I have been having trouble with a fill valve for an outdoor water pond. The valve is regular toilet fill valve in a 6″ diameter PVC enclosure used to auto fill the pond.
I replaced the valve several months ago with a Fluidmaster fill valve (400A). Afterwards, the pond kept running dry even though the valve was working properly. After much troubleshooting, I finally figured out that air bubbles were entering the pond’s fill pipe from the valve. The bubbles slowly collect in the pipe and form an air gap. My solution was to replace the valve with a valve that is completely submerged thereby eliminating the chance of air being drawn in. I purchased a Delta FV75 which works with water pressure on a diaphram. The problem with this is the valve needs to have breather vents left open to atmospheric presure and I am unable to do that.
Does anyone know of a valve that will fit in the enclosure that will not draw in air? The original valve unit was a totally submerged type, but it is long gone and I don’t know what brand it was.
As for the valve that you can use, sorry none comes to mind …. But, by law you MUST have an air gap between the overflow level of the pond and the inlet valve. A submerged float valve in a pond is asking for trouble with the domestic water supply, and illegal in most countrys, if not all.