

If your boiler’s pressure keeps dropping, it could be due to:

Leaks in the System – Check radiators, valves, and pipework for leaks.

Faulty Pressure Relief Valve – A damaged valve can cause pressure loss.

Air in the System – Bleeding radiators may help resolve the issue.

⚠ Expert Tip: If your boiler loses pressure frequently, it could be due to a hidden leak. A professional inspection is advised.

3. Boiler Making Banging or Whistling Noises?

Strange noises from your Vaillant boiler may indicate:

Kettling – A build-up of limescale in the heat exchanger, leading to overheating.

Trapped Air – Gurgling sounds often signal air pockets in the system.

Pump Failure – A faulty pump can cause loud banging or grinding noises.

🔧 Pro Advice: A system flush can help remove sludge and limescale, improving performance and reducing noise.

4. Common Vaillant Boiler Fault Codes & What They Mean

Your boiler may display error codes. Here are some of the most common ones:

F22 – Low water pressure (repressurise the system using the filling loop).

F27 – Faulty flame detection (check ignition electrode and gas supply).

F28 – No ignition (could be due to a blocked condensate pipe or faulty gas valve).

F75 – Pump or pressure sensor fault (likely caused by debris in the system).

📌 Troubleshooting Tip: Reset the boiler and check the pressure gauge. If the fault persists, professional repair is required.

5. Vaillant Boiler Keeps Switching Off?

If your boiler shuts down unexpectedly, it could be due to:

Low Water Pressure – Check if the pressure is below 1 bar.

Blocked Heat Exchanger – Sludge buildup can cause overheating.

Faulty Thermostat – A misreading thermostat can lead to shutdowns.

Pump Failure – Poor circulation can cause the boiler to shut off.

👨‍🔧 Real-World Case: A customer in Renfrew had a Vaillant boiler that kept turning off. After checking the system, I found a blockage in the pump caused by debris buildup. A system flush and pump replacement solved the problem, restoring full functionality.

6. Boiler Producing No Hot Water?

If your heating works but there’s no hot water, the issue may be:

Diverter Valve Failure – The valve may be stuck, preventing hot water from reaching taps.

Faulty Temperature Sensor – If the sensor is misreading, water won’t heat correctly.

Airlocks in Pipes – Trapped air can restrict hot water flow.

🛠 Quick Fix: Check if the boiler is set to the correct mode. If the problem continues, professional diagnosis is needed.

7. When to Call a Professional Gas Engineer in Glasgow & Nearby Areas

Some minor issues can be resolved by homeowners, but others require expert attention. If your Vaillant boiler:

Frequently loses pressure

Displays persistent fault codes

Leaks water or gas

Is over 10 years old and inefficient

…it’s time to book a Gas Safe registered engineer.

🏆 Why Choose Me? I have extensive experience repairing Vaillant boilers across Glasgow, Clydebank, Bearsden, Milngavie, Scotstoun, Anniesland, Knightswood, Partick, Maryhill, Paisley, Renfrew, and surrounding areas. Whether you need repairs, servicing, or a new boiler installation, I provide reliable, expert service at competitive rates.

📞 Call Now: 07969 047 977

📧 Email: duncan-1stclassgas@outlook.com

🌍 Website: www.repairmyboilerglasgow.co.uk