The secondary fluid flows through the heater shell from bottom to top. In addition, the heated fluid, being of less density than unheated, moves to the top of the shell by convection. These actions result in the hottest water being at the top of the heater - at the heater outlet and at the hot water inlet of the Compensator unit.
Cold water entering the heater flows down through the cold water leg of the Compensator unit and out into the bottom of the heater shell. This flow, through the orifice, draws water down through the hot water leg of the Compensator unit drawing both cold water through and bypass and hot water from the top of the shell, into the hot water leg.
The thermal element "reads" the average temperature of the water in the hot water leg at any given moment and signals the primary (heating) fluid control valve to open or close as necessary to maintain the required heater outlet temperature.
With no demand or load on the heater, the thermal element "sees" only the temperature of the water at the heater outlet and, if the water is at the required temperature, signals the primary control valve to close.
However, the moment that there is a demand for hot water (an increase in load), entering cold water mixes with the hot water in the Compensator unit, cooling the thermal element and thus signalling the primary fluid control valve to open. The need for heat flow to the heater coils is satisfied at once and the heater outlet temperature does not fall below that required.
The Angelery will sub-cool the condensate where the bulk of the incoming water is less than 43°C (110°F). A trap is therefore not required and an orifice plate can be used. Above this temperature a float or bucket trap is used.
Standard materials of construction are as follows:
Shell: Carbon Steel, Copper Lined
Internal Risers: Red Brass
Compensator Assembly: Copper and Bronze
Legs: Carbon Steel
As an alternative Stainless Steel construction is also available.
All units are supplied complete with insulation and cladding.