Overflow problem, any engineer out there?

[Delphinus]

I'm just trying to look at your build thread and understand this. So the sump will sit in a different room, but on the same floor? Ie. not underneath in the basement or something. I assume not underneath like that because then you could just go straight down first and pipe under the bathtub.

So is the sump then 2 rooms away if it is on the same floor but has to bypass over a bathtub? What size plumbing are you using on the drain line?

I would think that for a Herbie, it wouldn't matter if the main drain line had an initial upwards slope because that will just add more backpressure to the line and then you just have the gate valve opened more. But if the emergency drain line has upward slope then as stated already you want to ensure a constant trickle flow to prevent stagnant standing water but I worry that even a trickle would be subject to occasional burping which is going to totally defeat the purpose of having gone Herbie in the first place.

Can you post some pictures or diagrams?