Boiler Not Heating? Common Causes and Real Fixes

When your boiler, a central heating system that uses gas to warm water for radiators and taps. Also known as a central heating unit, it’s the heart of your home’s warmth—especially in winter. If it stops heating, your whole house feels the chill fast. This isn’t just an inconvenience; it’s a safety issue too. A boiler that won’t heat could mean a faulty thermostat, low pressure, a broken pump, or worse—a gas leak. Don’t ignore it.

Most people jump to replacing the boiler, but boiler repair, the process of diagnosing and fixing faults in a gas-powered heating system often fixes the problem for a fraction of the cost. Many issues start small: a blocked filter, a tripped reset button, or air trapped in the system. These are easy to miss if you don’t know what to look for. And while some think any plumber, a tradesperson who installs and fixes water and gas pipes can handle it, only a gas engineer is legally allowed to work on gas appliances in the UK. Mistakes here aren’t just costly—they’re dangerous.

What you’ll find in the posts below are real, practical fixes from people who’ve been there. From checking the pressure gauge to testing the thermostat, from understanding why a radiator stays cold while others heat up, to knowing when a 15-year-old boiler is beyond saving—this isn’t theory. These are the steps homeowners took before calling in a pro, or after they realized they couldn’t fix it themselves. You’ll see what parts commonly fail, how much repairs actually cost in 2025, and what signs mean it’s time to walk away from repair and go for replacement. No fluff. No guesswork. Just what works.