Most boilers have a pressure gauge that should normally sit around 1–1.5 bar when the heating's cold. If it's dropped noticeably below that, here's what's worth checking first.
Check for an obvious cause
A recently bled radiator is a common, harmless reason for a small pressure drop — that's usually nothing to worry about. A sudden, larger drop with no obvious cause is more likely to mean a leak somewhere in the system.
Look for visible leaks
Check around the boiler itself, and near any visible pipework or radiators, for damp patches, drips, or staining. If you find one, that's worth getting looked at rather than just topping up the pressure repeatedly.
Repressurising
Most boilers have a filling loop with instructions printed on or near the boiler for topping up pressure safely. If you're not confident doing this, or the pressure keeps dropping again after topping up, that's a sign of an underlying problem rather than a one-off.
When to call
No heating or hot water, pressure that won't hold after topping up, or any sign of a leak — these are worth a proper call-out rather than repeated DIY fixes. Call 07468 868807 to discuss it.