GENERAL
16
- The DHW priority function. This ensures that the boiler
can still serve the central heating circuit even when
domestic hot water is drawn off.
- The frost protection function:
This stops water freezing inside the boiler. If boiler
temperature falls below 5°C, the burner ignites and
runs at full power until temperature reaches 10°C.
The frost protection function is only active if an outdoor
temperature sensor is connected. If outside tempe-
rature drops below -5°C the pumps are switched on.
If outside temperature is between -4° and 1.5°C, the
pumps are switched on for 10 minutes at intervals of
6 hours. If outside temperature is above 1.5°C the
pumps are switched off.
- Overtemperature dispersal function. If the temperature
threshold thermostat trips (86°C) the boiler shuts down
and accumulated heat is dispersed by switching on
the central heating pump. If boiler temperature rises to
89°C, the fan is switched on too.
- The cascade control function. The addition of a con-
troller (accessory) allows you to connect a number
of boilers in cascade, sharing heat output between a
number of burners and improving overall system effi-
ciency.
- Boiler switching differential. This establishes a mini-
mum off time for the burner, to stop it igniting and shut-
ting down repeatedly. The boiler will only start up again
if the difference between the setpoint and the actual
boiler temperature exceeds a predetermined value.
Notes on functioning
The control panel on the
TAU UNIT
boiler controls the following functions:
PROGRAMMING LEVELS
There are three programming levels:
- End user
- Installer
- Manufacturer
You must follow a precise set of instructions to access any of these levels. The relevant instructions, complete with a list
of the keys to press, are provided in the tables below.
END USER LEVEL
This level provides the parameters needed by the end user. For example, it contains parameters for setting CH and DHW
functioning times and Summer/Winter mode switching temperature.
See the “Complete list of parameters” section for further details.
Key
Explanation
1
D
U
Press one of these keys to access the END USER programming level.
2
D
U
Press one of these keys until you reach the parameter you require: the example here shows the parameter Pxx.
3
+
-
Press these keys to change the current value.
To memorise the new value, you need to move on to another parameter.
4
M
V
Press one of these keys to exit the end user programming level.
Any new settings are not stored in memory.
5
I
Press this key to exit the end user programming level.
Any new settings are stored in memory.
Note 1: If no key is pressed for about 8 minutes, the display automatically returns to the main screen. Any new
settings made will not be saved.
Note 2: Any changes are saved if you switch to another programming level.
