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