32
IT
GB
FR
BE
DE
4.1
GAS VALVE (fig.9)
The
‘EKO OF’
boilers have HONEYWELL
VR 4601 and VRB 25PA gas valve with
a coil assembly which permits, through a
double-contact regulating thermostat, a
reduction in output corresponding to
approx. 75% (G20) and 85% (G31) of
nominal output before the burner goes
out completely.
The operating pressures is calibrated by
SIME in the factory.
Consequently these operating pressures
should not be altered.
Only when you switch to another type of
gas is it permitted to alter the operating
pressures (Table 1).
This operation should be carried out
exclusively by authorized technical
staff, or the guarantee will be nullified.
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 pressure and then the
minimum.
4
INSTRUCTIONS FOR USE AND MAINTENANCE
9
1
4
3
7
8
2
KEY
1
Coil EV1
2
Pressure regulator
3
Coil assembly
4
Coil EV2
7
Pressure inlet upstream
8
Pressure inlet downstream
9
Gas pressure switch of
minimum rate ( a knob with
a range between 5 to 40
mbar)
Fig. 9
40
30
20
10
0
500
1000
Portata l/h
∆
p mbar
50
60
0
70
80
100
1500
2000
2500
3000
3500
4000
5000
5500
4500
120
140
160
7 OF
9 OF
12 OF
6000
10 OF
11 OF
8 OF
Fig. 8/a
40
30
20
10
0
500
1000
Portata l/h
∆
p mbar
50
60
0
70
80
90
1500
2000
2500
3000
3500
4000
4500
100
3 OF
4 OF
5 OF 6 OF
“EKO 3/6 OF”
“EKO 7/12 OF”
HONEYWELL VR 4601
HONEYWELL VRB 25PA
(“EKO 3/7 OF - 3/4 OF PVA”)
(“EKO 8/12 OF”)
Flow rate l/h
Flow rate l/h
