Hey instead of using the test cock which isn't the best way to blowout a system. On the downside outflow of the backflow cut out a piece of pvc and install a 1x1x3/4 or 1/2 tee. You can then use that to blowout your system with no problems from now on. Don't forget to buy a 3/4 or 1/2 plug as well make sure its threaded the tee and the plug. <blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by djlachance...
