Hello, due to corrosion between a galvanized pipe and a cast iron pipe I have had to plug the original drain fitting and reroute two small sink drains from a main line to a 2 in un-vented clean out line. I plan to vent the pipe with an air admittance valve, however it may take me few days to install the valve. My question is how concerned should I be that the drain is currently not vented and won't be for two or three days?