Operating Principle; Boiler Control; Temperature Control; Low Water Level Protection - DeDietrich C230 ECO-A 120 Installation, Operating And Service Manual

3 Boiler description
3.3

Operating principle

3.4

Boiler Control

12
Combustion air is drawn into the closed air box through the air inlet
from the plant room (open flued) or from outside via the eccentric flue
system (room sealed) by the boiler gas/air supply fan.
Depending on demand (under the dictates of flow/return sensor and
other external/internal control inputs), the Comfort Master system
determines the boiler output, which directly controls the volume of
mixed gas and air to the premix burner. This mixture is initially ignited
by the combined ignitions & ionization probe, which monitors the state
of the flame. Should the flame be unstable or not ignite within the pre-
set safety time cycle, the controls will shut the boiler down requiring
manual intervention to reset the boiler. The digital display will indicate
a flashing fault code confirming the reason for the failure.
The products of combustion in the form of hot flue gases are forced
through the heat exchanger transferring their heat to the system water
(the flue gas temperature is reduced to approximately 9
above the temperature of the system return water). Then they are discharged
via the condensate collector, vertically through the 5.9" (150 mm) flue gas
connection to the atmosphere.
Because of the low flue gas exit temperature there will be a vapor cloud
formed at the flue gas terminal - this is not smoke, simply water vapor formed
during the combustion process.
If the controls allow the flow and therefore return temperature to fall below
dew point (131 °F (55 °C)) this water vapor will begin to condense out in the
boiler, transferring its latent heat into the system water, increasing the output
of the boiler without increasing the gas consumption. Condensation formed
within the boiler and flue system is discharged from the boiler to an external
drain via the drain pan/siphon supplied.
3.4.1

Temperature control

The C230 ECO-A is equipped with electronic temperature control
based on flow, return and boiler block temperature sensors. The flow
temperature is adjustable between 68 and 194°F (20 and 90°C)
(factory setting 176°F (80°C)).
3.4.2

Low water level protection

The C230 ECO-A is equipped with low water protection based on
temperature difference measurements and temperature increase
measurements. In some jurisdictions this internal function may not be
acceptable, a separate low water cut-off (LWCO) safety device will be
needed.
This function safeguards the boiler only, a separate control is needed
for the system.
C230 ECO-A
(5 °C)
°F