In Condensing Boilers, this component is placed between the primary heat exchanger and the drain line, and it prevents the exhaust gases from discharging into the condensate drain pipe.
Compared to the early models of Rapid Boilers, which featured a flow switch and thus required a certain water flow rate to produce domestic hot water, manufacturers have equipped modern boilers with a new, more precise mechanism for detecting DHW demand.
The cast iron radiator, or cast iron heater, has excellent thermal inertia properties and is well-suited for use with condensing boilers. It requires low operating temperatures, allowing the condensing boiler to modulate significantly, entering the condensation range.