🔧 Why Is My Boiler Losing Pressure?

A boiler losing pressure is one of the most common issues homeowners face — and luckily, it’s often easy to spot and fix. But if left too long, it can lead to cold radiators, low heating output, or even total boiler shutdown. Here’s everything you need to know:

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💡 What Does Boiler Pressure Mean?

Boiler pressure is the balance of water and air inside your central heating system. It’s measured in bar (you’ll see this on the pressure gauge). The ideal pressure is usually between 1.0 and 1.5 bar when the system is cold.

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🚨 Common Reasons for Pressure Loss

• Leaks in the System
  Look for damp patches under radiators, pipes, or the boiler itself. Even small leaks can slowly reduce pressure over time.

• Bleeding Radiators Recently
  Releasing air also releases pressure. After bleeding, you’ll often need to top up the system.

• Faulty Pressure Relief Valve or Expansion Vessel
  These components can wear out or fail, especially in older boilers.

• Air in the System
  Air locks or trapped air pockets can cause fluctuations in pressure.

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🧰 How to Re-Pressurise Your Boiler (Combi Systems)

📌 Always check your boiler manual first. If unsure, call a professional.

1. Turn off the boiler and let it cool down.

2. Locate the filling loop – usually a silver braided hose under the boiler.

3. Slowly open both valves and watch the pressure gauge.

4. When it reaches 1.3 to 1.5 bar, close both valves tightly.

5. Turn the boiler back on.

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🧑‍🔧 When to Call a Gas Safe Engineer

If you notice:

• Pressure drops daily, even after topping up.

• You can’t find a visible leak.

• You hear unusual noises (banging, gurgling).

• There’s no hot water or heating.

It’s time to let us take a look. Ignoring pressure issues can damage internal boiler parts, costing more in the long run.

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📞 Need Help?

At Blue Flame Plumbing & Heating, we offer fast, expert boiler diagnostics and repairs across Nottingham, Derby, and nearby areas.

✅ Gas Safe Registered
✅ 24/7 Emergency Service
✅ No Hidden Costs

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