Technical data

30
Linea 24 & 28
8.23 Setting Gas Pressures
ALL SETTINGS DONE WITH A SUITABLE
MANOMETER CONNECTED TO GAS
VALVE AS INSTRUCTED IN 6.6.5
8.23.1 Setting Maximum Rate
Turn off electrical supply to boiler and follow
instructions in section 8.4 to gain access.
Refer to Fig. 23 & 37.
Turn on the electricity supply and the appli-
ance mode selector switch to Remove gas
pressure adjustment protective cover (fig. 37).
Turn on fully a domestic draw off tap.
The boiler will now light at full flame. Screw the
outer nut (a) on the end of the modulator coil
slowly clockwise until the burner lights.
Adjust the nut until the correct pressure is
obtained on the gauge. The correct reading
should be:
24 (N/G)
10.1 mbar.
plus or minus 1.0 mbar.
28 (N/G)
10.1 mbar.
plus or minus 1.0 mbar.
8.23.2 Setting Minimum Rate (DHW)
Remove one of the grey wires connecting to
the modulator coil. The gas pressure will now
be at the minimum rate.
Turn the inner minimum adjusting screw (b)
anti clockwise to decrease the pressure, or
clockwise to increase the pressure until the
minimum gas pressure is achieved, (ensure
when adjusting the inner screw the outer nut
(a) is held in position) the correct reading
should be:
24 (N/G)
1.5 mbar.
plus or minus 0.15 mbar.
28 (N/G)
1.3 mbar.
plus or minus 0.13 mbar.
Replace the grey wire back onto the modula-
tor coil together with the protective cover.
8.23.3 Setting Minimum Rate (C/H)
Turn off the hot water draw off tap.
Gain access to the electrical terminal blocks
(5.7.2). Fig.19.
Identify jumper plug position JP9 on circuit
board fig. 38 and fit a temporary jumper tag.
Turn the mode selector switch to the
position, ensure that the room thermostat
and/or timeclock (if fitted) are calling for heat.
Turn the heating thermostat to maximum and
ensure the appliance ignites.
Identify minimum adjustment button on pcb
(fig. 38).
Press the minimum adjustment button once,
the boiler will operate in central heating mode
at a minimum gas pressure. An LED on the
PCB will flash red to confirm the appliance is
in central heating minimum mode.
The gas pressure should now be:
24 (N/G)
1.9 mbar.
plus or minus 0.19 mbar.
28 (N/G)
1.6 mbar.
plus or minus 0.16 mbar.
If the reading is incorrect it should be adjusted
as follows:
Identify the minimum adjustment
potentiometer on the PCB fig. 38. With the
boiler still in central heating mode and the
burner at the minimum rate, using a small
screwdriver turn the potentiometer clockwise
to increase & anti-clockwise to decrease the
minimum gas pressure.
When all is adjusted, press the minimum
adjustment button once (the appliance will
return to normal operation). Turn the appli-
ance off and remove the temporary jumper
connected to plug JP9.
Fig. 37
Gas pressure adjustment
protective cover
Maximum pressure
adjustment screw (a)
Minimum pressure ad-
justment screw (b)