There is a maximum amount of flow (volume of water in litres per minute – LPM) that any water system can deliver in one minute. This is determined by the water supply/pressure from the water supplier and the pipe size.
You can determine what the maximum flow is by a simple jug test and then set the “Adjustment Amount” on the “Auto Valve” to be about 10% lower than the maximum.
Self Jug Test
Take a jug with a known volume – ideally a one litre jug. For a timed period of one minute turn a cold water tap on fully and fill and empty the jug, counting the number of jugs emptied. The number of litres it fills in one minute will be the maximum flow per minute in litres per minute (LPM). It will probably be about 6-12 LPM.
The “Excess Flow” can then be set between 8 and 40 litres per minute to suit the water supply and usage.
Should there then be any form of unrestricted flow, like a ruptured or burst pipe, the “Auto Valve” will turn the water supply off and the “Excess Flow” LED will light up. It will remain off until the “Reset” is pressed.
To change the “Flow Limit” locate the “Trimming Tool” supplied with the “Auto Valve” and insert it into the “Adjust Amount” hole on the front of the “Auto Valve” ( See picture below).
When turned completely to the left (anti-clockwise) the flow will be 8 Litres per minute (LPM).
When turned completely to the right (clockwise) the flow will be approx. 36 Litres per minute (LPM).
Set the limit just below the maximum, that way if a serious rupture occurs and it tries to take the maximum full flow, it will shut down in 12 seconds. Repeat the exercise a few times to ensure you have it adjusted correctly. Remember you always have the one hour bypass feature for such occasions.