PRV Temp Ratings

Bob Dempsey

Why are boiler pressure reducing/fill valves, namely Flexcon model Fill-Rite 300FV and Taco model 3350-T, sold as boiler fill valves but they are only rated to 140 degrees? Can these valves be used on residential boiler installations, or are we asking for trouble?

Weezbo

is this prv part of the fill tube?

Weezbo

Usually i dont introduce water over 110 degrees through

the prv,most people would say that is slightly warm comming into a boiler.

Bob Dempsey

The water introduced through the prv is 50 degrees however, a boiler being a closed system, there should be no more water introduced into the system after initial fill(if we've all done our jobs correctly). Therefore, the valve sits with city water on one side that is never flowing, and boiler system water on the other side, being heated to 180-200 degrees throughout the winter. The heat will transfer up that fill water pipe. That's where my question comes from - Why are the valves only rated to 140 degrees and can I use them for a boiler installation as they are sold?

jerry scharf_2

it's not a problem

Bob,

There are enough problems that you don't need to create ones that don't exist. I don't pipe the prv 4" from the actice boiler circuit. Make sure there are a couple feet or more of pipe between the PRV and the place where the water joins the circulator loop, and I guarantee it will not get above 140.

jerry