6
GENERAL
1 .3
Product description
This
TAU UNIT
condensing boiler is designed to produce
hot water for central heating systems. If used in conjun-
ction with a remote storage cylinder, it can also produce
domestic hot water. The innovative boiler body uses the
condensation of steam from the combustion gases to
recover up to 15% extra energy, with obvious benefits
in terms of running costs. The boiler body is made from
highly corrosion resistant stainless steel to guarantee an
extended working life and excellent reliability. The boi-
ler body conforms to the strictest Italian and European
standards governing the migration of heavy metals to
condensate. A premixed micro-flame burner guarante-
es extremely low emissions.
The control system applies compensated control logic to
maximise energy recovery in all seasons. The combu-
stion gases are cooled to a temperature near that of the
central heating return before they leave the boiler body.
This makes it possible to use plastic flue pipes instead
of metal ones, with significant savings in overall instal-
lation costs.
Special accessories are available to increase the number
of central heating circuits served, to cascade a number
of
TAU UNIT
boilers and to connect single or double re-
turn lines to suit the needs of the installation, impro-
ving heat stratification in the water inside the body and
optimising performance.
1 .4
Safety devices
This
TAU UNIT
condensing boiler is equipped with the following safety devices
An automatic
safety thermostat
that trips at 100° and
shuts down the burner.
An
electronic safety system
that monitors flow rate
through the central heating system using two sensors,
one on the flow pipe and the other on the return pipe.
This safety system forces the boiler to perform a safety
shutdown if flow rate is insufficient or not detected.
Flue gas safety thermostat
.
A flue gas thermostat in the bottom of the heat exchan-
ger that triggers an error condition if flue gas tempera-
ture exceeds 75°C. A flue gas temperature sensor in the
bottom of the heat exchanger that triggers a transient
error if flue gas temperature exceeds 85°C and a perma-
nent error if it exceeds 90°C.
A fan safety system
that uses a Hall effect speed sensor
to continuously monitor fan speed.
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The activation of a safety device indicates a poten-
tially dangerous malfunction in the modulation
system. Contact
R
’s Technical Assistance Service
immediately.
You may attempt to restart the boiler after a short
delay (see “Preparing for initial start-up”).
0
Never start the boiler up even for a short period if
the safety devices are not functioning correctly or
have been tampered with.
9
Safety devices must only be replaced by
R
’s Tech-
nical Assistance Service using original spare parts.
Refer to the spare parts catalogue supplied with the
boiler.
Always check that the boiler is functioning correctly after
any repairs.
