14
Externa 30 O
Cod. 3540T540 - 04/2009 (Rev. 00)
Adjusting the maximum heating output
This adjustment may only be performed electronically using the adjustment potentiometer “P3”, star-
ting with a system temperature less than the maximum of the setting thermostat (system temperature
50 ¸ 60°C).
Connect a suitable pressure gauge to the pressure test point located downstream of the gas valve; turn
the temperature control knob to the maximum value, then adjust the pressure to the value required,
using the pressure-output diagram in the chapter on technical specifications. Once this operation has
been completed, turn the burner on and off 2 or 3 times using the thermostat and check that the pressure
remains stable at the set value. If not, a further fine adjustment must be performed, until the pressure
remains stable at the set value. When the burner is ignited to check the calibration pressure, turn the
setting thermostat knob to the maximum value, otherwise the procedure will be incorrect.
Adjusting the heating
¨
t by varying the flow-rate/discharge head of the pump
The thermal head,
¨
t (difference between the central heating outlet and inlet temperature) must be less
than 20°C. This is checked by varying the flow-rate and discharge head of the pump, using the speed
control (or switch) on the pump itself. Note that increasing the speed of the pump decreases the
¨
t,
and vice-versa.
3.2 Commissioning
The appliance must only be commissioned for use by Qualified Personnel, such as personnel from
our sales organisation or the local Customer Service Centre.
Checks to be performed during the first ignition, and after all maintenance operations which
may have required the disconnection from the systems or intervention on the safety devices or
parts of the boiler:
Before igniting the boiler:
• Open any on-off valves between the boiler and systems.
• Check the gas system for tightness, proceeding with care and using a soapy water solution to find
any leaks from the connections.
• Fill the system with water and ensure that the air contained in the boiler and the system has been
completely vented, by opening the air vent valve on the boiler and any vent valves in the system.
• Check that there are no water leaks in the heating system, in the domestic hot water circuits, in the
connections or in the boiler.
• Check the correct connection of the electrical system.
• Check that the appliance is properly earthed.
• Check that the pressure value and gas rate for the heating system are correct.
• Check that there are no inflammable liquids or materials in the immediate vicinity of the boiler.
Igniting the boiler
• Open the gas cock upstream of the boiler.
• Vent the air in the pipe upstream from the gas valve.
• Close any switches or insert any plugs upstream of the boiler
• Place the main switch in the ON position.
• Place knob “B” in the Winter position to a value higher than 50°C and set the room thermostat, if
fitted, to the required temperature value. At this point, the burner will ignite and the boiler will start
operating automatically, managed by its control and safety devices.
If, after correctly having performed the ignition operations, the burners do not ignite and the shut-
down warning light is on, wait around 15 seconds and then turn knob “A” (Fig. 1) to the RESET
position and release it. The control unit will be reset and will repeat the ignition cycle. If, after a
number of attempts, the burners do not ignite, refer to the paragraph “Troubleshooting”.
