Yes it is the thread size.
I need to replace the automatic air vent valves in my domestic hydronic heating system and was going to use the Watts FV-4M1 valves.....I noticed that there are 1/8" and 1/4" sizes, does this relate to the thread size, as I do not know which ones to order.....is there a common size in a domestic system?
Many thanks, Martin
Thanks cwhyu2.......do you know if one size is more common than the other?
1/8 is the most common that I have worked with but there are other factors as in is it metric or iron pipe size,and is it base board or iron radiators.
Last edited by cwhyu2; 08-15-2011 at 03:06 PM.
I am definitely not a pro plumber, but I am a pro crastinator
Basseboard would usually have 1/8" vents, and cast iron radiators 1/4".
Licensed residential and commercial plumber