Need help with overflow plumbing

[mark]

If I'm clear, you have an external overflow with 2 holes.

You're just about already a classic Herbie; just remove the Stockman, cut off the lower drain line from the Tee, adjust the valve so you don't flow anything into the emergency. Since the emergency is normally dry you don't need anything to silence it.

Calculator at bottom of this link (Beananimal) should give you idea of max flow on a 1"

[Raf]

Also, keep in mind that the schedule size of 1" pipe can alter the internal diameter dependent on wall thickness and hence the amount of water it can drain at a maximum....

[Ryan_Lap]

I drained the tank so I could access the plumbing. Ill be connecting the primary as one hose directly to the sump(bulk head) and Ill have the emergency as a separate line going into the sump. Should work out well. Guess Ill find out tonight.

[sphelps]

If you want a standpipe as the secondary drain a durso can handle more flow in emergency situations because if water gets too high it will start a strong siphon better than a stockman. A stockman or HGB can also work but you have to make sure you have enough space that the rising water will submerge the siphon hole in the cap before the tank overflows.

Having two separate lines is the way to go though, tying them together can actually make things pretty noisy as the flow through the primary will create a vacuum effect in the tied in secondary and suck air through that pipe or just cause a loud echo effect.