A fluid heater system for a pumping system comprises a core, a heating element and a sleeve. The core comprises a body made of thermally conductive material, and a plurality of channels formed on an outer periphery of the body. The heating element is disposed within the core. The sleeve surrounds the core adjacent the plurality of channels. The sleeve is formed of a material having a higher strength than the thermally conductive material of the core. In another embodiment, the plurality of channels is chamfered to form a portion of a common outlet plenum and the core includes a temperature sensor bore located proximate the common outlet plenum.