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26
7.2.6.1 HEATING PARAMETERS
When the boiler is operating in the SARA range,
the Green LED flashes rapidly to signify the
SARA function is active.
SARA FUNCTION
When the heating temperature selector is set
within the SARA range (SARA sector) the boiler
will automatically raise the heating flow outlet
temperature by 5 °C every 20-minutes that the
room thermostat contacts remain in the closed
position or until the boiler reaches the maximum
operating temperature.
7.3
CHECKING AND ADJUSTING BURNER
PRESSURE (see fig. 19)
Although the burner pressure is factory set, it is
necessary to check it during servicing or if the gas
valve has been removed.
Isolate the appliance from the electrical supply
and attach a suitable manometer to the gas valve
outlet test nipple.
RANGE
MINIMUM
MAXIMUM
Temperature (°C)
40
80
1
ST
sector
40
55
SARA sector
55
65
2
ND
sector
65
80
Fig. 39
7.3.1
SETTING THE MAXIMUM BURNER PRES-
SURE fig. 40
Light the boiler as described in 5.7 and compare
the reading on the manometer with the value
described in 2.3. If adjustment is required, re-
move the protective cap from the gas valve
modulating coil assembly and turn the outer
(10mm) nut clockwise to increase, or counter-
clockwise to decrease the burner pressure.
NOTE
Always check and/or adjust the minimum and
maximum gas pressures whilst the appliance is in
the HW only mode. Ensure a DHW outlet (pref-
erably the bath) is fully open, and that the HW
temperature selector is at maximum.
7.3.2
SETTING THE MIMIMUM BURNER PRES-
SURE fig. 39
Once the maximum burner pressure has been
checked and/or adjusted, remove one of the grey
wires from the modulating coil. Compare the
reading on the manometer with the value de-
scribed in 2.3. If adjustment is required, turn the
inner (red) crosshead screw clockwise to in-
crease, or counter-clockwise to decrease the
burner pressure, whilst ensuring that the outer
(10mm) nut does not move. When checking and/
or adjustment has been completed, isolate the
appliance from the electrical supply, replace the
protective cap, refit the grey wire to the modulat-
ing coil, remove the manometer and tighten the
outlet test nipple.
IMPORTANT, A GAS SOUNDNESS CHECK
MUST BE CARRIED OUT.
7.3.3
SETTING THE MINIMUM CENTRAL HEATING
OUTPUT
THIS CAN ONLY BE CARRIED OUT AFTER
THE MAXIMUM AND MINIMUM GAS PRES-
SURES HAVE BEEN SET.
●
Isolate the appliance from the electrical supply.
●
Attach a manometer to the gas valve outlet test
nipple.
●
Insert a jumper tag at JP2.
●
Switch the appliance ON in the heating mode.
●
Turn potentiometer P5 to the minimum position
●
Adjust potentiometer P4 to the required value
shown in section2.3 (section 10.2 for LPG), i.e.
minimum burner pressure (central heating).
●
Turn potentiometer P5 back to the maximum
position.
●
Isolate the appliance from the electrical supply.
●
Remove the manometer, tighten the outlet test
nipple, and check for soundness.
7.4
COMBUSTION ANALYSIS TEST
A combustion analysis check can easily be car-
ried out on the appliance via the test points
located on the top of the appliance, however you
must check that the burner pressures are set
correctly (see 7.3).
●
Isolate the appliance from the electrical supply
and turn the mode selector switch to the
OFF/
RESET
position.
●
Locate and remove the CO test point sealing
screw (see fig. 41).
●
Insert the flue gas analyser probe into the test
point.
●
Restore the electrical supply to the appliance
●
Remove the mode selector knob and turn the
shaft fully clockwise (see fig. 42).
Fig. 40
