Radiant Floor Heating

[Stan Coryell]

Some of those tankless heaters have a trap primer in the unit. I recall a Bosch? set up that would lose pressure after a couple of weeks because of the trap primer. It was a small system, about a 500 sq ft apartment. An auto fill, expansion tank, and auto vent corrected the issue. How come you are running the pressure so high? 185* and 12 psi should be enough for a two story house.