I found the scaling on the inside of the 3 way valve while investigating what could have caused one of the flow control pumps to fail. I won't know for sure how extensive the scaling is until I go back and take the system down to change the pump. Thanks, GH
Is there a make-up water system on the loop? I too, have never heard of build up in a closed loop. Bergy
I have read where the original make up water for the system was so offensive that it caused a scaling, ph, and corrosion problem by design. A case of gigo may be the culprit here.
Most antifreeze manufacturers request mix-water that is less than 100 ppm total hardness. However, even at a moderately hard water of 500 ppm this is about 500 mg of solids per Liter of water---which just isn't a whole lot of solid to precipitate out. There is a possibility that it could be corrosion due to an improper antifreeze mix and/or the use of steel piping/valves. The following website provides some commercial and residential jobsite claims of similar problems, although I definitely wouldn't use their recommended deionized water without adjusting the pH and adding corrosive inhibitors. Increase Profits and Reduce Warranty Returns with Proper Antifreeze Mix