Repair when Not in Use
Determining Whether You Have a 2" or 3" Flush Valve and Flapper
Fluidmaster manufactures a standard or universal size of flush valves with flappers and are among the most common flush valves to be used. All though there are many different types of flush valves most flush valves are interchangeable and depend on the size of the ceramic flush hole that is bored through the tank by the porcelain manufacturer.
Fluidmaster’s Flush Valves use flappers to connect to the flush valve and can be easily replaced by snapping them off and on to the flush valve. These flappers are labeled as 2 inch or 3 inch for their corresponding flush valve size to make it easier for you to select the correct flapper.
The simplest way to determine which Fluidmaster flush valve and flapper to use is to measure the flapper that is already on the flush valve. To identify what size is needed measure the width of the flapper from end to end. If the flapper measures 3 inches across select a 2 inch flapper (like the 502 Fluidmaster model) if the flapper measures 4 inches across select a 3 inch flapper (like the 5403 Fluidmaster model).