Alpha InTec² 25XE and 28XE
The temperature of the hot water to the taps can be adjusted by using the hot water temperature control buttons (items 4 and
5 in Fig. 1) to the required value shown on the display in °C.
When a tap is opened the display will indicate the temperature of water in the boiler heating the tap water and not the actual
water temperature to the tap.
The temperature of the central heating water can be adjusted by using the heating temperature control buttons (items 6 and
7 in Fig. 1). When the heating is on the temperature of the water leaving the boiler to the radiators will be displayed.
If an external weather compensation probe is fitted, indicated by the
symbol (item 12 in Fig. 1) in the display, it will
automatically vary the temperature of the water in the radiators and on a mild day the radiators will not feel as hot as on a
cold day, this is normal and not a fault with the boiler or heating circuit. The room temperature will still be maintained as set
by the room thermostat.
When an external weather sensor is fitted, the central heating temperature control buttons (items 6 and 7 in Fig. 1) will no
longer adjust the flow temperature in °C, instead the display will show a scale of 1 to 9. Each number corresponds to a line
on the graph in Fig 2 i.e. line 6 will give a flow temperature of 60°C when the external temperature is 10°C.
Note: This is the temperature of the water supplied to the radiators and not the desired room temperature. The time and
temperature will still be maintained according to the setting of the room thermostat.
3 HEATING AND HOT WATER TEMPERATURE
Fig. 2 - External weather compensation probe fitted
Flow
temperature
(°C)
External temperature (°C)
27
15
5
-5
10
0
-10
-15
20
25 (25)
60 (40)
85 (50)
Flow temperature in brackets
ie. 25 to 50°C range when boiler
is used with a low temperature
system such as under floor heating
Setting 1 to 9 as selected using
the central heating selector switch
9
8
7
6
5
4
3
2
1
0
4 FILL AND PRESSURISE THE SYSTEM
E-Tec models should have a filling loop fitted by the installer located in the pipework below the boiler.
Do not attempt to fill or pressurise the system while the system is hot - wait for it to cool.
The filling loop will have a tap connection at either end.These taps should normally be in the closed position 90° to the tap
housing.
To fill or pressurise the system open one tap fully by turning it 90° anticlockwise in line with the tap housing. The second tap
should be opened a quarter of a turn and the water will start to refill the system (water should be heard filling the system).
You should see the pressure gauge (item 8 in Fig. 1) rise back up into the green area on the pressure gauge between 1 bar
and 1.5 bar pressure.
Once the pressure gauge is in the green area turn the taps back to the off position and the water will stop filling the system.
If you happen to fill the system too much and the pressure gauge needle is over the green area, just bleed water from a
radiator until the pressure on the gauge goes down into the green area.
It is normal for the pressure to be in the black area of the gauge when the boiler is operating
3
Alpha E-Tec 28 and 33
