At the Aqua Hot website (
http://www.aquahot.com/eSource/ecom/eSource/default/Manuals.aspx ) you can find manuals by model number. Each has a troubleshooting section. For the electric element there are some voltage checks that can confirm the heating element actually has power to it. Then you disconnect the element and check for continuity.
The electric element does not fail very often, but mine did burn out after 6 years of heavy use. I changed it myself with "supervision" from a friend. One tool that I had to have and was hard to find was a large socket that fit the element.
Roger Burke's forum in the above post was where I got my parts and advice. Since then I've learned Orman Claxton is an active BAC member, Beaver owner, Hydro Hot specialist and he participates on this forum.
On edit: I spelled Orman's name entirely wrong and have fixed it. My apology to him!