Supplied By www.heating spares.co Tel. 0161 620 6677
21
DOMINA F 24 - 30 E
FERELLA F 24 - 30 MEL
MILOS AIR COMPACT E
Version - 09.2002
2.4 Burner unit
Operation
The burner unit comprises a manifold and 12/16 nozzles (depending on the capacity), the burner mount,
electrodes and the burner assembly.
Manifold - nozzles
The valve sends gas at a suitable pressure to the manifold, which
homogeneously distributes the gas to the single burner stages at the
nozzles. It is secured directly to the burner mount. Its positioning must be
exact since it affects the air/gas mixture. In addition, the threaded holes
forming the seat of the nozzles must be aligned with the respective Venturi
tube of the burner. If it were not so, the air/gas mixture would be wrong and
there would be poor combustion with an unstable flame. The nozzles are
made of brass and machined extremely precisely for their dimensions. There
is a seal between the nozzles and the manifold.
Ignition electrode
The ignition electrode is made of a metal alloy (Kanthal) that withstands high
temperatures and oxidation. Its base is composed of a ceramic composite
of glazed alumina whose purpose is to protect and electrically insulate it.
Once the ignition procedure begins, the card powers the electrode with a
pulsating voltage of a few kV, a series of electrical discharges is set off
between the electrode and the head of the burner (set at a distance of 3.5
mm). Clearly, these sparks are the trigger for the air-gas mixture. It is
important for the distance between the electrode and the burner head to be
3 - 4 mm and the discharge to be made at the centre.
Checks
If there is no discharge:
Check whether the boiler shuts down, in which case check
the connection of the electrode to the card or whether it
discharges at other points; if necessary, check the safety
thermostat and the card.
If the boiler does not shut down and the fan keeps on
working, check the air pressure switch.
If there is a discharge, but no ignition and after 10 seconds
the boiler shuts down, check the gas valve and, if necessary,
the card.
If there is a discharge and then a flame, but the boiler still
shuts down after 10 seconds, check the detection electrode
and its connection.
