The 5 Series represents some of our best features and efficiencies. Its advanced components offer a level of comfort and savings that’s far greater than any ordinary system and among the geothermal industry’s highest. The 504W11 high temperature hydronic heat pump with OptiHeat technology is our geothermal solution for boiler replacement. Capable of delivering up to 150°F leaving hot water, this system is perfect for baseboard radiator systems, underfloor radiant applications, overfloor radiant applications, and fan coils. Typical geothermal hydronic systems are limited to water temperatures around 130°F which can make replacing fossil fuel boilers difficult. This system has been designed specifically to meet these higher temperature requirements and makes upgrading to a WaterFurnace system easier. It utilizes an additional heat exchanger to divert excess heat and reinjects it into the system, creating higher exiting water temperatures and optimum compressor operating conditions. Smaller loads are required and result in the ultimate in efficiency. The 5 Series upholds the standards we’ve set over three decades and the trust associated with the WaterFurnace name. Every unit is computer run-tested to ensure flawless performance at start-up – and in the unlikely event of a malfunction, they’re backed by the best warranties in the industry. Choose a geothermal system that’s Smarter from the Ground Up.