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ADJUSTING THE GAP BETWEEN DISC AND NOZZLE
The burners are fitted with a device that allows the gap between the disc and the nozzle to be adjusted.
The gap between the disc and the nozzle is factory set, and must only be reduced if the cone of atomised fuel at
the nozzle outlet wets the disc, resulting in fouling.
UV PHOTOCELL
Even slight oiliness greatly affects the passage of UV rays to the bulb in the UV photocell, preventing the sensitive
internal element from receiving the amount of radiation required for the unit to work properly. If the bulb is dirtied
by gas oil, fuel oil, etc., it must be cleaned properly. Even touching the bulb with a finger can leave enough oiliness
to affect operation of the UV photocell. The UV cell does not “see” daylight or light from a normal lamp.
Its sensitivity can be checked using a flame (lighter, candle) or an electric spark between the electrodes of a
simple ignition transformer. To ensure that the unit works properly, the current on the UV cell must be sufficiently
stable and must not fall below the minimum value required for the specific equipment.
The best position may have to be found by experimenting, by sliding (axial movement or rotation) the body
containing the photocell on the clamping bracket. The unit can be checked by connecting a micro-ammeter, with
a suitable scale, in series with one of the two UV photocell cables. Obviously the polarity must be respected
( + and - ). The current value required for the cell to ensure unit operation is given in the wiring diagram.
Check the efficiency of the flame detector (UV photocell). The photocell is used to monitor the flame and must
therefore be able to intervene if the flame goes out while the system is working (this check must be carried out at
least one minute after ignition). The burner must be able to shut down (cut-out) and remain off if the flame does
not appear regularly during ignition, within the time allowed by the control unit. Cut-out leads to the fuel being shut
off immediately, the burner is stopped and the block LED comes on. To check the efficiency of the UV photocell
and the cut-out device, proceed as follows:
a) Start the burner
b) A few minutes after ignition remove the photocell from its seat, thereby simulating the absence of the flame.
The flame on the burner must go out and the unit must “cut-out”.
c) The unit can only be reset manually by pressing the special reset button. The cut-out efficiency check must be
carried out at least twice.
Check the efficiency of boiler thermostats or pressure (their intervention must stop the burner).
VARIATION FOR BURNERS FITTED WITH A FUEL OIL STEAM PRE-HEATER
The burner can be fitted with a steam fuel oil pre-heater to heat the fuel, thereby saving electricity.
This device comprises a small tank in which the steam circulates. The tank contains a coil through which the fuel
oil to be heated circulates. This allows a considerable reduction in the size of the pre-heater.
On burner ignition, the cold fuel oil is forced to pass through the coil of the steam pre-heater which is still cold
since is it still not fed with steam. The high viscosity of the (cold) fuel, the considerable length of the coil and its
relatively small diameter (necessary for a high heat exchange) would cause a big loss of pressure, resulting in the
fuel reaching the nozzle at an insufficient pressure. To avoid this situation the steam pre-heater is fitted with a
manual control by-pass gate valve which, when opened, allows the coil to be by-passed (see BT 8576).
INSTALLATION
The user must supply and fit a gate valve, a suitable pressure reducer (adjustable between 1 and 8 bar), and a
pressure gauge (full scale 10 bar), to the piping that delivers the steam to the fuel heater. Do not recycle the
condensate discharged by the heater, in order to avoid getting fuel oil in the steam system in case of leaks in the
coil.
