I have had to replace the smart valve three times now this time before they did it i found this web page http://www.eccohtg.com/links/ECCO%20News%205/Armstrong%20SB%20-%20File%20No.%20SVB01-1.htm it gave a solution with a protective shield. It says that moisture is the problem. I really hope this time it is fixed for good im tired of fixing this every year.