Adjusting The; Gas; Sigma ) - Ariston microCombi 23 MFFI Installation And Servicing Instructions

4.2 A
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point of the gas valve "D".
Disconnect the compensation pipe "D1" either from the gas valve or from
the sealed chamber.
4. Push the On/Off button to "ON" position -green light- and ensure that the
hot water temperature control knob is set to maximum.
Turn on the boiler by running a hot water tap.
Adjust the 10mm nut "E" on the modureg to set the maximum gas
pressure, turn the nut clockwise to increase and anti clockwise to
decrease the pressure until the required pressure is achieved (see T
A page 30).
5. To set the minimum power, disconnect a supply terminal "F1" from the
modureg and adjust screw "F" (ensure that the 10mm nut is held in
position). Turn the screw clockwise to increase the pressure and anti-
clockwise
pressure gauge) corresponding to the minimum power (see T
30).
6. When you have completed the above operations, tur n off the
hot water tap, reconnect the supply ter minal to the modureg
on the gas valve, reconnect the compensation pipe and replace the cap
on the screw of the modureg.
Setting the maximum heating circuit power
D1
7. To set the maximum heating circuit power, push the On/Off button to the
"ON" position -green light- and push the Heating button and set the time
clock and any external controls to the "ON" position -green light. Turn the
knob of the heating thermostat clockwise to maximum.
8. Remove the inspection panel of the P.C.B. and fit a small cross-head
screwdriver in to the right hand potentiometer (see below). Turn clockwise
to increase the pressure or counter-clockwise to reduce the pressure.
Adjust the setting to the required heating pressure value (displayed on the
pressure gauge), as indicated in the charts shown on pages 30 and 31.
9. Turn off the boiler by placing the main switch to the "OFF" position.
Setting the pressure for soft-light ignition.
Disconnect the detection electrode connection close to the P.C.B. (F
2.13).
Start the boiler and during the ignition sequence adjust the left hand
potentiometer until the gas pressure reads the required gas pressure (see
the table on page 29).
Once the gas pressure is set turn off the boiler and re-connect the
detection electrode to the P.C.B.
NB.: It may be necessary to reset the flame failure reset a number of
E
times during this operation.
10. Remove the pipe from the test point and tighten the screw "C" to the
pressure test point in order to seal off the gas.
11. Carefully check the pressure test points for gas leaks (valve inlet and
outlet).
IMPORTANT!
Whenever you disassemble and reassemble the gas connections, always
check for leaks using a leak detection fluid.
F1
F
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to decrease the pressure (displayed
Soft-light Max Heating
Adjustment Adjustment
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on the
A page
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