Riello TAU UNIT OIL 35 B Instruction Manual

1
INSTALLATION, MAINTENANCE
AND SYSTEM MANAGEMENT MANUAL
CONDENSING BOILERS
TAU UNIT
OIL 35 B
OIL 55 B

2
MODEL CODE
TAU UNIT OIL 35 B 20035952
TAU UNIT OIL 55 B 20035954
TAU UNIT OIL rcondensing boilers conform to the following directives:
• Efficiency Directive 92/42/EEC(HHHH)
• Electromagnetic Compatibility Directive 2004/108/CE
• Ecodesign Directive 2009/125/CE for energy-related products
• Energy Labelling Directive 2010/30/EU
• Low Voltage Directive 2006/95/CE
• Delegated Regulation (EU) N.811/2013
• Delegated Regulation (EU) N. 813/2013
CONFORMITY
RANGE

3
Dear heating engineer,
Congratulations on having chosen a TAU UNIT OIL r boiler. You have selected a modern,
quality product that is designed to give dependable, efficient and safe service and to provide
comfort in the home for many years to come. This manual provides information that is essential to
the installation of the appliance. Used in conjunction with your own knowledge and expertise it will
enable you to install the appliance quickly, easily, and correctly.
Once again, please accept our thanks and our congratulations on your choice of product.
Riello S.p.a.

4CONTENTS
This manual, Code 20091420 Rev. 3(12/19) is made up
of 72 pages.
The following symbols are used in this manual:
b = Identifies actions that require caution and ade-
quate preparation.
a = Identifies actions that you MUST NOT do.
GENERAL ..............................5
General safety information ..................... 5
Precautions.................................. 5
Product description ........................... 6
Safety devices ............................... 6
Product identification .......................... 7
Data plate................................... 7
Design ..................................... 8
Technical specifications ....................... 10
Accessories ................................ 11
Water circuit ................................ 11
Location of sensors .......................... 12
Pumps .................................... 13
Functional wiring diagrams .................... 14
Control panel ............................... 15
Mode selection.............................. 18
User levels ................................. 21
SYSTEM MANAGER .....................23
Start-up.................................... 23
Temporary shutdown ......................... 26
Preparing for extended periods of disuse ......... 26
Cleaning ................................... 27
Maintenance................................ 27
Useful information ........................... 28
INSTALLER ............................29
Unpacking the product ....................... 29
Dimensions and weight ....................... 29
Handling................................... 30
Place of installation........................... 31
Installation in older systems and systems requiring
modernisation ............................. 31
Heating circuit water ......................... 31
Water connections ........................... 34
Draining the condensate ...................... 36
Electrical connections ........................ 36
Outside sensor connections.................... 39
Fuel connections ............................ 41
Flue gas outlet and comburent air inlet ........... 42
Filling and emptying the system................. 44
TECHNICAL ASSISTANCE SERVICE .......45
Preparing for initial start-up .................... 45
Initial start-up ............................... 46
Checks during and after initial start-up ........... 47
Temporary shutdown ......................... 48
Preparing for extended periods of disuse ......... 48
Maintenance................................ 49
Oil burner .................................. 50
Disassembling and cleaning the boiler ........... 64
Troubleshooting ............................. 67
CONTENTS

GENERAL 5
The operation of any appliance that uses electrical power demands that a number of fundamental safety precautions
be respected.
aDo not allow children or infirm persons to operate
the boiler unsupervised.
aDo not operate any electrical devices or equipment,
including switches or domestic appliances, etc., if
you can smell fuel or fumes. If you detect any suspi-
cious smells:
- Ventilate the room by opening all doors and win-
dows.
- Close the fuel shut-off cock.
- Report the fault immediately to the rTechnical
Assistance Service or a professionally qualified
heating engineer.
aDo not touch the boiler when barefoot or wet.
aNever clean or service the boiler without first discon-
necting it from the mains electricity supply by tur-
ning the main power switch and the control panel
switch OFF.
aDo not tamper with or adjust the safety or control
devices without prior authorisation and instructions
from the boiler’s manufacturer.
aNever pull, disconnect, or twist the electrical cables
coming from the boiler even if it is disconnected
from the mains electricity supply.
aDo no obstruct or restrict the vents in the room
where the appliance is installed. Adequate ventila-
tion is essential for correct combustion.
aDo not expose the boiler to the elements. It is not
designed for use outdoors.
aDo not switch the boiler off if outside temperature
drops below ZERO (risk of freezing).
aDo not leave flammable substances or containers in
the room where the boiler is installed.
aDo not dispose of packaging material into the envi-
ronment, or leave it within the reach of children,
since it can become a potential hazard. Dispose of
packaging material in compliance with applicable
legislation.
bAs soon as you open the packaging, check imme-
diately that the contents are all present and unda-
maged. Contact the rreseller from whom you
purchased the product if you notice any problems.
bThis TAU UNIT OIL rboiler must be installed by
a legally qualified heating engineer. On completion
of the installation, the heating engineer must issue
the owner with a declaration of conformity confir-
ming that the installation has been completed to the
highest standards in compliance with the instruc-
tions provided by rin this instruction manual,
and that it conforms to all applicable laws and stan-
dards.
bThe boiler must only be used for the purpose spe-
cified by rand for which it is designed. The
manufacturer declines all responsibility, contractual
or other, for damage to property or injury to per-
sons or animals caused by improper installation,
adjustment, maintenance or use.
bIf you notice any water leaking from the boiler,
disconnect it immediately from the mains electricity
supply, shut off the water supply, and notify your
local rTechnical Assistance Centre or a quali-
fied heating engineer immediately.
bPeriodically check that operating pressure in the
water circuit is over 1 bar. If water pressure is con-
sistently low, contact r’s Technical Assistance
Service or a professionally qualified heating engi-
neer.
bIf the boiler is not going to be used for an extended
period of time, proceed as follows to prepare it for
shut-down.
- Switch the appliance OFF at the control panel.
- Turn the mains power switch OFF.
- Close the fuel cock and heating circuit water cock.
- Drain the central heating circuit if there is any risk
of freezing.
bThis boiler must be serviced at least once a year.
bThis instruction manual is an integral part of the boi-
ler. It must be kept safe and must ALWAYS accom-
pany the boiler, even if it is sold to another owner or
transferred to another user or to another installation.
If you damage or lose this manual, order a replace-
ment immediately from your local r’s Technical
Assistance Centre.
General safety information GENERAL SAFETY INFORMATION
Precautions PRECAUTIONS
GENERAL

GENERAL
6
These TAU UNIT OIL boilers are high efficiency, fuel oil
burning condensing boilers for heating. They can also
produce domestic hot water if an optional remote storage
cylinder is installed.
These boilers may be used as type “C” boilers if the com-
burent air inlet is extended to draw in air from outside the
room where they are installed.
Used in conjunction with suitable optional water circuit
and electrical kits, these boilers can be used to serve up
to two central heating circuits (zones).
The most important technical features of these boilers are:
- The combustion chamber and heat exchange system
are specially designed and shaped to achieve the best
possible volume ratio.
- The primary heat exchanger features vitrified steel pi-
pes and wave turbulators to recover and transfer a large
proportion of the thermal energy carried by the combu-
stion fumes.
- The secondary heat exchanger is made from AISI 904L
stainless steel and recovers latent heat from the fumes,
boosting efficiency to up to 100.7% (50°C-30°C).
The exclusively designed heat exchange unit and se-
condary exchanger are insulated by ultra-efficient high
density glass wool. The controls and safety devices in the
electronic control panel conform to all applicable techni-
cal and safety standards.
A highly flexible controller permits an additional zone to
be served directly and also permits integration with r
solar heating systems without additional controllers.
TAU UNIT OIL r
boilers are equipped with the following safety devices:
- A safety valve that opens if pressure in the heating
circuit rises above the 3 bar threshold.
- A safety thermostat that forces the boiler to perform
a safety shutdown if temperature exceeds the safety
threshold (110°C).
- A flue gas thermostat in the bottom of the secondary
heat exchanger that triggers a fault condition if flue gas
temperature exceeds 90°C.
- Burner safety device: The fuel oil burner is equipped
with an electronic device to monitor correct implemen-
tation of the selected program. In the event of a fault,
this device sends the control panel a burner lockout
signal and displays a precise diagnostic signal.
bThe intervention of a safety device indicates a
potentially dangerous malfunction in the system,
and means that you must contact r’s Technical
Assistance Service immediately.
You may attempt to restart the boiler after a short delay
(see Preparing for initial start-up).
aNever start the boiler up even for a short period if
the safety devices are not functioning correctly or
have been tampered with.
bSafety devices must only be replaced by r’s
Technical 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.
Safety devices
SAFETY DEVICES
Product description
PRODUCT DESCRIPTION

GENERAL 7
Central heating
Qn Rated heat input
Pn Rated useful heat output
IP Index of protection
Pms Maximum operating pressure for
central heating system
TTemperature
ηEfficiency
TAU UNIT OIL r
boilers are identified by two plates:
b If these plates or any other means of clearly identifying the product are defaced, removed or lost, proper installa-
tion and servicing may be rendered difficult.
- Data plate
This lists the appliance’s technical specifications
and performance data.
- Serial number plate
This is located on the base of the boiler and speci-
fies the serial number, model, furnace power, and
maximum operating pressure.
European Directive
92/42/EEC:
Pms= bar T = ° C °C
Qn(min)=
Pn(min)=
TIPO/TYP/TYP:
COMBUSTIBILE/COMBUSTIBLE/BRENNSTOFF/BRANDSTOF:
Qn(max)=
Pn(max)=
Mod.
Cod.
N°
kW
kW
kW
kW
IP
WV~Hz
RIELLO S.p.A.
Via Ing.Pilade Riello 7
37045Legnago (VR) - ITALY
Mod. Cod. N°
Qn(max)kW
Pn(max)kW
bar
Pms
RIELLO S.p.A. Via Ing.Pilade Riello 7
37045 Legnago (VR) - ITALY
PAESE DI DESTINAZIONE/PAYS DE DESTINATION/BESTIMMUNGSLAND/LAND VON BESTEMMING:
CALDAIA A CONDENSAZIONE
CHAUDIÈRE À CONDENSATION
BRENNWERTKESSEL
CONDENSERENDE VERWARMINGSKETEL
MAX TEMP. FUMI - MAX TEMPÉRATURE FUMÉES
MAX. ABGASTEMPERATUR - MAX. TEMPER. ROOKGASSEN
IT-FR-CH-BE
B23,B23P,C13,C33, C63
230-50
GASOLIO-FIOUL-HEIZÍL
European Directive
92/42/EEC:
Pms= bar T = ° C °C
Qn(min)=
Pn(min)=
TIPO/TYP/TYP:
COMBUSTIBILE/COMBUSTIBLE/BRENNSTOFF/BRANDSTOF:
Qn(max)=
Pn(max)=
Mod.
Cod.
N°
kW
kW
kW
kW
IP
WV~Hz
RIELLO S.p.A.
Via Ing.Pilade Riello 7
37045Legnago (VR) - ITALY
Mod. Cod. N°
Qn(max)kW
Pn(max)kW
bar
Pms
RIELLO S.p.A. Via Ing.Pilade Riello 7
37045 Legnago (VR) - ITALY
PAESE DI DESTINAZIONE/PAYS DE DESTINATION/BESTIMMUNGSLAND/LAND VON BESTEMMING:
CALDAIA A CONDENSAZIONE
CHAUDIÈRE À CONDENSATION
BRENNWERTKESSEL
CONDENSERENDE VERWARMINGSKETEL
MAX TEMP. FUMI - MAX TEMPÉRATURE FUMÉES
MAX. ABGASTEMPERATUR - MAX. TEMPER. ROOKGASSEN
IT-FR-CH-BE
B23,B23P,C13,C33, C63
230-50
GASOLIO-FIOUL-HEIZÍL
European Directive
92/42/EEC:
Pms= bar T = ° C °C
Qn(min)=
Pn(min)=
TIPO/TYP/TYP:
COMBUSTIBILE/COMBUSTIBLE/BRENNSTOFF/BRANDSTOF:
Qn(max)=
Pn(max)=
Mod. Cod. N°
kW
kW
kW
kW
IP
WV~Hz
RIELLO S.p.A. Via Ing.Pilade Riello 7
37045Legnago (VR) - ITALY
Mod.
Cod.
N°
Qn(max)kW
Pn(max)kW
bar
Pms
RIELLO S.p.A.
Via Ing.Pilade Riello 7
37045 Legnago (VR) - ITALY
PAESE DI DESTINAZIONE/PAYS DE DESTINATION/BESTIMMUNGSLAND/LAND VON BESTEMMING:
CALDAIA A CONDENSAZIONE CHAUDIÈRE À CONDENSATION BRENNWERTKESSEL
CONDENSERENDE VERWARMINGSKETEL
MAX TEMP. FUMI - MAX TEMPÉRATURE FUMÉES MAX. ABGASTEMPERATUR - MAX. TEMPER. ROOKGASSEN
IT-FR-CH-BE
B23,B23P,C13,C33, C63
230-50
GASOLIO-FIOUL-HEIZÍL
Data plate DATA PLATE
Product identication PRODUCT IDENTIFICATION

GENERAL
8
3
2
1
7
11
8
10
12
13
20
19
10
8
14
9
6
14
16
4
4
21
17
7
15
18
17
5
4
TAU UNIT OIL 35 B
SIDE VIEW FRONT VIEW
TOP VIEW
1 - Top panel
2 - Front panel
3 - Side panel
4 - Secondary heat exchanger
5 - Condensate drain siphon
6 - Inspection panel
7 - Automatic vent valve
8 - Safety valve (3 bar)
9 - Boiler sensor sockets
10 - Boiler body
11 - Flame inspection window
12 - Burner bracket
13 - Burner
14 - Control panel
15 - Pressure gauge
16 - Comburent air inlet pipe
17 - Boiler drain cock
18 - Lifting eyebolts
19 - Socket for flue gas thermostat
20 - Flue gas exhaust
21 - Boiler body insulation
Design
DESIGN

GENERAL 9
3
2
11
12
19
18
20
21
13
10
9
13
14
16
15
17
5
7
4
14
20
17
8
7
6
5
4
1
TAU UNIT OIL 55 B
SIDE VIEW FRONT VIEW
TOP VIEW
1 - Top panel
2 - Front panel
3 - Side panel
4 - Automatic vent valve
5 - Safety valve (3 bar)
6 - Pressure gauge
7 - Secondary heat exchanger
8 - Condensate drain siphon
9 - Inspection panel
10 - Boiler sensor sockets
11 - Burner bracket
12 - Burner
13 - Control panel
14 - Boiler body
15 - Comburent air inlet pipe
16 - Flame inspection window
17 - Boiler drain cock
18 - Socket for flue gas thermostat
19 - Flue gas exhaust
20 - Lifting eyebolts
21 - Boiler body insulation

GENERAL
10
(*) Values referred to atmospheric pressure at sea level.
Description TAU UNIT
OIL 35 B OIL 55 B
Type of boiler
condensing boiler for
central heating
B23-B23P-C13-C33-C63
Fuel Heating fuel oil (Light oil)
Rated heat input at furnace referred to HVC (LCV) 36,6 (34,5) 58,4 (55) kW
Useful (rated) heat output 33 53 kW
Rated heat output (60-80°C) P4 33,3 53,1 kW
30% heat output with return at 30°C (P1) 10,0 15,9 kW
Efficiency class in central heating mode A
Seasonal energy efficiency in central heating
mode hs 90 91 %
Efficiency at rated heat input in high
temperature mode (HCV) h4Useful Pn (60-80°C) 91,0 91,0 %
Efficiency at 30% rated heat input in low
temperature mode (HCV) h1Useful 30% of Pn 96 96 %
Heat loss in standby mode Pstby 200 250 W
Annual energy consumption QHE 107 169 GJ
Noise level (sound power) LWA 70 71 dB(A)
Emissions at maximum heat input
NOx (referred to
HCV) 94 96 mg/kWh
Smoke scale < 0,5
CO2 12,5 %
CO w.a. < 23 ppm
Flue gas temperature Δt (80-60°C) 70 67
Δt (50-30°C) 44 46
Flue gas mass flow rate (*) 0,013 0,023 Kg/s
Flue gas thermostat trip temperature 90 °C
Water-side pressure drop (Δt 20°C) 50 75 mbar
Maximum working pressure 3 bar
Safety thermostat trip temperature 110 °C
Maximum operating temperature 82 °C
Minimum return temperature 30 °C
Boiler water temperature selection range 30-82 °C
Boiler water capacity 34 51 l
Secondary heat exchanger water capacity 7 9
Maximum condensation at 100% rated heat output (50-30°C) 2,2 3,8 l/h
Power supply 230-50 V-Hz
Electric degree of protection X0D IP
Consumption at full load Elmax 250 300 W
Consumption at part load Elmin 75 90 W
Consumption in standby mode PSB P sb 2 2 W
Technical specications
TECHNICAL SPECIFICATIONS

GENERAL 11
RI
MI
1
2
3
4
6
7
8
5
9
10
RI
MI
1
2
6
7
8
9
10
34
5
TAU UNIT OIL 35 B
TAU UNIT OIL 55 B
1 - Boiler body
2 - Secondary heat exchanger
3 - Automatic vent valve
4 - Pressure gauge
5 - Safety valve (3 bar)
6 - Burner
7 - Drain cock
8 - Condensate drain siphon
9 - Drains
10 - Flue gas exhaust
MI - CH flow
RI - CH return
ACCESSORY CODE
TAU UNIT OIL 35 B TAU UNIT OIL 55 B
Mixed zone kit 20039723 -
Second mixed zone electrical kit 20011194 / 20102310
Flue kit 80/125 20012802 20012802
Sealing kit 80/80 20012807 20012807
Solar collector sensor kit 4031913 4031913
Storage cylinder temperature sensor kit 4031847 4031847
Remote control RC2 4334410 4334410
Accessories ACCESSORIES
Water circuit WATER CIRCUIT

GENERAL
12
1
2
3
3
1
2
Characteristics of boiler, flow and storage cylinder sensors
Measured temperature (°C) - Resistance (Ω).
T (°C) R (Ω) T (°C) R (Ω) T (°C) R (Ω) T (°C) R (Ω)
-30.0 175203 30.0 8059 90.0 915 150.0 183
-25.0 129289 35.0 6535 95.0 786 155.0 163
-20.0 96360 40.0 5330 100.0 677 160.0 145
-15.0 72502 45.0 4372 105.0 586 165.0 130
-10.0 55047 50.0 3605 110.0 508 170.0 117
-5.0 42158 55.0 2989 115.0 443 175.0 105
0.0 32555 60.0 2490 120.0 387 180.0 95
5.0 25339 65.0 2084 125.0 339 185.0 85
10.0 19873 70.0 1753 130.0 298 190.0 77
15.0 15699 75.0 1481 135.0 262 195.0 70
20.0 12488 80.0 1256 140.0 232 200.0 64
25.0 10000 85.0 1070 145.0 206
TAU UNIT OIL 35 B
1 -
Boiler temperature sensor
2 - Safety thermostat sensor
3 - Flue gas thermostat sensor
TAU UNIT OIL 55 B
1 -
Boiler temperature sensor
2 - Safety thermostat sensor
3 - Flue gas thermostat sensor
Location of sensors
LOCATION OF SENSORS

GENERAL 13
aNever run the pump dry.
r TAU UNIT OIL boilers come without a pump. A pump must therefore be provided on installation.
In order to choose a pump of the right size, bear in mind the boiler’s water-side pressure drop, as shown in the figure below.
PRESSURE DROP (mbar)
FLOW-RATE (l/h)
0
0200025003000350040004500500015001000500
50
100
150
200
250
300
350
400
450
500
600
550
TAU UNIT OIL 35 B
TAU UNIT OIL 55 B
Pressure drop (mbar)
Flow rate (l/h)
Pumps PUMPS

GENERAL
14
TS TF
H2
L1
N
AP
PE
S3
T1
T2
RS
RS
H1
IMF
L N PE
230 V~50 Hz
Y1/QX4
Y2/QX2
BSB-4p BSB
NA/0-10VH1
Q2/QX5
QX1QX1
FX1
QX3
L1
PE
PE
T1
T1 N
N
T2
T2
X30-10pX30
L1
L1
S3
S3
N
N
B1/BX3
BX1 BX1
M
B2
B3
B9
M
BX2 BX2
LPB-4p LPB
M
X50-5p X50
X60-6p X60
LPB DB
MB
L
L
PE
PE
S3
S3
4
4
SK2
SK2 SK1
SK1
N
N
N
N
N
N
PE
PE
FX1
PE
PE
PE
PE
M
TA-M
MM
MM
MM
CL+ CL+
CL+ CL+
CL- CL-
CL- CL-
G+ G+
GX1 GX1
H3 H3
MM
SCH1
MO1
FU
6.3A-T
SC SE SMix1
1
N
2
VMix1
N
L1
PE
PIMix1
N
L1
PE
PB
TA
TA
0
1
IP
TA
TA
X30
T1
T2 T3
T4
T5T6
T7 T8
SCH2
SB
TSMix1
QX1QX1
Electrical connections to be made
by the heating engineer
Power supply
open
close
CH 1 phase
Storage
cylinder phase
1st stage
CH 1 snsr
ground
Boiler snsr
DHW 1 snsr
Out. temp. snsr
ground
ground
ground
QX1
IMF Multifunctional input (*) FU Fuse (6.3 A-T) IP Main switch SCH1 Main board SCH2 Display and control card TF Flue gas thermostat (90°C) TS Safety thermostat (110°C +0/-6) H1 Safety thermostat or flue gas thermostat trip indicator H2 Burner lockout indicator AP Burner controller RS Remote burner reset
QX1 Programmable output, parameter 5890 See the water connections section for further information. PIMix1 Mixed circuit pump (optional) VMix1 Mixer valve (optional) PB Storage cylinder pump (optional) SC Boiler sensor SE Outside sensor (supplied) SMix1 Mixed circuit flow sensor (optional) SB Storage cylinder sensor (optional) TSMix1 Mixed circuit safety thermostat (not supplied)(*) See parameters 5950-5951.
Functional wiring diagrams
FUNCTIONAL WIRING DIAGRAMS

GENERAL 15
PRIMARY USER INTERFACE / CONTROLS
1
8-9
1017 11
732 5 64
12131516 14
8
9
18
1 - Safety thermostat trip indicator.
2 - Electronic operator unit (controller).
3 - DHW production on/off button (only present if the optional remote storage cylinder is installed). A line appears
under the "v" symbol on the display when DHW production is enabled.
4 - Display.
5 - Central heating mode selection button. A line appears under the symbols:
sAUTOMATIC
oContinuous COMFORT
lContinuous REDUCED
FCOOLING
bFrost protection. The "t" symbol is displayed.
6 - Information button "i".
7 - Burner lockout indicator.
8 - Manual reset for flue gas thermostat. Unscrew the protective cover to access the reset button.
9 - Manual reset for safety thermostat. Unscrew the protective cover to access the reset button.
10 - Remote burner reset button.
11 - "p" button for chimney sweep/safety thermostat test functions.
12 - "R" button for manual mode
13 - Value confirm (OK) button.
14 - Value change knob.
15 - ESCape button.
16 - PC BUS connector.
17 - Main switch.
18 - Fuse.
bottom view
Control panel CONTROL PANEL

GENERAL
16
F
G
E
B
C
D
A
1
2
2
13
A - DHW mode: ON or OFF
B - Central heating modes:
sAUTOMATIC
oCONTINUOUS COMFORT
lContinuous REDUCED
FCOOLING
bFrost protection. The "t" symbol is displayed.
C - Small numeric display: time
D - Message area
E - Daily heating program indicator
F - Large numeric display: current value
G - Display symbols:
fBurner running
BChange battery (room unit only, not supplied)
wHoliday mode active
nError. Press the ibutton to display the error message.
Press ESC to return to the main screen.
C Wait: process running
hMaintenance - manual or chimney sweep mode
Reference to heating circuit
ECO Heating temporarily OFF - ECO mode active
SECONDARY USER INFORMATION / DISPLAY

GENERAL 17
- Frost protection: The pumps are switched on on the
basis of outside temperature irrespective of demand
for heat.
If outside temperature drops below -4°C the pumps
are switched on. If outside temperature is between -5°
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.
- Chimney sweep: The burner is ignited to obtain
the conditions necessary for combustion analysis.
To obtain continuous burner functioning, maximum
operating temperature is set at the boiler’s maximum
setpoint.
All loads are switched off to start with, in order to bring
the boiler to its 64°C setpoint as quickly as possible.
When the boiler reaches 64°C, the heating circuits are
opened one by one to dissipate the heat and allow the
burner to continue functioning.
- Limit thermostat (parameter 2310): This function shuts
the burner down if boiler temperature exceeds the
maximum permitted limit, which coincides with the boi-
ler’s maximum setpoint (parameter 2212 = 80 °C).
- DHW charging priority: if an optional remote storage
cylinder is installed and domestic hot water is drawn
off while the central heating circuit is also in use, this
function directs boiler power mainly to the DHW circuit.
- Boiler switching differential: This establishes a mini-
mum run time for the burner, to stop it igniting and
shutting down repeatedly. The burner shuts down
only if boiler temperature exceeds a predetermined
threshold (parameter 2240).
- Solar collector protection:
- Collector frost protection (param. 3840)
- Collector overtemperature protection (param. 3850)
- Pump protection against vapour in heat transfer fluid
(param. 3860)
G1
H1
F1
C1
D1
E1
A13B1
Boiler temperature
5
MAIN SCREEN
A1 - DHW production mode: ON or OFF.
Press the DHW button to (3) to switch DHW on or off
(as shown by the line under the symbol).
B1 - Central heating modes:
Press the central heating mode button (5) to activate the various modes as shown
by the line under the corresponding symbol.
C1 - Current time.
D1 - COMFORT heating mode.
E1 - Message area.
F1 - Daily heating program indicator.
G1 - Current boiler temperature
(If parameter 22 = “Permanently” the most recent information selected in
“Information mode” is displayed.)
H1 - Burner running.
Notes on functioning
The control panel on the TAU UNIT OIL rboiler controls the following functions.

GENERAL
18
Domestic hot water (DHW) v
An optional remote storage cylinder must be installed
before DHW production can be enabled. Press the DHW
button (3) to activate DHW production, as shown by a line
under the corresponding symbol.
ON: DHW is generated according to the DHW time pro-
gram (parameters 560 to 566).
OFF: DHW production is switched off but the protection
functions remain active.
b You can force DHW production (PUSH function) by
pressing and holding the DHW button (3) for at least
3 seconds.
Automatic s
In automatic mode, room temperature is controlled by the time program.
Characteristics:
- Central heating operates according to the time program.
- The temperature setpoint is set to comfort "o" or reduced "l".
- All protection functions are active.
- Summer/winter switching is automatic (ECO functions) and 24h limit functions are active.
Continuous operation o or l
In continuous mode, room temperature is controlled on the basis of the comfort/reduced setting:
o Central heating set to comfort setpoint
l Central heating set to economy setpoint
Characteristics:
- Central heating is continuously on with no time program.
- All protection functions are active.
- Summer/winter switching is automatic (ECO functions) and 24h limit functions are inactive if comfort level is selected
(see parameters 730 and 732).
Protection b
In protection mode the central heating is switched off, but the system remains protected against frost (provided the
electrical supply remains switched on).
Characteristics:
- Central heating is switched off.
- Temperature is set to the frost protection setpoint.
- All protection functions are active.
- Automatic summer / winter changeover and automatic 24-hour heating limit active (ECO functions)
Press the central heating mode button (5) to select the
various modes. The active mode is shown by a line under
the corresponding symbol.
5
Boiler temperature
3
Boiler temperature
Mode selection
MODE SELECTION

GENERAL 19
Setting the room temperature setpoint
Turn the knob (14) to set the desired room temperature
comfort setpoint.
Proceed in a similar way to set the room temperature redu-
ced setpoint.
- Press the "OK" button (13).
- Select “Heating circuit 1”.
- Set the room temperature reduced setpoint.
b After changing a setpoint, you need to wait about 2
hours for the new setting to have any effect on room
temperature.
b If no room unit is installed, changing the room tempera-
ture setpoint simply shifts the heating curve.
14 13 6
Comfort setpoint
Information i
Press the information button (6) to display:
- Errors or maintenance codes (see the “Errors/Maintenance codes” section).
- Special messages.
Other screens:
b Other screens depend on the system configuration and status. Some of the info lines shown below may not
therefore appear.
Chimney sweep mode R
When you select manual mode, the "h" symbol appears
and relays are energised/de-energised not according to
any heating program but according to a default manual
setting that can be set by pressing the information button
(6).
Chimney sweep mode p
To select chimney sweep mode, press the chimney
sweep button (11) briefly (max. 3 seconds). The "h"
symbol is displayed. Chimney sweep mode prepares the
boiler for combustion analysis. To exit chimney sweep
mode, press the button (11) again. The system exits
chimney sweep mode automatically after 1 hour.
12 11 6
Boiler temperature
- Room temperature
- Minimum room temperature
- Maximum room temperature
- Room 1 setpoint
- Room 2 setpoint
- Room 3 setpoint
- Cascade flow temperature
- Boiler temperature
- Outside temperature
- Minimum outside temperature
- Maximum outside temperature
- DHW 1 temperature
- DHW 2 temperature
- Buffer tank 1 temperature
- Buffer tank 2 temperature
- Buffer tank temperature setpoint
- Flow 1 temperature
- Flow 1 temperature setpoint
- Flow 2 temperature
- Flow 2 temperature setpoint
- Flow 3 temperature
- Flow 3 temperature setpoint
- Collector 1 temperature
- Wood fuelled boiler temperature
- Solar flow temperature
- Solar return temperature
- 24 hours solar energy yield
- Total solar energy yield
- Pool temperature
- Pool setpoint
- Heating circuit 1 status
- Heating circuit 2 status (not active)
- Heating circuit 3 status
- Cooling circuit state
- DHW status
- Boiler status
- Solar heating status
- Solid fuel boiler status
- Buffer storage tank status
- Pool state
- Error message
- Maintenance message
- Floor curing function
- Date and time
- Telephone number of technical assi-
stance centre

GENERAL
20
RESET function (parameter 6205)
The meters and parameter table RESET icon only appe-
ars in the bottom line of the display if it is possible to
perform a reset in the current user level (End user,
Commissioning, Heating engineer).
b This operation must only be performed by the r
Technical Assistance Service.
Performing a RESET restores all parameters to their
default values, according to the "Complete list of
parameters".
To perform a reset , press the "OK" button (13) when the
"Yes" prompt flashes on the display.
13
Temperatura caldaia
Reset ? yes
Special conditions nh
The following icons can be displayed under certain con-
ditions:
n
This symbol appears if a system error has occurred.
Press button (6) for further information.
h
This symbol appears if a maintenance alarm is present
or if the boiler has entered a special functioning mode.
Press button (6) for further information.
See also "Error/Maintenance codes".
Error
30: Flow sensor 1
Attention
3: Maintenance interval exceeded
6
6
Error
30: Flow sensor 1
Attention
3: Maintenance interval exceeded
6
6
Safety thermostat test p
To test the safety thermostat, press and hold the chimney
sweep button (11) for longer than 3 seconds.
Hold the button down for the duration of the test.
The test terminates as soon as you release the button.
b This test must only be performed by the r
Technical Assistance Service, since it raises boiler
temperature over the normal permitted limits.