Baxi Luna 3 Comfort, Installers And Users Instructions

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61
926.427.1 - GB inStructionS Pertaining to the inStaller
B) change the modulator voltage
• setting
F02
parameter according to the gas used as described in section 20.
c) pressure adjusting device setting
• connect the positive pressure test point of a differential (possibly water-operated) manometer to the gas valve pressure
test point (
pb
) (Figure 13); connect, for sealed chamber models only, the negative pressure test point of the manometer
to a
“t”
fitting in order to join the boiler adjusting outlet, the gas valve adjusting outlet (
pc
) and the manometer. (The
same measurement can be carried out by connecting the manometer to the pressure test point ( pb ) after removing the
sealed chamber front panel);
If you measure the pressure of burners in a different way you may obtain an altered result in that the low pressure created
in the sealed chamber by the fan would not be taken into account.
c1) adjustment to nominal heat output
• open the gas tap;
• press
button (figure 1) and set the boiler in winter mode;
• open a hot water tap to reach a minimum
10 l/min
flow rate or ensure that maximum heating requirements are set;
• remove the modulator cover;
• adjust the tube brass screw (
a ) figure 14 to obtain the pressure settings shown in table 1;
• check that boiler feeding dynamic pressure, as measured at the inlet gas valve pressure test point ( pa ) (figure 13) is
correct ( 37 mbar for propane gas G.31 , 20 mbar for natural gas G20 );
c2) adjustment to reduced heat output
• disconnect the modulator feeding cable and unscrew the ( b ) figure 14 screw to reach the pressure setting corresponding
to reduced heat output (see table 1);
• connect the cable again;
• fit the modulator cover and seal.
c3) Final checks
• apply the additional dataplate, specifying the type of gas and settings applied.
Figure 13
sit gas valve mod. siGMa 845 honeywell gas valve mod. vK 4105 M
0904_0701
table of burner pressures
250 Fi 310 Fi
Gas used
G20 G31 G20 G31
injector diameter (mm) 1,18 0,74 1,28 0,77
Burner pressure (mbar*) 1,9 4,9 1,8 4,9
table 1
reDuceD heat output
Burner pressure (mbar*) 11,3 29,4 13,0 35,5
nominal heat outPut
no. of injectors 15
* 1 mbar = 10,197 mm H
2
O
250 Fi 310 Fi
Gas consumption at 15 °c - 1013 mbar G20 G31 G20 G31
Nominal heat output 2,84 m 3 /h 2,09 kg/h 3,52 m 3 /h 2,59 kg/h
table 2
reduced heat output 1,12 m 3 /h 0,82 kg/h 1,26 m 3 /h 0,92 kg/h
p.c.i. 34,02 MJ/m
3
46,3 MJ/kg 34,02 MJ/m
3
46,3 MJ/kg