Beretta Mynute LOW NOx 24 C.S.I. Installer And User Manual page 7

- power the boiler setting the system main switch to "on"
- check that the pressure on the pressure gauge is stable; or with
a milliammeter in series to the modulator, make sure that the
modulator supplies the maximum available current (120 mA for
G20 and 165 mA for LPG).
- carefully prise out the protection cap of the adjustment screws,
using a screwdriver (fig. 21)
- with a fork spanner CH10 use the adjustment nut of the maxi-
mum output in order to obtain the value indicated in table "Tech-
nical data"
- disconnect the modulator faston
- wait until the pressure on the pressure gauge is stable at mini-
mum value
- paying attention not to press the internal shaft, use an Allen
spanner to turn the red adjustment screw for domestic hot water
minimum temperature regulation, calibrating it until the pressure
gauge reads the value indicated in the table "Technical data"
- reconnect the modulator faston
- close the domestic hot water tap
- carefully refit the protection cap of the adjustment screws.
4.5.2 Minimum and maximum heating electric adjust-
ment
The "electric adjustment" function is activated and deactivat-
ed exclusively by the jumper (JP1) (fig. 22).
ADJ appears on the display to indicate that the calibration pro-
cedure is underway.
The function can be enabled in the following way:
- by powering the card with the jumper JP1 inserted and the mode
selector in winter position, independently from the possible pres-
ence of other operation request.
- by inserting the jumper JP1, with the mode selector in winter po-
sition, without heat request in progress.
By activating the function the burner is ignited through simu-
lation of heat request in heating.
To perform calibration operations, proceed as follow:
- switch off the boiler
- remove the shell and access the card
- insert the jumper JP1 (fig. 22) to enable the knobs placed on the
control panel to the minimum and maximum heating adjustment
functions.
- make sure that the mode selector is in winter position (see sec-
tion 4.2).
- power the boiler
Electric card in voltage (230 Volt)
- turn the heating water temperature adjustment knob B (fig. 23)
until it reaches the minimum heating value as indicated in the
multigas table
- insert the jumper JP2 (fig. 22)
- turn the domestic hot water temperature adjustment knob C (fig.
23) until it reaches the maximum heating value as indicated in
the multigas table
- remove the jumper JP2 to store the maximum heating value
- remove the jumper JP1 to store the heating minimum value and
to get out the calibration procedure
- reconnect the compensation inlet to the air distribution box
Disconnect the pressure gauge and retighten the pressure test
point screw.
To finish the calibration function without storing the set val-
ues, proceed as follows:
a) set the mode selector to position (OFF)
b) remove power supply voltage
c) remove JP1/JP2
The calibration function is automatically finished, without
storing minimum and maximum values, after 15 minutes of
its activation.
The function is automatically finished also in case of definitive
stop or lockout.
Also in this case, function conclusion DOES NOT provide val-
ues storing.
Note
To calibrate only maximum heating, it is possible to remove the
jumper JP2 (to store the maximum) and then get out from the func-
tion, without storing the minimum, setting the mode selector to
(OFF) or removing the voltage from the boiler.
After each intervention on the adjustment element of the gas
valve, seal it with sealing varnish.
When adjustment is complete:
- restore set temperature with the room thermostat to the desired
temperature
- set the heating water temperature selector to the desired position
- close the instrument panel
- pull the shell back in place.
4.6 Gas conversion operations
Conversion from a family gas to other family gas can be performed
easily also when the boiler is installed.
The boiler is designed to operate with methane gas (G20) accord-
ing to the product label.
It is possible to convert the boilers from one gas type to another by
using the appropriate kit supplied upon request:
- Methane conversion kit
- LPG conversion kit
For disassembly refer to instructions below:
- remove power supply from the boiler and close the gas tap
- remove the components to access to the internal parts of the
boiler: shell,air box cover, left side air box cover and combustion
chamber (fig. 25)
- disconnect the spark plug cable connection and the compensa-
tion pipe on the gas valve
- slide off the lower cable from the seat of the air distribution box
- loosen the nuts on the water inlet and outlet pipes from the burner
- remove the burner fixing screws and remove the latter with the
spark plug attached and corresponding cable
- using a socket or fork spanner, remove the nozzles and the
washers and replace them with the ones in the kit
- if the conversion is from methane gas to LPG, position the flange
contained in the kit on the manifod
- if the conversion is from LPG to natural gas, remove the flange
from the burner.
Use and assemble the washers contained in the kit also
in case of manifolds without washers.
- to position again the components carefully do the inverse opera-
tions
On the control board (fig. 22):
- if the conversion is from methane gas to LPG, insert the jumper
in position JP3
- if the conversion is from LPG to methane gas, remove the jumper
from position JP3
- reposition the components previously removed
- restore voltage to the boiler and reopen the gas tap (with boiler in
operation, check correct seal of the gas feeding circuit connections).
Conversion must be carried out by qualified personnel.
After conversion, adjust the boiler again following the indica-
tions in specific section and apply the new identification label
contained in the kit.
Check the tightness of the components previously removed
5 - MAINTENANCE
To ensure product characteristics and efficiency remain intact and
to comply with prescriptions of current regulations, it is necessary
to render the appliance to systematic checks at regular intervals.
Control frequency depends on the installation and use conditions,
but it is therefore necessary an annual check-up by the authorised
personnel from the Technical Assistance Service.
Turn off the appliance to carry out the maintenance of the structure
near the flue exhaust connections or devices, and their accesso-
ries. Once the interventions are finished a qualified technician must
check that the pipes and the devices work correctly.
IMPORTANT: before carrying out any cleaning or maintenance op-
eration of the appliance, use the appliance and system switch to
interrupt power supply and close the gas supply turning the tap
placed on the boiler.
Mynute LOW NOx C.S.I.
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