4
USE AND MAINTENANCE
4. 1
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. 4).
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. 4) will need
cleaning.
This may be accessed only after closing the
cold water on/off cock on the fixing
4.2
GAS VALVE
The boiler, is equipped standard with the
HONEYWELL VK8105N gas valve (fig. 20)
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
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-
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 MAXIMUM and then the MINIMUM.
4.2. 1
Maximum and minimum
pressure adjustment (fig. 21)
To set the minimum pressure, proceed as
follows:
– Connect the pressure column or a pres-
sure gauge to the pressure inlet down-
stream of the gas valve. In the "30 BF"
SEALED CHAMBER
VENT PLUG
98
jig.
TABLE 5
Type of gas
Methane - G20
Butane - G30
Propane - G31
versions, instead, connect the manome-
ter as shown in fig. 20/a.
– Remove the plastic cap on the modula-
tor (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 9 spanner, turn the nut (3) to
achieve the maximum 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
the time, and check that the pressure
corresponds to the values given in
Table 5.
After having adjusted the maximum pres-
sure, calibrate the minimum pressure as
follows:
– Disconnect the electric power of the
MANOMETER
PRESSURE INLET UPSTREAM
Burner max.
Modulator
pressure (mbar)
current
25 BF
30 BF
mA
9,6
11, 1
130
27
26,8
165
35
34,9
165
modulator.
– With the domestic hot water potentio-
met er knob on t he maximum, t he
domestic hot water tap open and the
burner ignited, using a 7 spanner turn
the nut (2) to get the minimum pressu-
re value given in Table 5: to reduce the
pressure, turn the nut counterclockwi-
se; to increase the pressure, turn it
clockwise.
– Operate the main switch a number of
times, keeping the D.H.W. tap open all
the time, and check that the pressure
corresponds to the values given in
Table 5.
– Connect up the power supply to the
modulator again.
– Deplace the plastic cap (1).
Fig. 20/a
KEY
1
Modulator
2
EV1-EV2 coils
3
Pressure inlet upstream
4
Pressure inlet downstream
5
VENT plug
Fig. 20
Burner min.
Modulator
pressure (mbar)
current
25 BF
30 BF
mA
2
2,3
0
5
5,5
0
5
6,9
0
KEY
1 Plastic cap
2 Minimum pressure adjusting nut
3 Maximum pressure adjusting nut
Fig. 21