Supplied in kit form, the first flush diverter can be installed on your downpipes with a simple T junction. Simply add and install the length of pipe required to meet your diversion needs. This will be based on the volume of dirty, contaminated water you wish to divert.
Upgrade your first flush system from a 90mm chamber pipe into 100mm so it’s easier to divert the optimum first flush volume. As a general rule, 1 metre of 90mm pipe holds approximately 5.9 litres of water, whereas 1 metre of 100mm pipe holds 8.8 litres of water.
The specially designed, patented First Flush Plus Tee forces fast-flowing water into the diversion chamber, preventing the problem of dirty water “skipping” over the traditional T-junction gap during heavy rainfall.
The Max Chamber Upgrade Kit allows you to upgrade your first flush system from
a 90mm chamber pipe into 100mm making it easier to divert the optimum first flush volume.
To make the max chamber, the kit includes:
Generally speaking, the more water you divert, the better the quality of the rainwater that ends up in your tank. However, diverting more rainwater than necessary can lead to volume shortages, so it’s important to calculate your diversion needs, and divert water accordingly.
The following formulas offer general guidelines for calculating how much water you should divert:
This calculation will allow you to determine what length and size pipe or pipes you need for your diversion chambers.
First Flush diverters help you plan for volume by allowing you to choose your catchment volume with custom catchment size and/ or an advanced release valve.
First Flush Diverters help divert the first flush, through their design. They are installed using a T junction or high flow inlet to which the diversion chamber is fitted. As the chamber fills with the initial dirty water from your roof, a ball rises until it seals the inlet, allowing the rest of your rainwater, which is much cleaner, to flow directly to your tank.
The length of the chamber is dependent upon your desired diversion volume.
To make Max Chamber:
If you’re using the Max Chamber adaptor to create your first flush diversion chamber, you will need to determine the length of 100mm pipe you require. As a general guide, 1 metre of 100mm pipe holds 8.8 litres of water. 3 feet of 4” pipe holds 2 gallons of water. Ensure all cut edges are clean and smooth.
If you aren’t using the Max Chamber adaptor, you will need to determine the length of 90mm (80mm or 3”) pipe required for your first flush diversion chamber. As a rough guide, 1 metre of 90mm pipe holds approximately 5.9 litres of water. 1 metre of 80mm pipe holds approximately 4.6 litres of water. 3 feet of 3” pipe holds 1.2 gallons of water. Ensure all cut edges are clean and smooth.
The First Flush Plus tee can be installed in the horizontal or vertical orientation to suit your installation. The outlet must be accessible for maintenance and inspection. (Refer to Figures 1a, 1b and 1c for suggested installation orientations).
Select the orientation of the First Flush Plus tee appropriate for your chosen installation point. This will determine which socket on the First Flush Plus tee will attach to your diversion chamber.
Measure your existing downpipe and cut to create space for the First Flush Plus tee. The outlet of your diverter must sit at least 150mm (6”) from the ground when fully assembled, so select your installation point and measure and cut accordingly. Ensure all cut edges are clean and smooth. Install your First Flush Plus tee in place by applying solvent weld glue to the sockets and pipe. Insert the pipe into the sockets or socket adaptors at either end of the First Flush Plus tee.
Apply solvent weld glue to the threaded end coupling socket and one end of your diversion chamber pipe and insert it firmly into the end coupling. If you’re using 90mm pipe, you will need to use the 90mm end coupling socket (and adaptors if required). If you’re using the Max Chamber adaptor, you will need to use the 100mm end coupling socket (and adaptors if required).
Apply solvent weld glue to the Max Chamber adaptor and glue it onto the upper end of your diversion chamber. If you aren’t using the Max Chamber adaptor you can disregard this step.
Orient the ball seat so it will fit inside the First Flush Plus tee socket that will attach to your diversion chamber. If you’re using 3” pipe for your diversion chamber, you will need to snap off the outer spacer ring from the ball seat.
With the ball seat in place, apply solvent weld glue to the upper end of your diversion chamber into your First Flush Plus tee. The upper end of your diversion chamber will be either 90mm pipe or the Max Chamber adaptor, depending on which configuration you are using. Insert the upper end of your diversion chamber into the First Flush Plus tee. If you are using the Max Chamber adaptor, make sure you align the indicator mark to point away from the mounting wall. This will ensure your First Flush unit will sit flush on the wall.
Attach to the wall using the supplied brackets, supporting the unit until it is fully secured. The smaller brackets are for the standard diversion chamber. The larger brackets are for the Max Chamber. The upper bracket should sit directly under the First Flush Plus tee where it will hold the weight of the unit.
Place the ball inside your first flush diversion chamber through the end coupling and firmly screw the transparent, rapid release exit funnel with O-ring onto the end coupling to ensure a good seal.
Select the appropriate flow control washer and fit it into the hose connector with the side marked “TOP” showing. Start by using the flow control valves with the smallest gauge hole (lowest number). Try a larger gauge if experiencing blockages. Save the remaining flow control valves for possible future use. Insert the plastic filter screen in through the base of the Transparent, Rapid Release Exit Funnel and secure by attaching the hose connector and flow control valve.
It is important to ensure that your first flush diverter outlet remains clear of any debris. If your outlet becomes blocked, the chamber will not empty and the first flush of water will not be diverted when it rains.
To ensure the flow of water through your diverter’s outlet, periodically unscrew the outlet to allow debris to fall out. If the diversion chamber is full of water, take care as it empties.
Remove the hose connector, flow control washer, and filter screen and hose or wash the screen with clean water. Check the flow control washer for any blockages and remove and clean as necessary.
For best results and minimal maintenance, we recommend installing rain heads such as our Leaf Eater rain heads on all your downpipes to limit the volume and number of leaves and debris that reach your first flush diverter.