On 1 October 1965, Edward Kersting joined the Olsberger Hütte and took over Hans Everken's position as the managing partner. Edward Kersting is Hans Hövener's stepson and was an electrical engineer at the Duisburger Kupferhütte before he joined the Olsberger Hütte.

A new optimistic spirit came to dominate the company under his management, which quickly resulted in him being affectionately called the "Works Boss".

The emerging energy crisis also resulted in the end of the coal- and oil-fuelled single heaters. The age of electric storage heaters commenced.

With the mass production of this technology that had until then been beyond the company's experience, Olsberg was able to add a new string to its bow while simultaneously moving away from the business of mono-structural foundry equipment. Olsberg developed into one of the leading suppliers of these products, which to this day are sold in niche markets all over the world.
Other milestones during his time as the managing partner include the acquisition of Warsteiner Eisenwerke and the take-over of Glockengießerei Junker in Brilon, which was later developed into a hand-moulding foundry in Olsberg.

Olsberg also acquired Jotul-Esch and, shortly after German reunification, Ofen- und Herdfabrik Rathenow and Gießerei- und Ofenbau Königshütte in the Upper Harz.

The controlling interest in Fireplace Kft. in Hungary was purchased in 1998.

The production of cast oven parts was ceased in the foundry. The company then started to focus on the demanding core-intensive grey and spheroid cast iron components for the capital goods industry.

But Edward Kersting wasn't just a businessman. He also supported local associations and assumed functions that were important to the regional and national economies. For instance, he headed the regional association of metals and electrical companies for over 25 years.

Edward Kersting left the operational side of the business and moved to the advisory board on 31 March 2000.