Boiler Broken? What to Do, How Much It Costs, and When to Repair or Replace

When your boiler, a key heating system that circulates hot water or steam through your home. Also known as central heating unit, it’s one of the most critical appliances in your house—especially in winter. Suddenly stops working, it’s not just inconvenient—it’s urgent. A boiler broken situation means no hot water, no radiators, and possibly frozen pipes if it’s cold outside. Most people assume a broken boiler means a full replacement, but that’s not always true. Many times, a simple fix—like resetting the pressure, clearing a blocked pipe, or replacing a faulty thermostat—gets you back up and running for under £200.

What causes a boiler to break? It’s usually one of three things: age, lack of maintenance, or a single broken part. If your boiler is over 10 years old, it’s more likely to fail suddenly. But even newer ones can go down if they’ve never been serviced. Common issues include low water pressure, thermostat failure, frozen condensate pipes, or a broken pump. These aren’t always expensive to fix. For example, replacing a pressure sensor costs about £80–£150, while a full pump replacement might run £250–£400. But if your boiler is leaking from the heat exchanger or making loud banging noises, that’s a sign of deeper damage. At that point, repair costs can quickly climb past half the price of a new unit.

That’s where the decision gets tricky. You’re not just paying for parts—you’re paying for safety, efficiency, and peace of mind. A new combi boiler, a type of boiler that heats water on demand and doesn’t need a storage tank. Also known as combination boiler, it’s the most popular choice in UK homes today. might cost £2,000–£3,500 installed, but it’ll cut your energy bills by 20–30% and last 15+ years. A 15-year-old boiler? It’s already running at 70% efficiency at best. Every £100 you spend on repairs now might just be buying you another year before the next breakdown. And if your boiler uses an outdated gas valve or lacks modern safety sensors, it could even be a risk.

What to do right now if your boiler is broken

First, don’t panic. Turn off the power and gas supply if you smell gas or see water pooling. Then check the pressure gauge—most boilers need 1–1.5 bar. If it’s below 0.5, you might just need to repressurize it using the filling loop. Next, look for error codes on the display. Most modern boilers show codes like F28 (ignition failure) or E133 (flue problem), which tell a gas engineer exactly what’s wrong. Don’t try to fix it yourself if it involves gas lines, electrical components, or internal parts. That’s not DIY territory—it’s a job for a Gas Safe registered engineer, a certified professional legally allowed to work on gas appliances in the UK. Also known as certified gas technician. A quick diagnostic call usually costs £60–£80, but that’s often deducted from the repair bill if you go ahead.

What you’ll find below are real, practical guides from homeowners who’ve been there. You’ll see how much others paid to fix their boiler, what parts actually failed, and whether they wished they’d replaced it instead. Some saved money with a simple fix. Others avoided disaster by replacing before it broke. No fluff. No upsells. Just clear, honest advice from people who’ve dealt with a boiler broken in the middle of winter—and lived to tell the tale.