📋 Key Takeaways
- 1.What it means: System pressure approaching minimum — not yet a lockout.
- 2.What to do: Repressurise to 1.5–2 bar. If pressure keeps dropping, there may be a system leak.
- 3.DIY or engineer? You can try one reset after addressing the cause. If it returns, call a Gas Safe engineer.
Fault Code b0: Low pressure warning
System pressure approaching minimum — not yet a lockout.
This fault code can often be cleared by addressing the underlying issue (e.g. repressurising) and pressing the reset button once. If the fault returns after one reset, do not keep resetting — call a Gas Safe engineer to investigate.
Thinking about replacing?
Get a free new boiler quote — takes 2 minutes
Matched with Gas Safe engineers near you. No obligation.
Protect against future repair bills
Boiler cover means no surprise costs when things go wrong
Boiler & heating cover with no call-out fees
24/7 call-out, 4-hour emergency response
Nationwide network of engineers
Prices shown are indicative — actual cost depends on your boiler age and policy type.
Compare repair costs →Full Technical Repair Guide — Pro Members
The component-level repair guide for this fault code is available to Pro subscribers — designed for Gas Safe engineers and heating professionals.
- ✓Exact components to test and replace
- ✓Pressure and temperature diagnostic values
- ✓Common misdiagnosis warnings
- ✓Printable fault diagnosis sheet
- ✓Direct links to genuine spare parts
📞 Get Help Directly
Phone numbers provided in good faith — verify on the manufacturer's official website. PlumbingAdvice.co.uk is not affiliated with any boiler manufacturer.
Was this guide helpful?