A guide to using Reverse Flow Method to detect water leaks
February 8, 2018
When we initially launched our Boundary Box Adapter Kits, it soon became clear that not all water companies had installed “Ferret friendly” boundary boxes (do read our recent blog on using boundary boxes for leak detection).
To mitigate this, ferret set about finding another way to locate a leak without being able to get into the pipe at the boundary box. If a plumber or leakage specialist is able to gain access to the property and in particular the mains water riser and Internal Stop Valve, we have a solution – using a Reverse Flow Hose Kit. Please refer to the following IMAGE which provides photos and notes on the main components of this technique.
The advantages of using a Reverse Flow Hose Kit
The Reverse Flow Hose Kit can be used as follows:- • Only when there is an External Stop Valve in a boundary or manifold meter box which allows our unique Boundary Box Adapter to be fitted. This allows controlled discharge of water through a breather hose and Valve when the Ferret Head is being pushed from the property back towards the leak. See IMAGE 1. • Access to the mains water riser inside the property is required, allowing connection of the Ferret outlet hose once the internal stop valve has been removed (See IMAGE). • The mains water supply for the operation of the Ferret Leak Locator is obtained from the quick release connection on the Boundary Box Adapter (which fits any manifold meter box). Water is first fed through a short hose with a non-return valve, to prevent any risk of back-flow contamination of the public water supply. One or more extension hoses, supplied in 30 metre lengths, are then used to make a final connection to the Ferret inside the property. • When using the breather hose to allow the water to discharge from the water supply pipe, we have in addition developed a unique non-return valve key which depresses the small valve inside the meter manifold, allowing the water to escape safely to ground.
The Ferret Leak Locator can then be operated in the normal way from inside the property towards a suspect leak as shown in the IMAGE.
How the Ferret Leak Locator Works
The Ferret system uses simple hydraulic principles to find the exact position of the leak. The upstream water pressure within the pipe is used to drive the Ferret Head towards the leak position. No external power source is required.
How the Ferret Head or Balloon works
The Ferret Head is an integral part of the Ferret Leak Locator. The Ferret Head is essentially a strong balloon (see previous blogs) connected to an umbilical cord.
This balloon is inflated in the pipe and is then pushed along by the water pressure behind it. By carefully balancing water pressures in the balloon and the water behind it – the Ferret Head moves along the pipe until it reaches the point of the leak, at which point the water escapes and the Ferret Head will stop moving. For very small leaks, in some cases just a slow drip, the leak position can still be located by homing in by “pressure testing” several metres of supply pipe at a time. By moving the Ferret Head backwards and forwards an exact location can be determined.
By adding an optional sonde to the system just behind the Ferret Head, locating leak positions to within a few millimetres can be achieved
The Reverse Flow Hose Kit
This kit essentially includes three items:- • Inlet extension hoses – these make for fast and efficient supply of mains water pressure from the Boundary Box Adapter installed in the meter box to the Ferret Leak Locator positioned inside the property. • Breather Hose – this enables water in the leaking water supply pipe to vent out through the Boundary Box Adapter onto the pavement, preventing the meter box from flooding when the flow is reversed • NRV Key – this is a unique Ferret designed piece of equipment, connected to the Boundary Box Adapter and holds the non return valve open, allowing the flow of water in the pipe to be reversed
The Reverse Flow Hose Kit is a really effective way of gaining access to a leaking water pipe without the need for an excavation – it is a real no-dig solution.
A number of our customers, including water companies and specialist plumbers adopt this technique in an effort to reduce job costs as they do not require an “opening notice” in public highway with the attendant costs of doing so.
If you’d like anymore assistance on how to use the pipe leak detection system or using a Reverse Flow Hose Kit, get in touch by calling us on 0800 292 2835 or you can fill in our contact form and we will get back to you.