Drain plug on water heater
A bit of background: I worked industrial maintenance for 38 years (retired) and have had a successful "HandyMan" business for 8 years now. I work part-time at a local factory with about 700 employees.
A co-worker, who knows I have a camper, asked me the other day if I might have any idea as to why his kitchen sink and bath sink faucets have all but stopped running water. After some discussion he told me that at the beginning of spring he has drained his water heater as someone else told him this would allow any sediment within it to run out with the water. Not a bad idea, BUT--when I asked him "did you put any type of thread sealant on the drain plug before installing the drain plug?" His reply was: " I wrapped the threads with pipe tape (teflon tape)." I told him to remove the aerators on both the kitchen and bath sinks and to look for small white pieces of pipe tape. The next day he brought the kitchen sink aerator in to show me that there were indeed small pieces of pipe tape on the screen of the aerator.
I learned years ago that teflon pipe tape is really a good sealer, but only in certain conditions. IF you use pipe tape on pipe threads and the material that flows through this piping will eventually pass through very small openings, screens, or orifices then you risk having a small piece of pipe tape be torn loose as you tighten the fitting and travel to where it will cause a problem. We had a problem with a huge plastic injection molding machine years ago in that it would not perform on of it's hydraulic functions. After I was sent to look into the problem I asked the operator if anyone had done any recent repair work that would necessitate breaking loose any hydraulic piping or hoses. There had indeed been repairs done just a few days ago. This led me to remove the hydraulic control valve and replace it with a rebuilt one. The machine worked perfectly after that. Upon taking the supposedly bad valve apart I did find a piece of teflon tape in an orifice that prevented the spool from closing off properly.
Moral of the story: Teflon tape will/can be cut when you screw a piece of piping back in and these small pieces of tape can cause problems within your water piping. Use a "dope/cream" type pipe sealant, available at most big box stores.