Riello TAU 35 UNIT Manual

cod. 20103677 rev. 1 05/16
TAU 35 UNIT
EN INSTALLATION AND MAINTENANCE MANUAL

2
ACCESSORIES
For a complete list of accessories and details of their compatibility, refer to the Catalogue.
RTAU UNIT condensing boilers conform to the following directives:
−Gas Appliances Directive 2009/142/EEC
−Boiler Efciency Directive 92/42/EEC and Annex E of the Italian Presidential Decree 412 dated 26 August 1993
−Electromagnetic Compatibility Directive 2014/30/UE
−Low Voltage Directive 2014/35/UE
−EN 677 Standard: Gas-red central heating boilers; specic requirements for condensing boilers with a no-
minal heat input not exceeding 70 kW.
−SVGW- Gas principles G1: Gas installation
−EKAS- Form. 1942: Liquid gas directive, Part 2
−Cantonal instances regulations (e.g. re safety regulators)
−Ecodesign Directive 2009/125/CE for energy-related products
−Energy Labelling Directive 2010/30/EU
−Delegated Regulation (EU) N. 811/2013
−Delegated Regulation (EU) N. 813/2013
CONFORMITY
RANGE
MODEL FUEL CODE
TAU 35 UNIT Methane - LPG 20101210

3
Dear heating engineer,
Congratulations on having chosen a R boiler. You have selected a modern, quality product that is designed to give
dependable, efcient and safe service and to provide comfort in the home for many years to come. This manual pro-
vides 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.

4
The following symbols are used in this manual:
9 = Identies actions that require caution and
adequate preparation
0 = Identies actions that you MUST NOT do
This manual, Code 20103677 Rev. 1 (05/16) is made up of
75 pages.
GENERAL ................................... 5
General safety information ...........................5
Precautions .......................................5
Product description .................................6
Safety devices .....................................6
Identication......................................7
Data plate ........................................7
Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Technical specications ..............................9
Water circuit ..................................... 10
Positioning the temperature sensors ....................11
Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Wiring diagram ................................... 15
Control panel......................................17
Programming levels ................................20
Information levels ................................. 22
INSTALLER .................................. 25
Unpacking the product .............................25
Opening ........................................25
Dimensions and weight.............................26
Handling ........................................26
Place of installation ................................ 27
Installation in older systems and systems requiring
modernisation.................................... 27
Water in heating circuits ............................28
Water connections.................................30
Draining the condensate ............................32
Condensate neutralisation unit .......................33
Gas connection ...................................35
Ch frost protection .................................35
Flue gas vent and comburent air intake.................36
Electrical connections .............................. 37
Sensor connections ................................38
Outdoor sensor connections .........................39
Filling and draining the system .......................40
TECHNICAL ASSISTANCE SERVICE....................41
Preparing for initial start-up ......................... 41
Initial start-up.................................... 41
Checks during and after initial start-up.................43
Temporary shutdown...............................44
Preparing for extended periods of disuse ...............44
Calibrating combustion parameters....................45
Setting functioning parameters ....................... 47
Error codes ......................................50
Complete list of parameters .........................63
Conversion from one gas type to another ...............69
Maintenance ......................................71
Removing the burner ...............................71
Positioning the electrodes ........................... 72
Cleaning the condensate drain and siphon .............. 72
Troubleshooting................................... 73
CONTENTS

5
GENERAL
The operation of any appliance that uses fuel, electrical power and water demands that a number of fundamental
safety precautions be respected.
9 As 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.
9 This TAU UNIT boiler must be installed by a legally
qualied heating engineer. On completion of the
installation, the installer must issue the owner with
a declaration of conformity conrming that the in-
stallation has been completed to the highest stan-
dards in compliance with the instructions provided
by Rin this instruction manual, and that it con-
forms to all applicable laws and standards.
9 This TAU UNIT boiler must only be used for the pur-
pose specied by Rand for which it is designed.
The manufacturer declines all responsibility, con-
tractual or other, for damage to property or injury to
persons or animals caused by improper installation,
adjustment, maintenance or use.
9 If you notice any water leaking from the boiler, di-
sconnect it immediately from the mains electricity
supply, shut off the water supply, and notify your
local R Technical Assistance Centre or a qualied
heating engineer immediately.
9 Periodically check that operating pressure in the
central heating circuit is over 1 bar but below the
maximum limit specied for the boiler. If water
pressure is consistently low, contact R’s Techni-
cal Assistance Service or a professionally qualied
heating engineer.
9 If the boiler is not going to be used for an extended
period of time, proceed as follows to prepare it for
shutdown:
−Switch the appliance OFF at the control panel.
−Turn the mains power switch OFF.
−Close the boiler’s fuel cock and heating circuit
water cock.
−Drain the central heating circuit and domestic
hot water circuit if there is any risk of freezing.
9 The boiler must be serviced at least once a year.
9 This instruction manual is an integral part of the
boiler. It must be kept safe and must ALWAYS ac-
company 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, or-
der a replacement immediately from your local R
Technical Assistance Centre.
0 Do not allow children or inrm persons to operate
the boiler unsupervised.
0 Do not operate any electrical devices or equipment,
including switches or domestic appliances, etc., if
you can smell fuel or fumes. If you detect any su-
spicious smells:
−Ventilate the room by opening all doors and win-
dows.
−Close the fuel shut-off cock.
−Report the fault immediately to your local RIELLO
Technical Assistance Service or a professionally
qualied heating engineer.
0 Do not touch the boiler when barefoot or wet.
0 Never clean or service the boiler without rst di-
sconnecting it from the mains electricity supply by
turning the main power switch and the control pa-
nel switch OFF.
0 Do not tamper with or adjust the safety or control
devices without prior authorisation and instruc-
tions from the boiler’s manufacturer.
0 Do not plug or block the condensate drain outlet.
0 Never pull, disconnect, or twist the electrical cables
coming from the boiler even if it is disconnected
from the mains electricity supply.
0 Do no obstruct or restrict the vents in the room
where the boiler is installed. Adequate ventilation
is essential for correct combustion.
0 Do not expose the boiler to the elements. Do not in-
stall the boiler outdoors. It is not designed to work
outdoors and is not tted with the necessary auto-
matic anti-frost systems to do so.
0 Do not store containers of ammable substances in
the room where the boiler is installed.
0 Do not dispose of packaging material into the en-
vironment, or leave it within the reach of children,
since it can become a potential hazard. Dispose of
packaging material in compliance with applicable
legislation.
1.2 Precautions
1 GENERAL
1.1 General safety information

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 benets
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-ame 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 ue pipes instead
of metal ones, with signicant 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 stratication 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 ow rate
through the central heating system using two sensors,
one on the ow pipe and the other on the return pipe.
This safety system forces the boiler to perform a safety
shutdown if ow rate is insufcient or not detected.
Flue gas safety thermostat.
A ue gas thermostat in the bottom of the heat exchan-
ger that triggers an error condition if ue gas tempera-
ture exceeds 75°C. A ue gas temperature sensor in the
bottom of the heat exchanger that triggers a transient
error if ue 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.
9 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.

7
GENERAL
Central heating circuit characteristics
Qn Rated heat input
Pn Rated useful heat output
IP Index of protection
P.min Minimum pressure
Pms Maximum operating pressure, CH system
TTemperature
η Efciency
NOxNOxclass
PAESE DI DESTINAZIONE: - PAYS DE DESTINATION:
LAND VON BESTEMMING: - BESTIMMUNGSLAND:
BESTEMMELSESLAND:
T067697GE
CALDAIA REGOLATA PER: - CHAUDIERE REGLEE POUR: VERWARMINGSKETEL INGESTELD OP:
KESSEL GEREGELT FÜR: - KJEL INNSTILT FOR:
European Directive
92/42/EEC:
η=
η=
η=
η=
N°
230 V ~ 50Hz W
Pms= bar T = °C
Qn(min) =
Pn(min) =
NOx:
IP P.min.G20= mbar
Qn(max =
Pn(max) =
Cod.
kW
kW
kW
kW
kW
kW
kW
kW
RIELLO S.p.A.
Via Ing.Pilade Riello
737045 Legnago (VR) - ITALY
Categoria:
Categorie:
Kategorie:
Kategori:
Combustibile: Combustible:
Brandstof: Brennstoff:
Drivstoff:
T067697GE
Caldaia a condensazione - Chaudière à condensation
Brennwertkessel - Condenserende verwarmingsketel - Kondenskjel
G25 BE
C63,C63x verboden in België - C63,C63x défendu en Belgique
>
-
Max. fluegas loss: 7 %
/
1.5 Identication
The boiler is identied by the following plates and labels
−Data plate
This lists the boiler’s technical specications and performance.
−Serial number plate
This species the serial number,
model, and furnace power.
PAESE DI DESTINAZIONE: - PAYS DE DESTINATION:
LAND VON BESTEMMING: - BESTIMMUNGSLAND:
BESTEMMELSESLAND:
T067697GE
CALDAIA REGOLATA PER: - CHAUDIERE REGLEE POUR: VERWARMINGSKETEL INGESTELD OP:
KESSEL GEREGELT FÜR: - KJEL INNSTILT FOR:
European Directive
92/42/EEC:
η=
η=
η=
η=
N°
230 V ~ 50Hz W
Pms= bar T = °C
Qn(min) =
Pn(min) =
NOx:
IP P.min.G20= mbar
Qn(max =
Pn(max) =
Cod.
kW
kW
kW
kW
kW
kW
kW
kW
RIELLO S.p.A.
Via Ing.Pilade Riello
737045 Legnago (VR) - ITALY
Categoria:
Categorie:
Kategorie:
Kategori:
Combustibile: Combustible:
Brandstof: Brennstoff:
Drivstoff:
T067697GE
Caldaia a condensazione - Chaudière à condensation
Brennwertkessel - Condenserende verwarmingsketel - Kondenskjel
G25 BE
C63,C63x verboden in België - C63,C63x défendu en Belgique
>
-
Max. fluegas loss: 7 %
/
230-50
IT-FR-CH-BE
B23,B23P,C13,C33, C63
GASOLIO-FIOUL-HEIZÍL
European Directive
92/42/EEC:
Pms= bar T = °C
Qn(min)=
Pn(min)=
TIPO/TYP/TYP:
COMBUSTIBILE/COMBUSTIBLE/BRENNSTOFF/BRANDSTOF:
Qn(max)=
Pn(max)=
Mod. Cod. N°
kW
kW
kW
kW kW
D= l/minkW
kW
kW
Pmw= bar T = °C
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
η =
η = η =
η =
PAESE DI DESTINAZIONE/PAYS DE DESTINATION/BESTIMMUNGSLAND/LAND VON BESTEMMING:
CALDAIA A CONDENSAZIONE CHAUDIÈRE À CONDENSATION
BRENNWERTKESSEL CONDENSERENDE VERWARMINGSKETEL
°C
MAX TEMP. FUMI - MAX TEMPÉRATURE FUMÉES MAX. ABGASTEMPERATUR - MAX. TEMPER. ROOKGASSEN
−Gas label
This is applied at the rear of the boiler
and species the type of gas used by
the boiler, and the country in which
the boiler is destined for use.
1.6 Data plate

8
GENERAL
1
2
3
7
5
4
6
8
9
11
10
12
13
14
15
3
4
6
16
17
18
19
20
1 Control panel
2 Front panel
3 CH pump
4 CH expansion vessel
5 Boiler body
6 CH circuit drain cock
7 Condensate drain siphon
8 Condensate drain pipe
9 Flue gas exhaust tting
10 Comburent air intake tting
11 Cover panel
12 Pressure switch (for combustion chamber)
13 Automatic vent valve
14 Safety valve (3 bar)
15 Sensor sockets
16 Gas valve
17 Gas tting
18 Burner
19 Central heating ow
20 Central heating return
1.7 Layout

9
GENERAL
MODELS TAU 35 UNIT
Device type
condensing boiler
for central heating
C13-C33-C43-C53
Fuel G20-G31
Device category II 2H3P
Maximum rated heat input at furnace referred to HVC (LCV) 38,6 (34,8) kW
Minimum rated heat input at furnace referred to HVC (LCV) 7,8 (7,0) kW
Useful (rated) heat output G20 34 kW
Maximum rated heat output 80-60°C (P4) G20 34,0 kW
Maximum rated heat output 50-30°C G20 37,0 kW
30% heat output with return at 30°C (P1) G20 10,2 kW
Minimum rated heat output 80-60°C G20 6,7 kW
Efciency class in central heating mode A
Seasonal energy efciency in central heating mode ηs91 %
Efciency at rated heat input in high temperature
mode (HCV) η4Useful Pn
(60-80°C) 88,0 %
Efciency at 30% rated heat input in low temperature
mode (HCV) η1 Useful 30%
of Pn 96,9 %
Losses from stack with burner off 0,1 %
Losses from stack with burner on 1,9 %
Heat loss in standby mode Pstby 34 W
Annual energy consumption QHE 107 GJ
Noise level (sound power) LWA Max 51 dB(A)
LWA Min 43 dB(A)
Emissions NOx NOx(referred to HCV) 29 mg/kWh
Emissions at max./min. heat input, G20
CO29,15 %
CO 5-10 ppm
Flue gas T. 71-55 °C
Emissions at max./min. heat input, G25
CO2(referred to HCV) 9,2-9,15 %
CO 4-10 ppm
Flue gas T. 59-55 °C
Pressure in combustion chamber 1mbar
Flue gas mass ow rate 0,016 Kg/s
Water-side pressure drop (∆t 10°C) 50 mbar
Maximum working pressure 3bar
Minimum supply pressure 0,5 bar
Safety thermostat trip temperature 100 °C
Maximum operating temperature 100 °C
Boiler water capacity 56 l
Volume of expansion vessel (CH) 12 l
Maximum condensation at 100% rated heat output (40-30°C) 4,5 l/h
Power supply 230-50 V-Hz
Electric degree of protection X0D IP
Absorbed power supply (max) 153 W
Consumption at full load Elmax 100 W
Consumption at part load Elmin 30 W
Consumption in standby mode PSB P sb 15 W
1.8 Technical specications

10
GENERAL
GAS
1
2
4
3
10
12
13
14
5
6
7
8 9
11
MI1
MI2
MB
RI1
RI2
RB
1 Boiler body
2 Gas valve
3 Fan
4 Burner
5 Automatic vent valve
6 Safety valve (3 bar)
7 Temperature sensor sockets
8 CH pump
9 Non-return valve
10 CH expansion vessel
11 CH circuit drain cock
MI1 First direct zone ow
MI2 Second direct zone ow
(accessory)
MB Storage cylinder delivery
(accessory)
RI1 First direct zone return
RI2 Second direct zone return
(accessory)
RB Storage cylinder return
(accessory)
GAS Gas supply
12 Condensate drain siphon
13 Flue gas exhaust pipe
14 Air intake pipe
1.9 Water circuit