Why Does My Boiler Keep Losing Pressure?
If your boiler keeps losing pressure even after you top it back up, there is almost always an underlying fault that has not been fixed. Repeated repressurising is a symptom, not the solution.
Why repeated pressure loss matters
A one-off pressure drop after bleeding radiators can happen, but repeated loss points to water escaping from the system or a component failing to manage pressure correctly.
How this differs from a simple low-pressure warning
If the pressure drops once and then stays stable, the fix may be straightforward. If it keeps falling every few days or every time the heating runs, the fault needs tracing properly.
When to book a repair visit
If the system needs regular top-ups, the boiler is locking out or the discharge pipe is dripping, it is time to book diagnosis rather than keep repressurising it.
Do not DIY these repairs
- Do not keep topping the pressure up as the long-term answer
- Do not open the casing to inspect internal pressure parts
- Do not replace sealed-system components yourself
What usually fixes it
- Finding and repairing a hidden system leak
- Replacing a failed expansion vessel
- Replacing a faulty pressure relief component
Frequently asked questions
Open a topic to read the full details.
Is this something I should ignore for now?
No. Boiler and heating faults usually get worse if the underlying cause is left unresolved, especially if the boiler is shutting down or leaking.
Can I safely diagnose the internal fault myself?
No. You can carry out basic visual checks, but internal boiler parts and gas-related work should be left to a qualified engineer.
Will this automatically mean I need a new boiler?
Not always. Many common faults can be repaired once the real cause has been identified.
Book a boiler repair visit
If the problem keeps returning or your heating has stopped, book a proper diagnosis from a Gas Safe engineer.