Question 1

What should I do if my boiler stops working?

Accepted Answer

First check your thermostat settings and timer, then check the boiler pressure (should be 1–1.5 bar), try pressing the reset button, and make sure your gas supply is on. If none of these resolve the issue, call a Gas Safe engineer. Never attempt to repair a gas appliance yourself.

Question 2

How do I repressurise my boiler?

Accepted Answer

Locate the filling loop (usually a silver flexible hose under the boiler), open both valves slowly until the pressure gauge reads 1–1.5 bar, then close both valves. If your boiler keeps losing pressure, there may be a leak in the system and you should call a Gas Safe engineer.

Question 3

How do I bleed a radiator?

Accepted Answer

Turn off the heating and let it cool. Use a radiator key to turn the bleed valve (at the top corner of the radiator) anticlockwise until you hear air hissing. Hold a cloth underneath. When water starts to drip, close the valve. Check the boiler pressure afterwards — it may need topping up.

Question 4

Why is my boiler making a banging noise?

Accepted Answer

Banging noises ('kettling') are usually caused by limescale build-up on the heat exchanger or air in the system. It can also be caused by sludge in the pipes or a failing pump. A power flush or descaler treatment can help — call us for advice.

Question 5

When should I replace my boiler rather than repair it?

Accepted Answer

If your boiler is over 15 years old and needs a major repair (over £500), replacement is usually better value. For newer boilers or minor faults, repair is almost always the right choice. Our engineers will always give you an honest recommendation.

Boiler Help & Advice | Common Problems Explained