Low pressure is the single most common reason a boiler stops heating, and in many cases it's something you can put right yourself.
The correct pressure
Aim for 1 to 1.5 bar with the system cold. Anything under 0.7 bar will typically trigger a lockout; anything over 2.5 bar cold risks the pressure relief valve discharging.
Re-pressurising step by step
With the boiler switched off and the system cold:
- Find the filling loop, usually a braided silver hose or a built-in key beneath the boiler.
- Open both valves slowly and listen for water entering the system.
- Watch the gauge and close both valves at around 1.2 bar.
- Reset the boiler and check it fires.
When it isn't a DIY job
If pressure drops again within days, or you can't find a filling loop, stop there and book an engineer. If you'd rather not tackle it yourself, we cover Birmingham and surrounding areas, seven days a week.
Want it done for you?
If you want your plumbing or heating problem fixed professionally for you, contact Matt Plumbing & Heating today for fast, reliable service across Birmingham and surrounding areas.
