📋 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.
🔒Written by a Gas Safe registered engineer
Viessmann — Vitodens 100-W
Fault Code b0: Low pressure warning
System pressure approaching minimum — not yet a lockout.
What to do: Repressurise to 1.5–2 bar. If pressure keeps dropping, there may be a system leak.
🔄 You can try resetting
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.
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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
📄
Download ↗Viessmann Vitodens 100-W — Official Manual
Installation & user guide from the manufacturer
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