First Flush Advanced with Max Chamber Upgrade Kit

First Flush Diverters

Divert more contaminants and take greater control over your water volume with this next generation First Flush Advanced Diverter.

This product comes with a Max Chamber Upgrade Kit that 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.

Size 90mm WDDP21

Keep more contaminants out

The First Flush Advanced is more effective at diverting contaminated water. Its patented high-flow inlet largely solves the problem of fast-moving dirty water “skipping” over or around the diverter entrance on traditional T-junction first flush diverters.

Max Chamber Upgrade Kit

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.

Control quality and volume

With its electronic advanced release valve, the First Flush Advanced gives you greater control over how frequently you release your diverted water. Increase your release frequency to maximise water quality or release the dirty water less frequently to maximise stored water volumes.

Upgrade your First Flush volume
with the Max Chamber Upgrade Kit

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:

Max Chamber adaptor
100mm end coupling
100mm pipe wall brackets x 2

Calculate your diversion needs

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:

Areas with low pollution (open fields, no trees, no bird droppings or animal matter, clean environment) = divert 0.5 litres of water per square metre of roof
Areas with higher pollution (leaves and debris, bird droppings, animal matter/carcasses, pollution) = divert at 2 litres of water per square metre of roof.

This calculation will allow you to determine what length and size pipe or pipes you need for your diversion chambers.

The length of pipe required to form your first flush diversion chamber will depend upon how much water you need to isolate and capture.
The following measurements are given as a guide only.

1 metre of 90mm pipe = 5.7 litres

1 metre of 150mm pipe = 18.8 litres

1 metre of 300mm pipe = 72 litres

3 feet of 4″ pipe = 2 gallons

1 metre of 100mm pipe = 8.8 litres

1 metre of 225mm pipe = 45 litres

3 feet of 3″ pipe = 1.5 gallons

3 feet of 12″ pipe = 19 gallons

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.

Learn more about the 4 pillars of designing a Rain Harvesting system.

The Rain Harvesting steps addressed:

	Limit sources of contamination
	Plan for volume
	Filter leaves and debris
	Divert the first flush

	Secure the system
	Manage standing water
	Consider a safety net
	Monitor and maintain

Installation Guide

Download Installation and Specification Guide

Reference Chart
Specifications

The length of the chamber is dependent upon your desired diversion volume.
What's in the box?
- First Flush Plus Tee
- Ball Seat
- Sealing Ball
- End Coupling
- Primary Filter Screen
- Transparent, rapid release exit funnel
- Advanced Release Valve
- 90mm pipe wall brackets x 2
To make Max Chamber:
- Max Chamber adaptor
- 100mm end coupling
- 100mm Pipe Wall Brackets x 2
Tools/materials you may require
- 90mm or 100mm pipe (for diversion chamber)
- Tape measure
- Marker pen
- Saw
- Solvent weld glue
- Screws
- Drill or screwdriver
- 2 new 1.5 volt AAA batteries
Installation
1. 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.
2. 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.
3. 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).
4. 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.
5. 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.
6. 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).
7. 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.
8. 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.
9. 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.
10. 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.
11. Place the ball inside your first flush chamber through the end coupling. Install the Primary Filter Screen, Transparent Rapid Release Exit Funnel with O-ring, and Advanced Release Valve by following the instructions in Figure 2.
Figure 2
Installing and setting up the Advanced Release Valve
2. 1. Insert the Primary Filter into the end of the pipe. It should fit snuggly into the socket on the end of the pipe.
  2. Install the Transparent Rapid Release Exit Funnel, ensuring the o-ring is seated correctly. It should be screwed up firmly to compress the o-ring.
  3. Attach the Advanced Release Valve by first installing the 25mm x 20mm reducing adaptor and washer to the 25mm thread of the screw cap.
  4. Remove the union from the valve and attach to the reducing adaptor with 20mm washer in place.
  5. Attach the valve at the union and orientate dial for easy access.
  6. Remove the waterproof cover from the Advanced Release Valve.
  7. Ensure the reset interval and drain time control knobs are in the “RESET” and “CLOSED” positions. Carefully slide out the battery box and install two new 1.5-volt AAA batteries.
  8. Test the unit by turning the drain time knob to the “OPEN” position. You should hear the sound of the motor within 5 seconds. Turn the drain time knob back to the “CLOSED” position ready for setting.NOTE: If you do not hear the sound of the motor, check that the batteries are installed correctly.
  9. Ensure that the reset interval and drain time knobs are in the “RESET” and “CLOSED” positions. Set your reset interval and drain time according to the tables in the Advanced Release Valve Reset and Drain Time Settings tab, then replace the waterproof cover.NOTE: A long reset interval will mean that the first flush diversion chamber empties less frequently, leading to higher rainwater yield. A short reset interval will mean that the first flush diversion chamber empties more frequently, resulting in a lower water yield. It should be noted, however, that differences in yield are minimal, so set your reset interval as appropriate for the pollution in your area.
Advanced Release Valve Reset and Drain Time Settings

NOTE: The first time you program the Advanced Release Valve it will not begin to operate until after a time delay equal to the setting of the reset interval knob you select. The Advanced Release Valve starts to keep time when you set it. It is important that you set the timer at the hour you want it to operate. For example, if you want the Advanced Release Valve to operate at 07:00AM, you must physically set it at 07:00AM.
Pollution Factors
Maintenance

It’s 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 out through your diverter’s outlet, periodically check the transparent, rapid release exit funnel for any build-up of matter (Remove primary filter and clean if required).

Periodically check that the Advanced Release Valve batteries have charge. This is indicated by the flashing light.

To protect your Advanced Release Valve from freezing or “winterising”, remove the timer prior to the first frost or freeze and store it indoors until spring. Remember to remove the batteries from the battery compartment.

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.