Hi Ho It’s To the Nuthouse I GO!!!
I installed a laundry room in the corner of our basement and have the washing machine on a 13′ run of 2″ pvc to the stack. It’s trapped at the bottom of the 36″ riser directly behind the machine. It’s been in operation for 2 1/2 years now but twice has backed up during tub drain. But there is no blockage- I run it through a full cycle while I’m mopping up the flood and it goes right down. ( I don’t think the stream of profanity scares it into submission, that only works on the dog-sometimes) I’m thinking a random air lock situation ?? If I install an air admittance valve in the run, will that help?
MERRY CHRISTMAS AND HAPPY HOLIDAYS!
Replies
13 feet of 2-inch is way too long for a trap arm. If you don't have a vent close to the trap then that's problem #1. If there is minimal slope on the trap arm then that's problem #2.
David is right.
IIRC a vent should start within 36" of a fixture or drain trap.
Cut the air admittance valve in the drain a foot or so downstream of the stand pipe trap.
Dave
The typical installation is: standpipe, trap, a 90 from the trap to horizontal, into a san tee, the bottom of the tee is the drain, the top of the tee is the vent riser or up to an AAV (higher than the top of the standpipe).