studor vent (aav) quit working
I installed a studor vent on a kitchen sink 18 months ago w/ no problems. Recently the sink started slow draining and backing up. When I unscrewed the studor valve it would drain fine, so I figured the vent had failed, bought a new one and installed, and still getting same problem. This is the only AAV in the house, all other vents are atmospheric (through roof) and we are in a single story house. Any ideas on what could have changed after 18 months of use that would render these vents ineffective after they had been working just fine? Any help would be MUCH appreciated. And yes, these are code compliant where I live. Thanks much!