Topping Up the Boiler Pressure
Understanding the Issue
Combi boilers rely on water pressure to work correctly. If the pressure drops too low, your heating or hot water may stop working altogether.
Common Signs of Low Pressure
- No heating or hot water
- Error codes on the boiler display
- Pressure gauge below 1 bar
What You Can Do
Most modern boilers allow you to top up the pressure yourself via a filling loop.
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Open both valves slowly until the gauge reaches 1.5 bar
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Close both valves firmly
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Reset the boiler if necessary
Your boiler model may vary—only proceed if the process matches your unit and you feel confident.
Safety Reminder
Do not attempt this if your boiler is leaking, displaying unfamiliar errors, or making unusual noises. Always turn off power and follow the manufacturer’s guidance.
When to Report It
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Pressure continues dropping after top-up
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Boiler won’t restart
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You’re unsure how to proceed