check valve on fresh water line?

ChrisJ

A friend of ours had her steam boiler repiped two days ago after I had recommend having what was there replaced due to a very poor installation.  The new piping looks great but one thing caught my attention.



There is a swing checkvalve on the makeup water line right before it enters the wet return.  What is the reason for this?  I would think with a backflow preventer the checkvalve doesn't really serve a purpose unless it is somehow to protect the autofeed? 

crash2009

I think that's normal

  I have a McDonnel Miller.  The feeder is installed "ON" the check valve.  Must be for cleaning although I have never cleaned mine.  Further down the line towards the wet return, I have the backflow preventer.

gerry gill

a lot of inspectors

want to see a swing check between the boiler pipe and the backflow preventer due to temperature ratings for many backflow preventers being lower than the steam temperature. I felt the same way the first time i was flagged by an inspector for it missing..now we specifically ask for a watts 9d which is rated for a higher temp..but many areas want a testable backflow..

ChrisJ

checkvalve

Gerry,



Should I install one on my system? I already passed my final inspection but if its something that really matters I don't mind installing it. I have manual feed only.



The backflow preventer I installed is a Watts 0063191 rated for 250F. Sounds like it handles steam fine but I can't find any actual info on it on the web.

gerry gill

in my neck of the woods

anything rated at 250 degrees doesn't need any 'help' from a swing check so i wouldn't bother to alter your set up.