Riello DB 4 LSM C13 Installation, Use And Maintenance Instructions page 75

6.2.4 Checking and cleaning
The operator must use the required equipment
during maintenance.
Combustion
The optimum calibration of the burner requires an analysis of the
flue gases.
Significant differences with respect to the previous measure-
ments indicate the points where most care should be exercised
during maintenance.
Combustion head
Open the burner and make sure that all components of the
combustion head are in good condition, not deformed by the
high temperatures, free of impurities from the surroundings
and correctly positioned.
Burner
Clean the outside of the burner.
Fan
Check to make sure that no dust has accumulated inside the fan
or on its blades, as this condition will cause a reduction in the air
flow rate and provoke polluting combustion.
Boiler
Clean the boiler as indicated in its accompanying instructions, es-
pecially to maintain all the original combustion characteristics.
Flame sensor
Minimum current for correct working is 70 µA.
If the value is lower, it could be due to:
– Exhausted sensor;
– Low voltage (lower than 187 V);
– Bad regulation of the burner.
In order to measure the current, use a 100 µA d.c. microammeter
connected in series to the sensor, as in the diagram, with a ca-
pacitor of 100 µF - 1V d.c. in parallel with the instrument (Fig. 40).
D1143
Filters
Check the filtering baskets on line and at nozzle present in the
system.
Clean or replace if necessary.
If rust or other impurities are observed inside the pump, use a
separate pump to lift any water and other impurities that may
have deposited on the bottom of the tank.
Nozzles
It is advisable to replace nozzles once a year during periodical
maintenance.
Do not clean the nozzle openings.
Hoses
Check that these are in good conditions.
Fuel tank
Approximately every 5 years, suck any water on the bottom of the
tank using a separate pump.
Combustion
In case the combustion values found at the beginning of the inter-
vention do not respect the standards in force or, in any case, do
not correspond to a proper combustion, contact the Technical As-
sistance Service in order to carry out the necessary adjustments.
EN 267
Theoretical max CO
0 % O
2
15.2
Gas leaks
Make sure that there are no gas leaks on the pipe between the
gas meter and the burner.
Gas filter
Change the gas filter when it is dirty.
Combustion
In case the combustion values found at the beginning of the inter-
vention do not respect the standards in force or, in any case, do
not correspond to a proper combustion, contact the Technical As-
sistance Service in order to carry out the necessary adjustments.
Fig. 40
EN 676
Theoretical max
CO
GAS
0 % O
G 20 11.7
G 25 11.5
G 30 14.0
G 31 13.7
LIGHT OIL OPERATION
Air excess
Max. output. Min. output
 1.2
CO % Calibration
2
2
 = 1.2
12.6
GAS OPERATION
Air excess
Max. output. Max. output.
  1.2
CO % Calibration
2
2
 = 1.2
2
9.7
9.5
11.6
11.4
CO
 1.3
mg/kWh
 = 1.3
 1000
11.5
Tab. N
CO
  1.3
mg/kWh
 = 1.3
 1000
9
 1000
8.8
 1000
10.7
 1000
10.5
Tab. O