# American Standard H2Option Dual Flush Toilet: How the Flush Works

The H2Option is a two\-piece dual flush toilet from American Standard: 4\.8 litres for a full flush and 3\.5 for a partial one\. Press either button and watch the flush valve lift, the tank empty through the PowerWash rim and siphon jet, and the fill valve top it back up\. Live readouts show the litres, the flow and the refill time\.

By Numa

Topic: Machines

[Open the interactive Jig](https://ask.jig.com/j/jLSLiL8MaFTM)

## Guide

### 1. American Standard H2Option

A two\-piece dual flush toilet\. Press the big half of the button for a 4\.8 litre full flush, or the small half for a 3\.5 litre partial flush\. Drag empty space to turn it\.

### 2. Lift the tank lid

Inside, the blue dual flush valve stands over the 2 inch outlet\. The fill valve and its yellow float cup keep the tank topped up\. Tap the lid to put it back\.

### 3. Cut through the middle

Water runs from the tank into the PowerWash rim and the siphon jet\. The 2 inch trapway always holds a water seal that keeps drain smells out\.

### 4. Full flush: 4\.8 litres

The button lifts the flush valve off its seal\. Water rushes through the rim and the siphon jet, fills the trapway and starts a siphon that empties the bowl with a gurgle\.

Refilling is shown three times faster than real time\.

### 5. Partial flush: 3\.5 litres

The small half lets the valve drop back sooner, so only 3\.5 litres leave the tank\. That is still enough to start the siphon\.

Refilling is shown three times faster than real time\.

### 6. Refill and the float cup

As the water drops, the float cup drops and opens the fill valve\. Rising water lifts it until the valve shuts with a click\. Drag the float up to stop the fill\.

Refilling is shown three times faster than real time\.

### 7. A running toilet

If the flush valve does not sit flat on its seal, water trickles into the bowl all day and the fill valve keeps topping up\. Tap the blue valve to reseat it\.

### 8. Ready for the next flush

The tank is full again and the bowl is back at its water seal\. Flush, lift the lid, or turn the toilet to look at it from any side\.