Question: do npt fittings need sealant?
Answer: Because NPT fittings seal at the threads instead of at a flare or at the hex, thread sealant is the only type of gasket you can use. We at Pegasus recommend a liquid or paste sealant such as Loctite 565 PST Thread Sealant (Part No. LT-37396) instead of plumber's tape. ... Never use a torque wrench to tighten NPT fittings!