39
UK
CHECKING COMBUSTION
In order to obtain optimum combustion eciency and to safeguard the environment, we
recommend to check, and regulate combustion using the appropriate instruments.
The most important levels to be checked are:
CO
2
. The level of CO
2
indicates the excess of air during combustion. If the quantity of
air is increased, then the CO
2
% level decreases, while a decrease in combustion air
leads to an increase in CO
2
. Acceptable values would be: 8.5-10% METHANE, 11-12%
B/P.
CO
. This indicates the presence of unburnt gas. CO, as well as lowering the combu-
stion eciency, is also a danger, being a poisonous gas. The presence of CO is thus an
indication of imperfect combustion, and is usually a sign that there is a lack of air during
combustion. Maximum acceptable value is CO = 0.1% volume.
Flue gas temperature
. This represents the loss of heat through the chimney. The hi-
gher is the temperature, the greater is the loss of heat and the lower is the combustion
eciency. If the temperature is too high, then it is necessary to decrease the amount of
gas burnt. Acceptable temperature levels range between 160°C and 220°C.
NOTE: Certain countries may have dierent regulations, and thus dierent admissible
levels from those given
above.
START UP
Check the position of the ignition electrode tips and the position of the control electrode.
Check the correct operation of the gas and air pressure switches. When the thermostatic
line and the gas pressure switch close the control box gives consent for the motor to
be started. During this period the control box conducts a self-test of its correct working
order. If the test is positive then the cycle continues and at the end of the pre-purge
period (TPR - combustion chamber purge) the consent is given to the transformer for
the spark at the electrodes, and to the solenoid valve for opening.
Within the safety time (TS) ame stabilization should occur, otherwise the system goes
in lock-out mode.
PROLONGED SWITCHING OFF
If the burner should remain inactive at length close the gas cock and remove the elec-
trical current from the appliance.
CONVERSION FROM NATURAL GAS TO B/P
A specic burner is not previewed.
