Quick Plumbing Question - Pipe Size

[Eric81]

Starting to plan my plumbing for a 315 I just got.

The two drain pipes are 1.5", but then goes down to a 1" bulkhead. So when I build the drain pipes from the bulkhead to the sump, should I stay at 1", or go back to 1.5"?

Thanks!

 

[Gablami]

For your gravity drain pipes, I don’t think it matters. I’d probably just use 1” most of the way just because it’s easier to work with.

 

[Karliefish]

I have a similar question....I have a 365G tank with four 1” return bulkheads. I’m using Abyzz 200 return pumps that use 1.5” output. So when should I reduce the return pipe from 1.5” down to 1”? Should I do that close to the bulkhead going into the tank or should I reduce from 1.5” down to 1” near the Abyzz pumps?

 

[afuel]

I would drop it to 1” for the pvc right away. 1 1/2” pvc is very bulky for work under a tank and you won’t need the flow rate it provides

 

[DCR]

You will lose a lot of pump capacity if your reduce to 1" right away. I would make a 1-1/2" manifold under the tank and extend multiple 1" return lines up to the tank from that 1-1/2" manifold.

 

[Karliefish]

You will lose a lot of pump capacity if your reduce to 1" right away. I would make a 1-1/2" manifold under the tank and extend multiple 1" return lines up to the tank from that 1-1/2" manifold.

So should I take the 1.5” pipe up as close as I can to the bulkhead before splitting it into two 1” lines? Would that maintain most of my GPH flow form my Abyzz 200’s (Which use 1.5” outlets)?

 

[DCR]

That pump is capable of delivering 2500-3000 gph at full speed with the correct piping. I would generally say you should expect to get about 600-800 gph through a single 1" return line, so four 1" return lines should work great with your Abyzz. You don't need to use 1-1/2" returns if you have four of them. For maximum flow, you would ideally have a 2" discharge manifold off of the pump and then come off it with the four 1" returns. I doubt you really need or want that much flow, so I think you would be fine with a short 1-1/2" manifold and minimize the length of pipe that carries the total pump flow. You can do this by splitting the flow with a tee right near the discharge and place two returns on each side, or just place the manifold very close to the pump discharge.

 

[Karliefish]

That pump is capable of delivering 2500-3000 gph at full speed with the correct piping. I would generally say you should expect to get about 600-800 gph through a single 1" return line, so four 1" return lines should work great with your Abyzz. You don't need to use 1-1/2" returns if you have four of them. For maximum flow, you would ideally have a 2" discharge manifold off of the pump and then come off it with the four 1" returns. I doubt you really need or want that much flow, so I think you would be fine with a short 1-1/2" manifold and minimize the length of pipe that carries the total pump flow. You can do this by splitting the flow with a tee right near the discharge and place two returns on each side, or just place the manifold very close to the pump discharge.

I think I’m following what you are suggesting. I have two Abyzz pumps - not because I need that much flow, but more for redundancy if I should ever have a pump failure. I think I’m going to do what you are suggesting and come-off of each Abyzz 200 with 1.5” pipe and then T-off and then reduce down to 1” pipe. I’ll then have a total of four 1” lines that will go to each of the four returns. Your suggestions have been really helpful - thanks!