A boiler losing pressure can be frustrating, especially during cold weather when you need consistent heating and hot water. At DAKS Plumbing, we’ve supported homeowners across Swanley, Dartford, Bexley, Orpington, and wider Kent to diagnose and fix this common issue. This guide explains the main causes, how to repressurise safely, and when it’s time to call a professional.

What Causes Boiler Pressure to Drop?

1. Leaks in the System — The most common cause of a boiler losing pressure is a leak in the heating system. Leaks may appear around radiators, pipes, or the boiler itself. Damp patches or unexplained water loss are key warning signs. Our leak detection services in Kent quickly identify hidden issues.
2. Bleeding Radiators — Releasing trapped air improves heating efficiency, but it also lowers system pressure. After bleeding radiators, you’ll usually need to repressurise your boiler.
3. Faulty Pressure Relief Valve — A damaged valve may release excess water, causing repeated pressure drops.
4. Expansion Vessel Problems — A failing expansion vessel can’t regulate pressure properly, leading to fluctuations.

How to Check Boiler Pressure

Most boilers have a front-panel gauge. When the system is cold, the ideal range is 1.0–1.5 bar. Below this, your boiler needs repressurising; above 2.5 bar, call an engineer immediately.

How to Repressurise a Boiler

1. Turn Off the Boiler — Always switch off and let it cool first.
2. Locate the Filling Loop — A flexible silver hose with two valves, usually under the boiler.
3. Open Valves Slowly — Let water enter the system while watching the gauge.
4. Stop at 1.5 Bar — Close both valves tightly once in range.
5. Restart the Boiler — Check if pressure holds steady.

If your boiler keeps losing pressure after repressurising, it’s likely there’s an underlying fault.

When to Call a Professional

Persistent low pressure often points to leaks, faulty parts, or an ageing boiler. At DAKS Plumbing, we provide expert plumbing services and heating repairs across Kent, including Swanley, Dartford, Wilmington, and West Kingsdown. Our Gas Safe engineers ensure your system is safe and reliable.

Preventative Boiler Care

• Check the pressure gauge monthly to spot early issues.
• Book annual servicing to keep your boiler efficient and safe.
• Consider a replacement if your boiler is over 12–15 years old or frequently fails.

Other Home Maintenance Services

Alongside boiler repairs, we provide: bathroom installations, drainage solutions, and timber & damp surveys. Our goal is to keep every part of your home’s plumbing running smoothly.

Final Thoughts

A boiler losing pressure can often be fixed with simple steps, but recurring problems require professional support. From Swanley to Bexley, our team at DAKS Plumbing provides fast, affordable solutions. Don’t wait until a small issue becomes a major breakdown — contact us today for expert help.