I have a Navien 240 boiler/hot water combo from which I heat 2 zones (radiant heat on one floor, baseboards on the other). It was installed after Hurricane Sandy by a plumber who has since lost his license. I have been told by several people over the years that the unit was installed with major errors. I've also had nothing but problems with it (constantly shutting down due to error codes, a ton of air in the unit etc). With the cold snap currently in the northeast it has gotten worse. It shut off in the middle of the night and by the time I was awoken by the cold, all of my pipes in the crawl space had frozen (the pipes are heated by a length of slant fin in the crawl space controlled by the second floor thermostat). The plumber I had in today was horrified by:


The unit has no pressure reducing valve (there are pressure issues and the unit constantly throws the pressure relief valve
The unit does not have a dedicated line. It is fed only off the auto feed

Am I missing something? Does the Navien not need a PRV? I really have a tough time accepting the fact that a licensed plumber would do this to a homeowner, especially truing to recover after Sandy

What do you mean by, "it has no dedicated line, it is fed by the auto fill valve". An automatic filler is normally a pressure reducing valve that limits the pressure in the system to the required level.

Navien ch 240 has a built in auto feeder pressure reducer I do not use the built in one due to them being problematic