Downpipe filter vs. rain flap

The rain flap diverts the entire water flow with all the dirt and allows the rainwater to splash into the container until it overflows. The collected water thus contains all the dirt that has been rinsed off the roof. When the container is full, the water overflows uncontrollably and floods the surrounding area. Only when the rain flap is closed manually does the flow into the container stop. If the rain flap is forgotten to be opened again, the container will remain empty the next time it rains.

The rain flap is also usually used in combination with open collection containers or rain barrels, which have their own disadvantages and risks. Additional dirt, e.g. leaves, falls directly into the barrel, mosquito larvae swim there in summer and, in the worst case, they also pose a danger to children at play. WISY therefore recommends using closed rain barrels.

Downpipe filter vs. leaf separator

The leaf separator can divert very coarse soiling, but after a short time it also diverts a considerable portion of the water flow, as dirt gets stuck in the separator and the water can no longer flow completely towards the container. If the connected container becomes full, it then overflows uncontrollably and floods the area surrounding the container. Leaf separators can be useful if the aim is to reduce the amount of dirt entering the connected wastewater pipes. For cases in which the rainwater is not to be used.

Diameter of downpipe and downpipe filter

The diameter of the downpipes is determined by the planner so that rain that falls on the roof surfaces can always run off. Like the downpipes, every rainwater filter must also be sufficiently large so that it does not become an obstacle during heavy rainfall.

The applicable standard for rainwater harvesting systems defines that there must be no constriction at any point in the rainwater filter, as otherwise dirts can collect there and form a blockage. This rule also applies to downpipe filters. All WISY filters fulfil this requirement. WISY downpipe filters are suitable for all standard downpipe diameters from 76 mm to 120 mm.

To ensure that the downpipe filter fits your downpipe, WISY offers several versions of each downpipe filter for different pipe diameters. This means you will find the right model for all standard downpipes so that the downpipe filter and downpipe fit together and the filter works perfectly. By their design a blockage of your downpipe is impossible with WISY downpipe filters.

What is important when installing the downpipe filter?

In order to achieve an optimum water yield, the water coming from above should be able to flow further along the inner wall of the pipe as it enters the downpipe filter, from where it is filtered and discharged to the container. To do this, the burr created during sawing should be removed with a file.

Diameter of downpipe and downpipe filter

The diameter of the downpipes is determined by the planner so that rain that falls on the roof surfaces can always run off. Like the downpipes, every rainwater filter must also be sufficiently large so that it does not become an obstacle during heavy rainfall.

The applicable standard for rainwater harvesting systems defines that there must be no constriction at any point in the rainwater filter, as otherwise dirts can collect there and form a blockage. This rule also applies to downpipe filters. All WISY filters fulfil this requirement. WISY downpipe filters are suitable for all standard downpipe diameters from 76 mm to 120 mm.

To ensure that the downpipe filter fits your downpipe, WISY offers several versions of each downpipe filter for different pipe diameters. This means you will find the right model for all standard downpipes so that the downpipe filter and downpipe fit together and the filter works perfectly. By their design a blockage of your downpipe is impossible with WISY downpipe filters.