Hot Water Reset - Implementation

Implementation

The control system can be made to modulate the supply water temperature in two different ways:

1. By acting as an operating control on the boiler burners, either modulated on/off, high/low fire, or fully modulating fire, depending on the burner construction. When modulating the actual boiler temperature lower, water temperature needs to have a low limit and be maintained above the flue gas condensation temperature for non-condensing type boilers, typically above 60 ⁰C. Condensing type boilers can be made to operate at temperatures below the flue gas condensation limit and raise stated efficiencies from the 85% - 95% range.
2. By acting as an operating control on a three-way powered mixing valve or proportional injection pump system that modulates the supply distribution hot water temperature. The mixing valve or mixing pump system recirculates the return water temperature and adds proportionally supply hot water from the boiler for tempering to achieve the desired supply water temperature.