The HT 1.450 is set to work with Gas A (Natural Gas) with a minimun gas supply pressure of 5.2 in w.c. (13.0 mbar). To
convert the unit to work with low gas pressure it is necessary to change the pcb settings as shown in table 2.
Gas supply pressure
mbar
in w.c.
12.0
11.0
10.0
9.0
Table 1.2
The HT 1.650 is set to work with Gas A (Natural Gas) with a minimun gas supply pressure of 15 mbar (6 in w.c.). To con-
vert the unit to work with low gas pressure it is necessary to change the pcb settings as shown in table 2.
Gas supply pressure
mbar
in w.c.
14.0
13.0
12.0
11.0
10.0
9.0
Table 1.2
CONVERSION FROM GAS A (NATURAL GAS) TO GAS E (LPG GAS)
WARNING
If the appliance is being converted from Gas A (Natural Gas) to Gas E (LPG Gas), the following operations must
be performed before calibrating the gas valve:
1 With the QAA73 controller, check and set parameters 608 and 611 (see section 12.5) at value of % and rpm indi-
cated in the table 2 and as explained in "fan speed adjustment" paraghraphs.
2 Turn adjuster screw (V) on the gas valve clockwise through the number of complete revolutions specified in table 2.
Clockwise
turns of screw
(V)
Gas A (Natural Gas)
3
Table 2
Clockwise
turns of screw
(V)
Gas A (Natural Gas)
5
Table 2
Then folllow calibration mode procedure as indicated on section 12.8.
INSTALLATION AND SERVICING INSTRUCTIONS
HT 1.450
CO
max. heat input
2
%
4.8
8.0
4.4
7.5
4.0
8.7
3.6
8.7
HT 1.650
CO
max. heat input
2
%
5.6
8.3
5.2
7.8
4.8
8.7
4.4
8.7
4.0
8.3
3.6
7.4
HT 1.450
Parameter 608
(%)
Gas E (LPG Gas)
25
25
HT 1.650
Parameter 608
(%)
Gas E (LPG Gas)
24
24
Fan speed
CO
min. heat input
(par. 536 and 613)
2
%
rpm
8.4
5,400
8.4
5,400
8.4
5,300
8.4
5,300
Fan speed
CO
min. heat input
(par. 536 and 613)
2
%
rpm
8.4
5,800
8.4
5,800
8.4
4,800
8.4
4,800
8.4
4,800
8.4
4,800
Parameter 611
(rpm)
Gas A (Natural Gas)
Gas E (LPG Gas)
2,100
Parameter 611
(rpm)
Gas A (Natural Gas)
Gas E (LPG Gas)
2,000
44
2,100
2,000
7110242.02 - en