Concealed toilet cistern not flushing

Concealed cisterns (Geberit, Grohe, Roca, Valsir are common brands) sit behind a tiled wall with only the flush plate visible. Access is usually via a panel or through the flush plate itself.

Try pressing both flush buttons — the smaller button for a half flush, the larger for full. If one works but not the other, only one flush valve seal has failed.

Locate the access panel — some are in a side cabinet, others require removing the flush plate by inserting a thin screwdriver into the slot at the plate's edge and pushing the retaining clips.

With access to the cistern, check the flush rods or cables connecting the flush plate buttons to the flush valve. These can disconnect or snap — reconnecting them costs nothing if that is all it is.

If the flush valve itself has failed (rubber membrane or float perished), replacement kits are available for most branded cisterns for £10–£50. Geberit parts are particularly widely stocked in UK plumbers' merchants.

If you cannot identify the problem or lack access, a plumber familiar with concealed systems should be called — allow £80–£200 depending on complexity.