System schematic of a system with an oil boiler, two radiator central heating zones and a domestic hot water (DHW) cylinder.
The NRG Zone 4 manifold ensures that the boiler receives the coldest possible return water so that it is working under optimum conditions and with optimal efficiency. This is especially important for condensing boilers as it greatly increases the likelihood of the boiler operating in condensing mode, which is by far the most efficient. The manifold also ensures that the central heating zones and the DHW cylinder have access to the warmest possible water for their flow. The manifold also provides the system with a full bypass, meaning that the boiler can always maintain its optimal flowrate.
Wiring: The wiring schematic showes how to wire an NRG Lex. In this example Zone A has a colck and thermostat while Zone B and C have a time and temperature programmer. Using this configuration the oil boiler and its pump will turn on when any of the three zones call for heat.