Drain pump installation for sink? (picture links in text)

[NinjaKicks]

Hello, I have a contractor installing a drain pump (Zoeller model http://imgur.com/LNaBkGQ ) in our basement for a sink. Here is a picture of the unit and setup: http://imgur.com/pb3uIwqhttp://imgur.com/wGrAzjM Today the wife took a bath, heard strange gurgling as water was draining. Afterwards, we noticed that the drain for the drain pump had backed up and water/sewage had come out (we are on a septic field). I don't know if the unit was correctly installed or not, or if this is some other issue (we had some heavy rain yesterday). What concerns me is I don't know what the third pipe connected to the pump is for (the pipe on the left without a check valve). Is that a vent? Sorry if this is a stupid question. The pipes go up and over a cinderblock wall into the crawlspace and connect to the main drain out to the septic field. Here is a picture of the pipes connected to the main drain (the right pipe on the unit with the check valve is the pipe on the right, the left pipe on the unit is the left pipe in the picture): http://imgur.com/8BGpglP

Thanks for any help you guys can provide!

 

[Plumber69]

Check for power first. Breaker could of tripped

 

[Sponsor]

 

[NinjaKicks]

the unit has just been plumbed in, it isn't currently running. I just want to confirm, on a drain pump like the one I pictured, one pipe out is for the discharge and the other pipe out is an air vent, correct? If you look at the last picture http://imgur.com/8BGpglP both of those pipes from the pump tie into the same drain. Is it supposed to do that? Cause it seems like it shouldn't and that backup was from water coming into the incorrectly installed vent pipe.

 

[FullySprinklered]

I've seen a situation where turds floated up in a bathtub after a spell of heavy rain. This was on a hillside residence with a drainfield the size of a postage stamp.

 

[NinjaKicks]

We've never had any problems before with our field even with monumental flash flooding (and this rain wasn't terribly bad). I guess I'm not doing a very good job of explaining. I think the reason it backed up is because the vent pipe is hooked up to the waste pipe versus being hooked up to the main stack or another vent. I color coded the pipes from the unit to where they tie in below. There aren't any other connections along the way and the cast iron they connect to goes directly out to the septic tank:
.

 

[FullySprinklered]

hang on I have one in my basement. Salvage, not hooked in to my house

 

[Reach4]

I would have expected red from the pit to be a vent. Having it run the way it does is odd.

Can you see there is no additional pipe in the red path?

 

[FullySprinklered]

Nope, different pump. You could very well be right. You've got waste in, waste out, and vent. If you have the paperwork on the pump/tank system, that should tell you something. Looks like the pipe sizes change from 1.5 to 2" a couple of times there in your pictures. Might be a clue.

 

[NinjaKicks]

The red pipe goes straight from the unit to where I showed in the second picture, no other connections off of it. At this point I'm about 100% sure plumber incorrectly connected the vent to the main drain out to the septic field, which would explain why it backed up after the bathtub drained. Just wanted to confirm with people more knowledgeable than myself.

 

[Reach4]

What is "it"?

If "it" is the Zoeller pit, I would think that was because the power was not on.

If "it" is the septic field, what would that mean?

 

[NinjaKicks]

Sorry, I should have been more specific. The drain connected to the sump pit (circled below) is what backed up. It was previously uncapped. I'm guessing the tub drained and washed back into the incorrectly installed vent pipe on the sump pit. The contractors didn't have it plugged in, but if it was installed correctly, the only way for waste water to get in would be through the discharge which has a check valve on it. the water got in through the incorrectly installed vent attached to the main outlet to the septic field.

 

[Reach4]

Your assessment seems sorta right, except why did the tub water not go into the septic tank? I doubt the reason was the lack of a vent.

 

[NinjaKicks]

It's not that there wasn't a vent, it's that instead of a vent there's now a waste pipe without a check valve connected straight to the main line out to the septic field (which is at a higher grade than the drain pit). In any event, I can conclude that the drain pit has been incorrectly installed, right? I'm not a plumber, but it doesn't seem right that the vent pipe should be connected directly in-line with the waste discharge pipe.

 

[Terry]

The lav gets vented "before" it enters the sump basin. Venting happens within 42" of the p-trap.
The sump also gets vented through the roof, and a line with a check valve going to the waste line.
All waste fittings should be for waste. I see a water supply 90 dropping into a wye. That should have been a medium 90.