Toilet flapper — dual-flush chain tangle keeps toilet running
Running toilet
On dual-flush tanks, a tangled flapper chain can hold the toilet flapper open so the toilet keeps running even when the trip lever feels fine.
A dual-flush tank has more chain and float hardware in a small space. If the toilet flapper chain loops on a float or the trip lever arm, the flapper stays cracked open and the toilet keeps running.
Untangle the dual-flush flapper chain when the toilet keeps running
- Lift the lid and flush both buttons or lever positions while watching the flapper — note if a chain hangs up on the overflow, float, or neighboring link.
- Straighten the chain so it rises cleanly with a little slack at rest (about half an inch) — no loops under the flapper edge.
- Confirm half-flush and full-flush links (if separate) do not cross or twist around each other.
- Flush again. Water should stop within a few seconds once the flapper drops square on the seat.
If the chain is untangled but you are not sure how much slack to leave, see how much slack a toilet flapper chain should have.
Honest stop: if the flapper is warped, the seat is eroded, or chains keep retangling on a worn mount, replace the flapper or dual-flush kit — do not keep shortening chain until it binds.
More help
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- Related fixes elsewhere: Dual-flush float can still keep the flapper open · Adjust toilet flapper chain slack