Grant Eco Utility System Boiler. Grant exceptionally quiet Vortex Eco Utility boilers are competitively priced condensing appliances. They are very efficient with a SEDBUK 'A' rating, and have the latest version of the Grant Vortex stainless steel heat exchanger and baffle system. Eco Utility models come in outputs ranging from 15-35kW. Sealed System Models Grant Vortex Eco Utility boilers are also available in sealed system versions. These include a factory fitted expansion vessel, filling loop, pressure gauge, automatic air vent, pressure relief valve and high efficiency circulating pump, enabling boilers to be installed without the need for a feed and expansion tank in the loft.