OPERATION DESCRIPTION
TBG 85 P-V burner work in progressive two stage operation, and
therefore can work at two stages of power, the gas train provided
is composed of an ON/OFF type safety valve and a single stage
slow opening main valve.
Adjusting the air flow rate in relation to each stage is performed
using the combined actions of the air shutter activated by the
servomotor (1) and the inverter (2) which drives the rotation speed
of the electric motor hence varying the air flow produced by the fan.
The gas flow adjustment in the first and second stage is carried
out by a streamlined valve (3) whose movement is caused by the
rotation of the servomotor (1) through the lever and return system (4).
The inverter allows the programming of three rotation speeds for
the electric motor:
Vs rotation speed in relation to the ignition stage
V1 rotation speed in relation to the first stage of power
V2 rotation speed in relation to the second stage of power
To adjust the V1, Vs, V2 speeds consult chapter: "FREQUENCY
CONVERTER".
When the switch (1) is closed, if the thermostats are closed, the
voltage reaches the command and control equipment which starts
the boiler (LED 2 on).
This turns on the fan motor for preventilation (LED 3) of the
combustion chamber. During the preventilation phase the motor
goes at the maximum speed.
At the same time, the rotation of the servomotor (1) puts the air
shutter into the open position corrisponding to the second flame,
as a result the preventilation phase comes only with the air shutter
in the second flame position.
At the end of the preventilation phase, the air shutter and the gas
throttle are returned to the position set for the first flame. Meanwhile
the inverter turns the motor at the Vs speed programmed for the
ignition stage. The ignition transformer will cut in (LED 4) and, after
two seconds, the gas valves open (LED 5).
The presence of the flame, detected by the control device, permits
continuation and completion of ignition, turning off the ignition
transformer.
Subsequently, according to the heat requested by the system,
the burner continues to operate in first stage with the motor at V1
speed otherwise it passes to the second stage of power (LED 6)
by the progressive opening of the air shutter and the gas throttle
simultaneously. During operation in second stage the motor goes
to rotation speed V2.
At the moment in which the demand for heat from the system is
satisfied, the boiler thermostat will intervene and shut down the
boiler. The air shutter through the rotation of the servomotor will
reach the closed position when inactive.
In the event that the control device does not detect the presence
of a flame, the control box activates a "safety shut down" (LED 7)
within 3 seconds of the opening of the main gas valve. In "safety
lock-out" mode the valves are closed again immediately. To release
the appliance from safety lock-out mode, press the lockout reset
button (8) on the schematic panel.
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