Was sure the engineer was wrong about upsizing the grease line on this diner job, then the interceptor finally stopped backing up | Commercial Plumbing - Hub Chatter
Was sure the engineer was wrong about upsizing the grease line on this diner job, then the interceptor finally stopped backing up
Last month we were doing a kitchen remodel at a 60 seat diner off Route 9 and the grease interceptor kept backing up every 3 weeks, so the owner was paying $400 a pop for pumping. I told the engineer we just needed to pump more often and stop pouring so much fryer oil down the drain, and he said no, the 2 inch line from the 3 compartment sink was too small and choking the flow before it ever hit the tank. I figured that was nonsense because 2 inch has always worked fine for me on smaller kitchens, and I have run a lot of these lines. He had us swap about 25 feet of it over to 3 inch with a proper slope and a cleanout right at the wall, and that was 6 months back now. They have not called for a pump out since, and the owner said the last guy who came out measured the line and could not believe how fast it drained. So yeah, I was wrong, and it bugs me a little that a guy with cleaner hands than mine knew the flow math better than I did. Any of you ever had to eat crow on a line size call like that, and did it hold up long term?
3 inch for 60 seats and 25 feet of run seems like overkill to me. That tank probably just finally built up enough of a grease cap that it started breaking down on its own, or the cook stopped dumping the fryer oil on Friday nights like he used to. Give it another winter, when the line runs cold and that grease cakes up harder than before. I have seen 2 inch hold fine for years on places bigger than that diner.