Webstone44443WPR-LF 3/4" IPS Isolator EXP E2 Tankless Water Heater Service Valve Kit with Clean Brass Construction

Had these isolater valves on my Rinnai tankless hot water heater. Installed new in 2016. Tried to cycle the valves, for the first time in Jan., 2021. The hot water valve stem broke inside the valve and the handle, with part of the valve stem, came off in my hand. Water came out through the packing gland. Luckily, I was able to plug the leak with a 1/4-inch brass pipe plug. Valve stem is of really flimsy construction, pinched down where it connects to the ball port inside the valve body.