Alpha InTec2 20SE Installation And Servicing Instruction page 27

5.5 INITIAL LIGHTING - Refer to Fig. 5.1
1. Before turning on the gas and electrical supplies check the heating system is filled to the correct pressure. Refer to
Section 5.1 Fill the System. The pressure gauge on the right of the control panel indicates the heating system pressure.
When the boiler is cold the needle should be within the green band.
2. With the gas and electrical supplies to the boiler off, ensure that the mains water inlet valve and the central heating flow
and return valves are open.
3. Turn on the gas and electrical supplies to the boiler.
When the electricity supply is turned on, the boiler will automatically go through a system purging cycle for 8 minutes
counting down from 96 on the display. This can be interrupted by pressing the RESET button (item 3 in Fig. 5.1). It is
recommended that this cycle is allowed to complete when first lighting the boiler to help remove air from the system.
After this the boiler will be in either Standby or On mode, the On-Off/Standby button (item 1 in Fig. 5.1) is used to scroll
between these modes or press and hold it in to turn the boiler off.
Note: This does not isolate the electricity supply to the boiler.
4. Ensure all external controls are calling for heat.
If the optional controls are fitted, refer to the instructions supplied, and ensure they are in an 'on' mode.
5. Press the Summer/Winter button (item 2 in Fig. 5.1) to select either summer (
Note: The Summer mode will only function if the Alpha diverter kit has been fitted. When using a standard 'Y' or
'S' plan system the boiler MUST BE left in Winter mode.
Summer (
): In this mode the boiler will only fire when hot water is requested through opening a hot water outlet tap
and the heating will not function even if requested by any controls. The desired hot water temperature can be set using
the hot water selector switch (item 5 in Fig. 5.1) on the control panel, when the tap is open the display will indicate the
actual primary flow temperature (item 14 in Fig. 5.1).
Winter (
): In this mode the boiler will function in heating and hot water depending on the request from any controls
fitted. The boiler will always prioritise hot water when any hot outlet tap is opened. The heating will activate depending
on the request from any external controls fitted. The domestic hot water (item 5 in Fig. 5.1) and central heating (item
6 in Fig. 5.1) selector switches on the control panel can then be turned to the required set temperatures shown on the
display. The primary flow temperature will be displayed (item 14 in Fig. 5.1) when operating in heating or hot water.
Note: If a weather compensation sensor is fitted (can only be fitted when the Alpha diverter kit is fitted) a gradient value
of 1 to 9 is displayed (see Fig. 5.1) when adjusting the central heating temperature selector switch. This is because the
boiler output is modulated according to outside temperature. Refer to external sensor instructions for further information
on this feature and Section 4.11.
6. From this moment the boiler functions automatically. With no demand for heat (central heating or domestic hot water
production) the boiler goes to "standby" function.
Each time the burner ignites, the flame present symbol (item 10 in Fig. 5.1) is displayed together with the relative
strength of the flame (output power).
For any controls fitted please refer to the instructions supplied with the controls for connection and operation details and
Section 4.11.
5.6 BOILER OPERATION
Domestic hot water supply always takes priority over central heating. If a demand for hot water is required during a central
heating period, the boiler will automatically switch to the hot water mode until the demand is satisfied. This interruption in the
central heating is only when the demand for hot water is present and should not be noticed by the User.
Central heating mode
If there is a call for heat, the pump will start to circulate the central heating water. The fan will run and the premix burner will
light. The burner output then automatically adjusts to suit the system demand; as the temperature of the water in the boiler
approaches that set by the adjustable temperature thermostat, the burner output is reduced. When the set temperature is
reached, the burner is turned off. The fan continues to run for 30 seconds and the pump continues to run for three minutes, after
which the burner can relight if required. If the primary sensor has not registered the preset temperature but the room thermostat
is satisfied the burner is turned off. The fan continues to run for 30 seconds and the pump continues to run for 10 seconds. In
this instance there is no delay before the burner will relight.
Note: If the system pressure is very low, the primary pressure switch will prevent the boiler from operating.
The fan modulates according to the output required.
) or winter (
Alpha InTec² 20SE and 30SE - Commissioning
) mode.
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