I was getting error code P1 on my Rheem tankless water heater. I seem to narrow the problem to my inlet water filter but when I took the cap off the filter is still inside. I'm able to spin it with a screw driver and pull it out a bit but doesn't seem to want to come out easy. Is there a trick to get it out?
https://parts.rheem.com/product/RPD-RTG20164AK
https://parts.rheem.com/product/RPD-RTG20164AK