Float-controlled dual flush valve

A dual flush valve apparatus for a toilet that includes a tank for holding water, a valve seat coupled to a toilet bowl, a substantially vertical refill tube, and a chain device which can be pulled largely upwardly, wherein said dual flush valve apparatus includes a pivotable flush member which has an outer portion for connection to said chain device wherein said outer portion can be pulled largely upwardly to pivot said flush member off said seat to flow water out to said toilet bowl, said flush member being pivotable downwardly against said seat to stop said water flow, said flush member including a float part that keeps said flush member in an upwardly pivoted portion when said flush member is pivoted by at least a predetermined amount off said seat, comprising:

• a manually operable control which is operable in a first mode to pull said chain device to pivot said flush member by at least said predetermined amount for a full flush, and which is operable in a second mode to pull said chain device to pivot said flush member by less than said predetermined amount so said flush member tends to immediately pivot down against said seat for a partial flush;
• a float that is vertically slidable along said refill tube and that moves down when water in said tank falls below a predetermined partial flush water level, and a release mechanism which is coupled to said float and which is constructed to be coupled to said flush member independently of said chain device to keep said flush member pivoted off said seat by a partial flush amount which is less than said predetermined amount until said float moves down below said partial flush water level at which time said mechanism releases said float member to allow it to pivot down against said seat.