baltur BGN 40 LX-V Instruction Manual

Also see for BGN 120 LX: Startup guide

Contents

baltur BGN 40 LX-V Instruction Manual Manual pdf 38 page image

38 ENELECTRICAL CONNECTIONSThe three-phase or single-phase power supply line of the minimum suitable size for the power absorbed by the burnermust be provided with fuse switch. In addition, according to the Standards, a switch on the burner supply line isrequired, arranged outside the boiler room in an easily reachable position.All electrical lines must be protected with a flexible sheath, be firmly fixed and pass far from high-temperature ele-ments. See the diagrams for the electrical connections (line and thermostats).DESCRIPTION OF THE OPERATIONIn the burner, by closing the main circuit breaker if the thermostats are off, the control box is supplied. The fan motor isthus enabled, and its operation determines the pre-ventilation of the combustion chamber. At the same time, thecombustion air damper control motor opens the air damper in the position corresponding to the maximum set.The combustion chamber pre-ventilation step thus occurs with air damper in the high flame position. At the end of thepre-ventilation step, the combustion air damper is restored to the ignition flame position. If the ventilation air pressurecontrol switch detects a sufficient pressure, the ignition transformer is started and the gas valves (main and safety) areopened. The burner starts.The quantity of gas (m3/h) supplied with the ignition flame can be regulated by operating on the air dampercontrol servomotor (see N° 0002933220 from BGN 40LX to BGN 390LX) (see N° 0002933490 for BGN 540LX).Note: The ignition flame has a higher gas flow rate than the minimum modulation flow rate.The flame is thus present and, detected by its control device, it allows continuing and ending the ignition step bydisabling the ignition transformer. The quantity of gas supplied with the high flame must be regulated by operating onthe air damper control servomotor (see dr. n° 0002933220 - 0002933490).In case of absence of ignition flame, the control box stops in “safety lock”. In case of “safety lock” the valves are closedimmediately. To unlock the control box from the safety position, press the luminous button on the control box.Note: For the gas valve regulation, see the specific instructions in the following pages. The air damper is actuated bya special electrical motor (see specific instructions in the following pages), note that as the burner is shut down by thethermostat enable, the air damper is restored to the total closure position by the control motor.DESCRIPTION OF THE MODULATION OPERATIONWhen the burner is on at the minimum flow rate, if the modulation sensor allows it (adjusted to a higher pressure ortemperature value than that in the boiler), the air regulation servomotor start running, thus determining a gradualincrease of the combustion air supply, and consequently, of gas, until the maximum supply at which the burner isregulated is reached. The air pressure increase in the ventilator is detected by the gas valve sensor, model MB-VEF..or DMV-VEF.., which gradually adjusts the gas supply to the also gradual air pressure variation.The burner remains in the maximum supply position until the temperature or pressure reaches a sufficient valve todetermine the intervention of the modulation sensor, which makes the air regulation servomotor run in the reversedirection with respect to the previous one. The backward rotation and the air and gas supply reduction occur at shorttime intervals. With this operation, the modulation system attempts to balance the quantity of heat supplied to the boilerwith that yielded by the same during use. The modulation probe applied to the boiler detects the request variations andautomatically provides to adjusting the fuel and the combustion air supply by enabling the air regulation servomotorwith increasing or decreasing rotation. If the limit value (temperature or pressure) is reached also with minimum supplyto which the total shut down device is set (thermostat or pressure switch), the burner is shut down by the interventionof the same. As the temperature or pressure fall below the shut down device enable value, the burner is started againaccording to the previously described program. If the flame does not appear, the control box “locks” (total burner shutdown and lighting of the relevant warning light). To “unlock” the control box, press the special push button.COMBUSTION CONTROLFor a correct air/gas ratio, the methane carbon dioxide (CO 2 ) value must be at least 8% at the minimum burner supply,up to an optimum value of 10% for maximum supply. It is advisable not to exceed a 10% value so as to preventoperation with too limited air excess, which could cause (atmospheric pressure variation, presence of dust in the airducts) a sensible CO (carbon oxide) quantity. To prevent dangerous situations, the carbon oxide (CO) percent-age in the flue gas must always measured with the special instrument to make sure that it does not exceed themaximum admissible value of 0.1%.