What is the best chemical pipe cleaner and how do you use it? I have a outdoor wood furnace hydronic system and I neglected adding rust inhibitor. Chunks are breaking off and screwing up the zone valve. Does anybody out there have any idea?:D

Contact these folks and ask for a dealer in your area that sells there products.
They make good stuff.

Name: Hercules Chemical Co. Inc.
Address: 111 South St.
Passaic, NJ 07055-9100
UNITED STATES

Phone: (800) 221-9330
Fax: (800) 333-3456

Web site

Welcome to Hercules (http://www.herchem.com)

Contact these folks and ask for a dealer in your area that sells there products.
They make good stuff.

Name: Hercules Chemical Co., Inc.
Address: 111 South St.
Passaic, NJ 07055-9100
UNITED STATES

Phone: (800) 221-9330
Fax: (800) 333-3456

Web site

Welcome to Hercules (http://www.herchem.com)
Thank you HVAC but you see I'm in Canada and I was wondering about Home Depot.

Wow I have no idea about Home Depot. I have never bought or never will buy and HVAC stuff there. If you call the number posted in the information I sent you they will tell you where you can get there product or a similar product in Canada.