Boiler Not Heating? Common Causes and Quick Fixes

When your boiler, a central heating system that circulates hot water or steam through radiators to warm your home. Also known as a heat source, it's the heart of your home's comfort stops working, it’s not just inconvenient—it’s cold, stressful, and expensive if you wait too long. A boiler not heating doesn’t always mean a full replacement. More often, it’s a simple issue like low pressure, a faulty thermostat, or a blocked pump that’s easy to fix if you know where to look.

Related problems like no hot water, a situation where your taps run cold even though the boiler is running often go hand-in-hand with heating failure. These aren’t random glitches—they’re symptoms. For example, if your boiler fires up but the radiators stay cold, the circulation pump might be stuck. If the pressure gauge reads below 1 bar, you likely need to repressurize the system. And if the thermostat isn’t responding, it could be a wiring fault or a dead battery. Many of these issues are covered in detail in the posts below, from simple DIY checks to signs that point to a professional repair.

Don’t confuse a boiler not heating with a broken radiator. One radiator cold? That’s probably air trapped in the system. But if every radiator is cold and your boiler is running, the problem is deeper—likely in the boiler itself. Common culprits include a failed ignition system, a blocked flue, or a broken heat exchanger. These aren’t always obvious, but they leave clues: strange noises, error codes on the display, or a pilot light that won’t stay lit. The posts here give you real-world examples from people who’ve been there—what they tried, what worked, and when they called in help.

You don’t need to be a plumber to start troubleshooting. Check the pressure. Listen for the pump. Test the thermostat. These steps take five minutes and can save you a service call. But if you smell gas, see water leaking from the boiler, or hear banging sounds that won’t stop—stop. Don’t risk it. Some fixes are safe to try yourself. Others need a Gas Safe registered engineer. The guides below walk you through both scenarios, so you know exactly when to act and when to wait.

What you’ll find here aren’t generic tips. These are real fixes from real homes in Northampton and beyond. From resetting a boiler after a power cut to diagnosing a faulty diverter valve, the articles give you the exact steps, tools, and red flags to watch for. Whether you’re dealing with a gas boiler, combi boiler, or older system, there’s a guide here that matches your situation. No fluff. No theory. Just what to check, what to fix, and when to call for help.