Both of the previous are great ideas. Also consider, if it is an older valve, that the main does not close completely, for a variety of possible reasons. We see that alot in older homes. You can confi ... read more
We have written on good bit on this subject: Please take a look at these blogs we wrote!
http://blog.akatlanta.com/2010/11/10-mistakes-not-to-make-when-heating.html
http://blog.akatlanta.com/2010/11/7 ... read more