i have a utility sink in my basement with an in-line pump (not reservoir type) that pumps about 5′ vertically with white pvc into the soil stack via a “u” trap. the pump is rated for 14′ vertical feet, so it should have enough power.
there was little or no movement of water, so i replaced the pump, but the problem has not been fixed. in the line from the pump to the stack is a black pvc fitting 2″ long with arrows on the side indicating flow, and another gray fitting that looks like some sort of check valve. i assume that these are causing blockage somehow as when i took them apart, you couldn’t see thru them.
should i replace them?, and do i even need them (the check/backflow preventers)as i have a trap?
again, the progression is sink/pump/check valve/pvc pipe/”u” trap/soil stack (horizontal at this point)
thanks
Replies
The "check" or "anti backflow valve" is there to prevent the water in the 5' of vertical pipe from flowing back down to the sink after the pump shuts off.
In your case, since you are connected directly into the sewage pipe, in the event of a clogged sewer line, they will also stop sewage from backng up into your sink, since that is the lowest outlet on your system.
thanks for the reply....put this topic in "fests" by accident. do you know what would be a good backflow inhibitor for pvc?
If you eliminate the check valve you may run the risk of short cycling the pump. Depending on the float setting the pump may run continually, or at least on and off, on and off.
it's a switched pump, but i understand what you're sayingthank you
There's no auto start for this pump? I've installed what sounds like you're talking about (called a shellback around here) and it came with an auto switch with a manual override.
At least I think it did, it was about three years ago. I do know that it shut off on its own.
nope, it has a plug, and i wired it to a switch
Okay, i'm thinking I still might go with a backflow preventer.
Even if there was no chance of a backup into the sink, without the check valve you will quite a bit of "hammer". If the discharge pipe remains full of water, the bang of water slamming through an empty pipe will be eliminated.