Included Bonded Thread Fitting Adapter Review

I bought a check valve in the US and wanted to use it abroad. So I bought a 3/4 G BSP to 3/4 MNPT thread for my Rinnai water heater's shut off valve. The BDP fits my hose well. However, MNPT is not suitable for a check valve (only a few turns inside my valve and three turns outside) as shown in the picture. I wonder if it will be phased out in the future? or the adapter does not fit the check valve (Matsui)? Many Thanks?.

They seemed great and sealed tightly within a few months. Then suddenly water began to spurt through a hole in the brass into the cavity of the wall. So much damage. The brand new hardwood floors in the adjoining storage room are saggy, drywall soaked, what a mess. At first I thought it was leaking under the threads but no - it's clear as day there is a tiny hole from the pin in the fitting. It's too late for a loan now. The product appeared to be of good quality and I was initially very…

I read a couple of reviews on a water heater purchased from Revain that said there were connection problems. Many reviewers said they had to use pieces of Teflon tape to waterproof the fittings. The problem is that the fittings are straight threads, not tapered threads like we use in the US. After a little research I came across these adapters. They work great with one caveat. O-rings actually seal the top of the fitting at the flange. The water heater I bought used this flange to attach the…