The warranty (on page 14 of the manual) is clear in that it does not cover defects that are the result of normal wear and tear. So if the tank brokecracked as a result of everyday use, whcih unfortunately, it is prone to do, the warranty doesn't cover this. It must be handled very gently.
You cannot purchase a new tank separately from Canadian Tire.
I contacted the manufacturer, Kaz, Inc, in January 2010 and received information by email on how to purchase a replacement tank directly from them. Unfortunately, due to the terms and conditions of this site, I cannot post theinformation here because it contains the manufacturer's contact information and the cost of the tank.
Please refer to page 12 of the manual for the manufacturer's contact information. I found that email was the best way to contact them.
In order to check the warranty for this product, you can go to www.kaz.com and click on the owner's manual for HWM-450. See page 13 for details of the warranty. You can also call 1-800-477-0457 for further details.
A new tank can only be ordered through the manufacturer's 1-800 number, above.