A broken boiler can be stressful, especially during cold weather in Glasgow

When heating or hot water suddenly stops working, it is often due to a handful of common faults that can sometimes be checked and resolved quickly before calling an engineer.

This guide outlines 7 of the most common reasons a boiler stops working, along with simple steps to help identify the issue safely.

1. No Power to the Boiler

One of the most common issues is a loss of power. This could be caused by a tripped fuse, a switched-off isolator, or a blown boiler fuse.

Fix: Check the fuse box, ensure the boiler switch is on, and confirm the power supply is active.

2. Low Boiler Pressure

Boilers need sufficient water pressure to operate correctly. If the pressure drops too low, the system may shut down.

Fix: Check the pressure gauge. If it is below the recommended level (usually around 1.0–1.5 bar), repressurise using the filling loop if you are confident doing so safely.

3. Thermostat Issues

Sometimes the boiler is working fine, but the thermostat is not triggering it to turn on.

Fix: Ensure the thermostat is set to a temperature higher than the current room temperature and has working batteries if applicable.

4. Frozen Condensate Pipe

During cold weather, the external condensate pipe can freeze, causing a blockage that shuts the boiler down.

Fix: Thaw the pipe gently using warm (not boiling) water or a warm cloth. Restart the boiler afterwards.

5. Air in the Radiators

Trapped air can prevent hot water from circulating properly through the system.

Fix: Bleed the radiators using a radiator key until water flows steadily.

6. Faulty Diverter Valve

The diverter valve controls whether hot water goes to taps or radiators. If it fails, you may lose heating or hot water.

Fix: This is not a DIY repair. An engineer will usually need to replace or repair the valve.

7. Boiler Lockout or Internal Fault

Modern boilers shut down automatically when they detect a fault to prevent damage.

Fix: Try resetting the boiler once. If it continues to lock out, it likely requires professional diagnosis.

When to Call a Heating Engineer in Glasgow

If basic checks do not restore your heating or hot water, it is best to contact a qualified engineer. Persistent faults, leaks, pressure loss, or repeated lockouts usually indicate a deeper issue.

Why Contact The Boiler Exchange When Your Boiler Is Not Working

The Boiler Exchange provides fast boiler repair and replacement services across Glasgow, helping homeowners restore heating quickly and safely.

Whether the issue is a breakdown, an ageing system, or a complete failure, experienced engineers can diagnose the fault and recommend the most cost-effective solution, including same-day replacement options where required.

FAQs: Boiler Not Working in Glasgow

Why has my boiler suddenly stopped working?

Common causes include low pressure, power issues, thermostat faults, or a frozen condensate pipe.

Can I fix a boiler myself?

Basic checks like pressure, thermostat settings, and frozen pipes can be done safely, but internal faults require a qualified engineer.

What does boiler lockout mean?

It means the boiler has detected a fault and shut itself down to prevent damage.

Why is my boiler on but there is no heat?

This could be due to a faulty diverter valve, air in the system, or thermostat issues.

How do I know if my boiler pressure is too low?

Check the pressure gauge. Anything below 1.0 bar usually indicates low pressure.

Why does my boiler keep losing pressure?

This is often caused by a leak in the system or a faulty expansion vessel.

Should I repair or replace my boiler?

If the boiler is over 10–15 years old or requiring frequent repairs, replacement is often more cost-effective.