I havr installed a pit sewage pump in my basement. I did it myself after much research. I am having an issue with my venting system. I ran a dedicated 2" vent line up into my attick. The one short cut I took was to connect the 2" line into a main 4" line going through the roof. My plan was to try this setup and maybe not have to run the 2" line throgh the roof. I also have a stdor vent on the sink drain main line. This seemed to work great until say November when the weather got a bit cooler. Then I started getting bubbles in the toilet/sink/shower when the pump ran. I know it's a vent issue. If I run the 2" line through the roof, deicated, will this correct my vent issue? One other thing, the pump dedicated vent has a couple of down turns. That is, I could not make it a work out without a couple of 90 turns down. Does this effect the venting? Could water be collected there? Thanks for the help!

Then I started getting bubbles in the toilet/sink/shower when the pump ran. I know it's a vent issue. If I run the 2" line through the roof, deicated, will this correct my vent issue? No! I don't think so.
Before I give you my take on this, let me explain why this vent must be dedicated. Like the house vents it pulls air in. But as the fixtures discharge into the pit it also expels air out. However, reventing back in the attic's acceptable and should bave worked.

One other thing, the pump dedicated vent has a couple of down turns. That is, I could not make it a work out without a couple of 90 turns down. Does this effect the venting? Could water be collected there?
If you've neglected to give proper slope to the vent line or have created traps with these down turns you have located your problem. Water could have collected in these down turns and blocked the vent. Those down turns are the first thing I would check and redo if necessary.
Good luck and let me know what you find. Tom

Thanks! I have created traps! I will check them for water. Can moisture form in the vent line? I can't figure out how it could. Thanks for the help!

Before installing the pump, I did much research, because I hate having these type problems! However, I could not find a way to prevent these "traps" in the vent line due to the path. I knew the pump pushed and pulled air. I decided to try tying into the 4" vent in the attick and if that did not work I would cut the other roof hole. Thanks again. I will check it and let you know!

Thanks! I have created traps! I will check them for water. Can moisture form in the vent line? I can't figure out how it could.
The reason we slope all vents back to the drain is so water from rain and condensate won't pool up in the low spots and form a trap.
This will block the vent and make it useless. Go back and redo the low spots. Good luck, Tom

Thanks for the help! So, the "trap" section of my vent line is about 12 feet long. I drilled a hole in the bottom of the pipe today and drained about 5 galons of water! So, I will be correcting the vent pipe. I did notice that when the pump runs, I get some slight movement of water in the toilet and a some pressure in the vent line. Does this indicate the studor vents are not enough venting?

Repair the vent and get back to me if you still have a problem. There will be pressure in the vent as the fixtures discharge into the pit.
Regards, Tom