1
2
– Turn off and turn on the boiler a few
times whilst keeping the hot water cock
constantly open to verify that the pressu-
re corresponds to the values given in
Table 4.
After having regulated the maximum pres-
sure, proceed with the setting of the mini-
mum pressure (fig. 25):
– Disconnect the electric supply of the
modulator.
– With the D.H.W. potentiometer knob on
the maximum value, the hot water cock
open and the burner alight, holding the
nut (3) blocked, turn the screw (2) to find
the minimum pressure value as shown in
Table 4: to decrease the pressure turn
the nut anti-clockwise and to increase
the pressure turn the nut clockwise.
– Turn on and turn off the boiler a few
times whilst keeping the hot water cock
constantly open and verify that the pres-
sure corresponds to the values fixed.
– Reconnect the electrical supply of the
modulator.
– Replace the plastic cap (1).
4.2.2
Maximum and minimum
pressure adjustment
HONEYWELL VK 8105N
For the setting of the minimum pressure
proceed in the following way (fig. 25/a):
– Connect the differential manometer as
shown in fig. 24/b.
– Remove the plastic cap of the modula-
tor (1).
– Place the D.H.W. potentiometer knob on
the maximum value.
– Start the boiler and open the hot water
cock.
– Using a 9 wrench turn the nut (3) to find
the maximum pressure as shown in
Table 4: to reduce the pressure turn the
nut anti-clockwise, to increase the pres-
sure turn the nut clockwise.
– Turn off and turn on the boiler a few
times whilst keeping the hot water cock
constantly open to verify that the pressu-
re corresponds to the values given in
Table 4.
3
KEY
1 Plastic cap
2 Minimum pressure
adjusting screws
3 Maximum pressure
adjusting nut
After having set the maximum pressure,
for the setting of the minimum pressure
proceed in the following way (fig. 25/a):
– Disconnect the electricity of the modula-
tor.
– With the D.H.W. potentiometer knob on
the maximum value, the hot water cock
open and the burner alight, using a 7
wrench turn the nut (2) to find the mini-
mum pressure value as shown in Table
4: to decrease the pressure turn the nut
anti-clockwise and to increase the pres-
sure turn the nut clockwise.
– Turn on and turn off the burner a few
times whilst keeping the hot water
cock constantly open and verify that
t he pr essur e corr esponds t o t he
values of Table 4.
– Reconnect the electric supply of the
modulator.
– Replace the plastic cap (1).
4.3
REGULATION OF HEATING POWER
To regulate the heating power, modifying
Pressure/heat output diagram for natural gas (methane)
12
11
10
9
8
7
6
5
4
3
2
1
8, 1 (7.000) 11,6 (10.000)
Fig. 25
KEY
1 Plastic cap
2 Minimum pressure
adjusting nut
3 Maximum pressure
adjusting nut
the factory settings whose power value is
around 16 kW, it is necessary to work with
a screwdriver on the trimmer of the hea-
ting power (10, fig. 21).
To increase the operating pressure turn
the trimmer in a clockwise direction, to
decrease the pressure turn the trimmer in
an anti-clockwise direction.
To facilitate the search for the adjusting of
the heat output see the pressure/heat out-
put diagrams for natural gas (methane)
and butane or propane gas are available
(fig. 26).
25
17,4 (15.000)
23,2 (20.000)
HEAT OUTPUT kW (kcal/h)
POTENZA TERMICA kW (kcal/h)
Fig. 25/a
30
29,0 (25.000)
Fig. 26/a
101