Unical DUA plus - Adjusting the Burner

24
Adjustment info
2.6 - ADJUSTING THE
BURNER
All the instructions below are for the
exclusive use of qualified technicians.
All the boilers leave the factory adjusted
and tested.
If it is necessary to change the adjustment
due to changes in the gas or adaptation to
the supply network conditions, it will be also
necessary to re-adjust the gas valve.
Attention: during this re-adjustment do
not draw any Domestic Hot Water.
For this reason it’s necessary to know the
boiler operation in service mode.
In order to activate this function, push and
keep hold the service push button, on the
control panel, for 3 seconds: the service
mode green led will be continuously . lighted
( continuous) and the boiler will
operate at the maximum capacity. Then
push once again the same button: the
service mode green led will start blinking
( blinking) . The service mode function
remains active for 15 minutes.
For cleaning this function before this fixed
period, push the reset button: the service
mode led will switched off ( off). .
To correctly adjust the gas valve, follow the
steps below:
A) Maximum output adjustment
- check the value of the supply pressure
(see table NOZZLES - PRESSURES);
- Remove the cover (A) protecting the
pressure regulator on the top of the
modulating coil.
- Connect a manometer at the outlet gas
valve pressure nipple.
- Activate the service mode function to
the maximum capacity (service mode led
continuous lighted).
- When the burner is ON, check that the
“MAXIMUM” pressure value corresponds
to that indicated on the table “NOZZLES -
PRESSURES”:
- Adjust, eventually, the value by keeping
locked the ‘’B’’ nut with a 5 mm open
wrench and rotating the “C” nut with a 8
mm open wrench (fig. 27) by clockwise
rotation the gas pressure increases, by
anticlockwise rotation the gas pressure
decreases.
B) Minimum output adjustment
- Operate the boiler in service mode at
minimum output (service mode led
blinking).
- When the burner is ON, check that the
“MINIMUM” pressure value corresponds
to that shown on the table “NOZZLES
PRESSURES”:
- Adjust, eventually, the value by keeping
locked the ‘’C’’ nut with a 8 mm open
wrench and rotating the “A” nut with a 5
mm open wrench (fig. 27) by clockwise
rotation the gas pressure increases, by
anticlockwise rotation the gas pressure
decreases.
fig. 27
A
Perform the
adjustments by
keeping lock the
position of the
‘’B’’ or ‘’C’’ nut
(depending on
the type of
adjustment) in
order to avoid
misadjustments.
C) Ending of basic adjustments
- check the min. and max. pressure values
of the gas valve by acting the service
mode
- if necessary make any fine adjustments
- Clear the service mode function by
pushing the reset button or switching off.
- Remove the plastic pipe from pressure
test nipple and close the inner screw;
- Use soap solution tocheck for gas
leaks.
Position of the soft ignition adjuster for all
the situations. Plug for the soft ignition
adjuster
Plug for the soft
ignition adjuster
fig. 26
MP = pressure test nipple
MP
PRESSURE TEST NIPPLE
OPERATION AT THE
MAXIMUM CAPACITY
MIN - MAX
OPERATION AT THE
MINIMUM CAPACITY
MIN - MAX
CHIMNEYSWEEPER
DE ACTIVATION
(BEFORE 15 MIN)
MIN - MAX
MODULATING COIL
GAS VALVE
Outlet
pressure
test
nipple
Inlet
pressure
test nipple
B = Minimum
pressure
adjust. screw
(red)
(wrench 5 mm)
C = Maximum
pressure
adjust. nut
(wrench 8 mm)