Anti siphon valve for black tank flush
2012 FR Surveyor SV264RK. Can't seem to locate anti-siphon valve for black tank flush. I know what it looks like but it is not under sink in bathroom. When I use BT Flush I get water running from b...
Forum Discussion
enblethen wrote:
OP asked about anti-siphon for black water flush. This is also known as a backflow
preventer. It is in-line with the flush line.
It is not an air gap. The tank is vented through the roof.
The 90 degree black tank flush anti siphon valves with a cap on top are air gaps as the cut away view shows. The brass one shown a few posts below is the same type. That is how they allow the water to drain from the flush lines. If no air vent, water cannot drain out of the lines. Mine cracked year ago and I removed it. And it looked exactly like the cut away view, with vent to atmosphere.
And yes, the tanks are vented.
