Water treatment company Sentinel Performance Solutions has been sold to a private equity firm for £43 million.

The residential heating and hot water system treatment supplier, based in Runcorn, England, operates in the UK, France, Italy and Germany. Its products clean and prevent corrosion in heating systems. Previous owners The Riverside Company, which invested in the company in August 205, said the sale of the company generated a 3x gross cash-on-cash return.

"We're proud of the work we did with Sentinel," said Riverside managing partner Suzy Kriscunas. "We harnessed Sentinel’s potential, working with management to expand the company’s strong UK position, build sales channels in Benelux, France, Italy and Germany and initiate sales in the US."

In addition to building and strengthening Sentinel’s core hot water system sales, Riverside helped Sentinel capitalize on the growing renewable energy market and build on Sentinel’s environmentally friendly reputation.

"We saw some compelling opportunities to expand Sentinel’s offerings," said Riverside partner Volker Schmidt. "The company now has a comprehensive product line for renewable heating systems, which can be used in solar thermal, air source and ground source heat pump heating systems."