4
USE AND MAINTENANCE
4. 1
D.H.W. PRODUCTION
"25 BFT boiler - BT100 tank"
The preparation of hot water is guaranteed
by the glass storage tank unit with magne-
sium anode for the protection of the boiler
unit and inspection flange for its control and
cleaning.
The magnesium anode must be checked
annually and substituted when it is worn.
It is advisable to place a sluice gate at the
entrance of the D.H.W. tank unit which,
apart from the total closure, allows the
regulation of the supply capacity.
If the boiler does not produce hot water,
make sure that the air has been released
by pressing on the manual vents after hav-
ing switched off the main switch.
4.2
ADJUSTMENT OF
D.H.W. FLOW RATE
To adjust the hot water flow rate, use the
flow-rate regulator on the pressure switch
valve (7 fig. 5).
Remember that the flow rates and corre-
sponding temperatures of use of hot water,
given in section 1.3, have been obtained by
positioning the selector of the circulation
pump on the maximum value.
Should there be any reduction in the D.H.W.
flow rate, the filter installed on the inlet to
the pressure switch valve (3 fig. 5) will need
cleaning.
This may be accessed only after closing the
cold water on/off cock on the fixing
4.3
GAS VALVE
The boiler, is equipped standard with the
HONEYWELL VK8105N gas valve (fig. 28)
set at two pressure values: maximum and
minimum.
According to the type of gas burnt, these
correspond to the values given in Table 5.
The gas pressures at the maximum and
KEY
1
Modulator
2
EV1-EV2 coils
3
Pressure inlet upstream
4
Pressure inlet downstream
5
VENT plug
TABLA 5
Type of gas
Methane - G20
Butane - G30
Propane - G31
minimum values, are factory set.
Consequently they must not be altered.
Only when you switch the appliance from
one type of gas supply (methane) to another
(butane or propane), it is permitted to alter
the operating pressure.
It is essential that this operation is car-
ried out exclusively by authorized techni-
jig.
cal staff.
When the working pressures have been
adjusted, reseal the regulators. When the
gas pressures are to be reset, this must be
done following a set order: first the MINI-
MUM and then the MAXIMUM.
4.3. 1
Minimum and maximum
pressure adjustment
To set the minimum pressure, proceed as
follows (fig. 29):
– Connect the pressure column or a pres-
sure gauge to the pressure inlet down-
stream of the gas valve. In the "30 BF"
versions, instead, connect the manome-
ter as shown in fig. 28/a.
– Disconnect the electric power and remo-
ve the plastic cap on the modulator (1).
– Set the knob of the D.H.W. potentiome-
ter to the maximum value.
– Ignite the boiler by operating the swit-
ch and open the D.H.W. tap at a high
flow rate.
– Using a ø 9 spanner, turn the nut (2) to
achieve the minimum pressure value
given in Table 5: to reduce the pressure,
turn the nut counterclockwise; to increa-
se the pressure, turn it clockwise.
– Operate the main switch a number of
times, keeping the D.H.W. tap open all
Fig. 28
the time, and check that the pressure
corresponds to the values given in
SEALED CHAMBER
PRESSURE INLET UPSTREAM
VENT PLUG
Burner max.
Modulator
pressure
current
mbar
mA
9 - 11
130
27 - 28
165
35
165
– Restore electric power to the modulator.
After having adjusted the minimum pressu-
re, calibrate the maximum pressure as fol-
lows:
– With the domestic hot water potentio-
– Operate the main switch a number of
MANOMETER
Fig. 28/a
Burner min.
Modulator
pressure
current
mbar
mA
2
5
5 - 7
Table 5.
met er knob on t he maximum, t he
domestic hot water tap open and the
burner ignited, using a ø 7 spanner
turn the nut (3) to get the maximum
pressure value given in Table 5: to
reduce the pressure, turn the nut
counterclockwise; to increase the pres-
sure, turn it clockwise.
times, keeping the D.H.W. tap open all
the time, and check that the pressure
corresponds to the values given in
Table 5.
KEY
1 Plastic cap
2 Minimum pressure adjusting nut
3 Maximum pressure adjusting nut
4 Modulator
0
0
0
Fig. 29
121