Burner Adjustment (Gas); Output In 2Nd Stage; Output In 1St Stage; Ignition Output (Gas) - Riello RLS 70 Installation, Use And Maintenance Instructions

6.7

Burner adjustment (gas)

The optimum adjustment of the burner requires an analysis of
flue gases at the boiler outlet.
Adjust in sequence:
1 Burner output in 2nd stage
2 Burner output in 1st stage
3 Output upon ignition
4 Air pressure switch
5 Gas minimum pressure switch
6.7.1

Output in 2nd stage

2nd stage output must be selected within the firing rate range
indicated in page 11.
Turn switch 2)(Fig. 32) to the 2nd stage position: the servomotor
will open the air damper on the value previously set for the light
oil and will control the opening of the 2nd stage VR2 gas valve.
Adjustment of gas delivery
Adjust the gas delivery to the air quantity.
– If delivery needs to be reduced, diminish the adjuster outlet
gas pressure; if it is already very low, slightly close the 2nd
stage VR2 valve.
– If delivery needs to be increased, increase the adjuster outlet
gas pressure.
6.7.2

Output in 1st stage

1st stage output must be selected within the firing rate range
indicated in page 11.
Turn switch 2)(Fig. 32) to the 1st stage position: the servomotor
will close the air damper on the value previously set for the light
oil and will control the opening of the 1st stage VR1 gas valve.
Adjustment of gas delivery
Adjust the gas delivery to the air quantity by operating the 1st
stage VR1 gas valve.
6.7.3

Ignition output (gas)

According to standard EN 676:
Burners with MAX output up to 120 kW
Ignition can occur at the maximum operation output level.
Example:
• max. operation output: 120 kW
• max. output upon ignition:
Burners with MAX output above 120 kW
Ignition must occur at a lower output than the max. operation
output.
If ignition output does not exceed 120 kW, no calculations are
required. If ignition output exceeds 120 kW, the regulatory
standard sets that the value be defined according to the control
box safety time "ts":
– for "ts" = 2s, ignition output must be equal to or lower than 1/
2 of max. operation output;
– for "ts" = 3s, ignition output must be equal to or less than 1/3
of max. operation output.
Start-up, calibration and operation of the burner
120 kW
Example:
MAX operation output of 600 kW.
Ignition output must be equal to or lower than:
• 300 kW con ts = 2s
• 200 kW con ts = 3s
In order to measure the ignition output:
– Remove the UV sensor 29)(Fig. 4 on page 13) (the burner
starts and locks out after the safety time).
– Perform 10 ignitions with consecutive lockouts.
– Read the quantity of gas burned on the meter. This quantity
must be equal to or lower than the quantity given by the
formula:
Example for G 20 gas (10 kWh/Nm
Max operation output, 600 kW
corresponding to 60 Nm
After 10 ignitions with a lockout, the output indicated on the meter
must be equal to or less than:
The ignition output must be adjusted on the gas valve brake.
6.7.4

Operation with LPG - Propane - Butane

The RLS 70 - 100 - 130 burners can operate also with LPG -
Propane-Butane.
In this case it is necessary to replace the six nozzles 2)(Fig. 36)
screwed onto the holes 1)(Fig. 36), which are suitable for natural
gas, with those for LPG-Propane-Butane, provided as standard
with the burner.
Apply the adhesive label for LPG operation near the
characteristics label.
The firing rate and the adjustment of the burner are the same as
for natural gas.
The pressure of the G31 gas (Propane) is shown on page 25.
Gas train: use the train for natural gas, see page 25, with a 1" 1/
2" or 2" diameter.
31 GB
3
Nm /h (max. burner delivery)
360
3
):
3
/h.
3
60: 360 = 0.166 Nm .
D1139
Fig. 36
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