Posted by Harold Kestenholz - Hydronic Network on June 14, 2001 at 10:19:37:
In Reply to: Mineral build up posted by Tim on June 14, 2001 at 08:50:19:
There is a conflict between normal and recommended. Normal plumber's concepts expect a leak to occur, so they leave a pressure reducing valve from a domestic water feed line open against manufacturer's recommendations on the tag.
http://fhaspapp.ittind.com/literature/files/610.pdf
Page 3 bottom.
This permits leaks to be covered up by feeding water into the system. Minerals build up at leaking joints to tell you after the fact that minerals are building up in your system due to fresh water being introduced.
Recommended means prevention of mineral buildup by installing a low water cutoff to tell when there was a leak and keeping the hand valve closed before the presure reducing valve. This prevents a continuous flow of mineral ppm to make an inch of lime in the bottom of a boiler in a year - causing early burnout.
There is a leak at the ball valve threads or some flux (which should not be at a threaded fitting) that needs to be fixed. Teflon tape is not recommended as sealant as it may require overtightening and cause a leak.
The 'normal' practice is not used by refrigeration and air conditioning technicians because they are not allowed to keep a bottle of refrigerant attached to a leaky system through a pressure reducing valve - by EPA mandate. The recommended concept of 'sealed system' has more meaning to a cooling system as it is not 'just water' being lost.
But here is a typical conversation.
http://forums.thathomesite.com/forums/load/hvac/msg0307340812532.html