Siphon Breaker Vent Pipe Location (Sketch attached) Say I need to maintain a roughly constant liquid level in a tank (T1 in attached image), one way is to have a U-loop on the drain pipe. Problem is, this can get a siphon started in the geometry shown & entire T1 empties into T2. Not good. One way to break a siphon is to use a vent pipe (V1 / V2 / V3) as a siphon breaker (I think). Question: Does it matter if V1, V2 or V3 is the siphon breaker pipe location? I think all ought to work but wanted to check. Intuitively V2 seems best, but sometimes mechanical constraints might make V2 hard to implement.