Installation - andrews Maxxflo CWH30/200 Installation Manual, Operation And Maintenance Manual

INSTALLATION

SECTION 3
The series is a direct fired condensing storage water heater which has a DESCRIPTION
stainless steel tank that is heated by up to four burner modules placed outside the tank.
A burner module consists of a stainless steel heat exchanger in which the burner is
placed.
The water heater works according to the loading principle: The water in the bottom of
the tank is led directly through the heat exchanger, heated up and carried back to the top
of the tank. The temperature of the water at the bottom of the tank (return temperature)
is representative of the input heat; the burner modulates on the basis of this return
temperature. The temperature at which the water is supplied to the tank from the heat
exchanger (supply temperature) is kept at the set water heater temperature using pump
modulation.
An important advantage of bringing the heat transfer from outside the tank is that the
output is not influenced by the temperatures that prevail in the tank. As long as draw off
occurs the water from the bottom of the tank to the heat exchanger is almost the same
as the supply cold water temperature. This means the maximum output is maintained
during the heating up period. On the final heating period, when the tank is almost
completely heated up, the return temperature will increase and the burner modulates.
Because the water is pumped round from the lowest point in the tank, the whole tank is
heated up and there are no cool zones.
The water heater is equipped with a maximum of four burner modules dependent on the
model. Each burner module produces a maximum of 30.5 kW output for a set water
heater temperature of 60ºC.
7