Why has my push-button toilet flush stopped working?

Push-button flushes fail in a completely different way from lever flushes, because there is a mechanical chain between the button and the valve rather than a direct arm. Anything in that chain can be loose, adjusted wrong or broken, and the symptom is the same — a button that presses and does nothing. Taking the lid off and watching what happens identifies the link that has failed in about ten seconds.

What you'll need

• A torch
• A small screwdriver
• A replacement cable or rod set, if one has broken

Step by step

1. Take the lid off carefully and set it down flat.On a standard cistern, the button unscrews from the lid — usually a knurled ring underneath — before the lid will lift. Take the ring off first, then lift the lid straight up and put it somewhere it cannot be knocked. Cistern lids are china and they break.
2. On a concealed cistern, take the flush plate off instead.The plate unclips or unscrews and the button frame behind it comes out, exposing the mechanism. Photograph the arrangement before removing anything.
3. Press the button and watch the valve.This one observation splits the fault. If the flush valve visibly lifts and the toilet still does not flush properly, the problem is the valve or the water level. If the valve does not move at all, the chain from button to valve has failed.
4. Check the rod or cable connection at the valve.Rod systems have a plastic rod that sits on top of the flush valve, and it commonly falls off or is knocked out of alignment when the lid is refitted. Cable systems have a ferrule that clips into the valve head, and that clips out. Both refit by hand.
5. Check the adjustment.Most rods are length-adjustable by screwing them in or out, and most cables have an adjustable ferrule. The setting matters: too short and pressing the button does not lift the valve far enough; too long and the valve is held partly open all the time, so the cistern runs. Set it so the button has a little free travel before it starts to lift the valve.
6. Check the button frame itself.The buttons sit in a plastic frame with return springs or sprung arms. Limescale and grit jam them, and the plastic pivots break. A jammed button feels solid or stays pressed in; a broken one feels loose and has no resistance. The frame is a cheap spare part on almost every make.
7. Look for a pneumatic system.Some concealed and some standard cisterns use air rather than a rod: pressing the button squeezes a bellows that sends a pulse of air down a small tube to a receiver on the valve. If you find a thin plastic tube rather than a rod or a cable, check the tube is connected at both ends and not kinked or split. A split tube is a very common failure and the tube is replaceable.
8. Test the valve directly.With the linkage aside, lift the flush valve by hand. If the toilet flushes properly, the valve is fine and the fault is definitely in the linkage. If it flushes weakly even when lifted fully by hand, you have a water level or a flush volume problem instead.
9. Refit the lid with the linkage aligned.The commonest way this fault is created is refitting the lid with the rod not seated on the valve. Lower the lid slowly and watch the rod go where it should before tightening the button ring.

If it doesn't work