2 Zoeller 128GPM vs. 1 single 2" PVC Discharge?

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Wolf_22

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I have a basement with 2 Zoeller M267 Waste-Mate's. They're great pumps with 1 being almost 11 or 12 years old and still going strong. Each of these are connected to a single 2" discharge pipe that carries the water out to the city rainwater drain. I'm not exactly sure what the exact distances are that each pump pumps up to and out to before going down into dirt at the edge of my crawlspace, but I believe each sump pit is at a depth of about 2.5-3 feet from the basement slab whereby each pumps up towards my floor joists at a height of about 5' whereby from there, one pump pushes towards a distance of around 25' and the other about 35' until everything finally goes into the ground and out to the street drain. Finally, one of the pumps (the perimeter drain pump) uses one of those rubber flap check valves. The other older pump uses a more secure PVC check valve.

A problem I have is with recoil: whenever each pump pumps at the same time during heavy rains, the perimeter drain discharge line tends to recoil whenever it shuts off. From what I understand, it could be due to the pumps battling each check valve but also because the perimeter drain pump line might have more head pressure. To fix this, I'm told one approach would be to (obviously) secure the lines better as they could all use better stability. The perimeter drain line is held in place by string, but the other is secured by some of the foundation wall itself. So I do plan on securing these better as well as replacing the rubber check valve... But I've also been told that I should consider separating each to use their own dedicated 2" lines or else find a way to feed both into a 3" pipe somehow.

What are some thoughts about how I should approach this? I'm going to be meeting with a contractor soon to discuss all of this because I think I'm leaning towards biting the bullet and installing an additional 2" discharge line that goes in parallel to the existing line which empties into the street drain. It might run me $1k or $2k, but it would give me relief about it all. That, combined with confirming while it's all exposed that nothing is broken with the existing pipe, and securing everything better with replacing the rubber PVC pipe sounds like a good idea to me despite being somewhat costly to do. I'm also thinking that while this work is done, I could get the guys to re-angle the parts of PVC more downward to alleviate as much pressure as possible, which would be another win. By the time everything gets done, each pump would be as efficient as it can be.

Does this all sound like a good idea or do you think it's not really necessary? I just worry that each pump battling each other during the heavier rains is going to result in either something breaking or one or both of the pumps frying themselves out. The rubber check valve has come undone from the pipe twice since it was installed back in November. I've tightened it with my ratchet and it hasn't happened since, but I don't want to leave the house for fear of it popping off and changing that out with a better PVC check valve sounds like the right path to take.

Thanks in advance.
 

Twowaxhack

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I’d change the check valve and secure the line better. Then see how it operates.

Adding a separate drain would be a solution if the changes fail to correct your problem, as you stated.

You’re on the right path IMO. Proceed......
 

Wolf_22

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Okay, good. Seems like a simple and very doable path. I'll get quotes for the new line just in case. (I try to prepare for the worst but hope for the best.) :)
 

Duckbutter

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I resolved a similar problem years ago with an air chamber tee'd above the check, the check valve was shuddering, it was only a single pump though.
 
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