Strom SBTP21C 21kW 3-Phase Electric Combi Boiler, 663HR

The Strom SBTP21C is a 21kW three-phase electric combi boiler designed to supply wet central heating and on-demand hot water. Screwfix lists an 11L/min hot water flow rate, a serpentine heating element and compatibility with suitable underfloor heating. It is marked suitable for baths, subject to inlet conditions and installation. The compact all-electric design avoids a gas flue and separate domestic hot water storage. A suitably rated three-phase supply and professional sizing are necessary. The SBTP21C model is a three-phase unit with a 21kW nominal rating for both wet central heating and hot water production. Its 11L/min listed hot water flow is lower than the 24kW SBTP24C model, giving buyers a useful comparison for fixture demand. The two-year manufacturer guarantee is subject to registration conditions; an installer should confirm the required three-phase circuit and hydraulic suitability.