Alpha InTec² 25XE and 28XE
3
Alpha E-Tec Plus 28 and 33
The temperature of the hot w
ater to the taps can be adjusted by using the hot w
ater temperature control b
uttons
(items 4 and 5 in Fig. 1) to the required v
alue shown on the displa
y in °C.
When a tap is opened the display will indicate the temper
ature of water in the boiler heating the tap w
ater and not
the actual water temper
ature to the tap.
Attention: W
ater at a temperature g
reater than 50°C can cause serious b
urns
. Alw
ays chec
k the water temper
ature before use
.
The temperature of the centr
al heating water can be adjusted b
y using the heating temperature control b
uttons (items 6 and
7 in Fig. 1).
When the heating is on the temper
ature of the water lea
ving the boiler to the radiators will be displa
yed.
If an exter
nal weather compensation probe is fitted, indicated b
y the
symbol (item 12 in Fig. 1) in the displa
y, it will
automatically var
y the temperature of the w
ater in the radiators and on a mild da
y the radiators will not f
eel as hot as on a
cold day, this is nor
mal and not a fault with the boiler or heating circuit.
The room temper
ature will still be maintained as set
by the room ther
mostat.
When an exter
nal weather sensor is fitted, the centr
al heating temperature control b
uttons (items 6 and 7 in Fig. 1) will no
longer adjust the flow temper
ature in °C, instead the displa
y 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 giv
e a flow temper
ature of 60°C when the exter
nal temperature is 10°C
.
Note: This is the temper
ature of the water supplied to the r
adiators and not the desired room temperature
. The time and
temperature will still be maintained according to the setting of the room ther
mostat.
3
HEATING AND HO
T W
ATER
TEMPERATURE
Fig. 2 - External weather compensation pr
obe 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
The system pressure when cold should be 1 bar i.e. within the g
reen section of the pressure gauge.
E-T ec Plus models ha
ve an integ
rated filling loop under
neath the boiler combined with the isolation valv
es. It ma
y
be necessary to remo
ve the co
ver under the boiler to e
xpose the filling loop.
Check the loop is fully connected b
y the sliding brass section betw
een the cold mains inlet and the left primar
y return
tightening to seal. Carefully open the b
lack tap on the r
ight return connection, no
w slowly open the left b
lack tap and the
system will begin to fill.
Observe the reading on the pressure gauge and close the tap when the pointer is in the upper g
reen section just above 1 bar
.
It is normal f
or the pressure to rise abo
ve the g
reen section when the heating is on as the system expands
.
If the system is overfilled and the pressure is g
reater than the green section when cold the pressure can be reduced b
y
carefully venting some w
ater from a radiator
.
The filling loop can be seen in the Installation instructions Fig.
5.4 in this manual.