WHALE Rapid Heat Gas & Electric Water Heater. The Whale Rapid Heat 8L Water Heater gives you extra fast heat up times as well as the flexibility of versatile gas and or electric running options. Easy to use control panel with choice of settings. Lightweight unit weighs only 8kg (dry weight). Robust insulation retains heat for longer. New pressure relief valve with drain function, drains entire water system faster. Easy installation. 3 year warranty. Complete with retro fit kit for replacement of Carver Cascade Water Heater. PLEASE NOTE: All Whale Water Heaters must be installed and serviced by a fully qualified gas engineer in accordance with the appropriate installation instructions.