Technical information

The blocking will only be discontinued when
the pressure exceeds 1.3 bar. This offers
the possibility to read the pressure in the
appliance during topping up.
0.2 bar < P < 0.5 bar
The capacity of the appliance is limited to
low load so that the user can still obtain
heat, but because of a reduced level of
comfort will realize that something is not in
order. In the status display, the letter
indicating the condition of the appliance
(rest, central heating use or hot water
operation) will alternate with ‘P’. The
temperature display will show the system
pressure. This condition will be discontinued
as soon as the pressure exceeds 1.3 bar.
P > 0.5 bar
The appliance will function without
limitations
P > 3.5 bar
All heating demand will be blocked and the
pump will be switched off. This blocking will
only be discontinued when the pressure
falls below 3.0 bar. The pressure can be
read from the display.
26.5 Air supply monitoring
The speed of the fan is measured and
monitored. If this varies by more than 5
percent from the correct speed for a period
of more than 60 seconds, the control
system will be blocked and a flashing ‘5’ will
appear in the status display. This indicates
that there is a problem with the air supply to
the appliance or with the fan.
26.6 Exhaust gas sensor (optional)
The appliance can be fitted in the factory
with an optional exhaust gas sensor that is
connected to the control system. This
exhaust gas sensor switches the appliance
off if the exhaust gasses reach too high a
temperature.
The following situations are possible:
T
exhaust gas
<80 °C
The appliance will function without
limitations
80 °C < T
exhaust gas
< 90 °C
The appliance functions normally but the
capacity will be limited to low load. On the
status display the normal status will be
replaced by ‘A’.
The temperature display will show the
supply temperature.
This condition will only be discontinued
when the exhaust gas temperature falls
below 60 °C.
90 °C < T
exhaust gas
< 95 °C
The control system locks-out all heating
demand.
The status display shows the letter ‘A’
continuously. The temperature display
shows the exhaust gas temperature. This
blocking will only be discontinued when the
exhaust gas temperature falls below 70 °C.
T
exhaust gas
> 95 °C
The control system locks-out operation, the
status display shows a flashing ‘A’.
The temperature display shows the current
exhaust gas temperature and the appliance
will require manually resetting.
26.7 Display
For normal burner operation the central
heating water temperature or the water
pressure will be displayed on the 2-
character display.
The status of the burner is shown on the
status display. After the ‘-’ pushbutton
(down) has been pressed, the version
number of the software will be displayed.
Example : U 21 means software version
055_21.
EC 25 Compact Installation/User Manual page
41