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LB1312
Oilflam 700.1-800.1 PR/MD
MODULATING OPERATION
With the bumer in the start position and the appliance thermostats enabled, power is delivered to the
resistances (G) of the preheater and heating cartridges for the pumps and the fuel supply line to the head
(O). When the preheater thermostat reaches the set value, (usually a minimum of about 90°C is necessary
to guarantee a good level of circulation) the pump start-up is enabled (set point on out 1, if using the
GEFRAN 200 thermoregulating device).
If the preheating system of the tank is also equipped for a fluid exchanger (hot water, steam, diathermic
oil) the thermostat may enable a contact in the terminal block for any stop-start of the fluid electrovalve.
This is not a standard solution as the heated fluid is normally always connected. The pump starts to send
oil (the head has already been heated by its cartridge (O) and therefore has no residue of cold dense oil)
which flows from the tank to the head and then to the return line of the ring.
When the head thermostat reaches the set value (usually about 70-30°C the cycle starts properly and the
control programmer enables start-up. The servomotor sets itself at minimum (see chapter on regulation)
acting on the air and fùel via the pressure regulator on the return.
The electromagnet (A) opens the nozzle (Q) in the followmg condition :
- sparks from the ignition electrodes are generated by the transformer also governed by the burner
control device.
If the cell fails to detect the flame the burner shuts down (with the cyclic control programmer cutting in).
Once ignition has taken place and after the flame stabilisation period, the system starts operating in
modulating mode.
- Before start-up make sure that the pump and delivery pipes are completely filled with hot fuel oil; the
absence of fuel oil can cause pump seizure.
- If there is a block, a specific waring light on the programmer and on the burner front control board
lights up and this signal is usually sent to the main control board of the equipment using the burner,
setting off a buzzer and warning light.
- A few blocks are normal on first starting up (up to about 4); to release press the button on the
programmer (also found on the front of the bumer control board) for repeating the start cycle. Should
they continue to occur seek the help of a specialised technician.
N.B. The position of the programmer at the time of the block is memorised to supply an indication of the
cause of this block.
OIL DELIVERY ADJUSTMENT
The diagram illustrates the fuel feeding system of these type of burners, which incorporates a by-pass nozzle
with oil flow regulation on its return pipe. The oil supply is varied by acting on the nozzle through the
pressure in the return line. Max. oil supply is therefore reached when the pressure in the pump line is about
30 bar and the return line is fully closed; min. oil supply when the return line is fully open(see also diagram
BERGONZO). Relevant pressure readings in the return line are as follows (return oil
pressure has to be measured on “M” pressure gauge):
Pump pressure 25-30 bar.
Max Burner output, return oil pressure:
FLUIDICS nozzle : 16 ÷19 bar.
BERGONZO nozzle : 20 ÷24 bar.
Min Burner output, return oil pressure:
FLUIDICS nozzle : 6 ÷9 bar
BERGONZO nozzle : 4 ÷8 bar
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