Riello TAU 1750 N Service manual

cod. 20172279 rev. 1 11/2020
TAU 1750 ÷ 3000 N
EN INSTALLATION, TECHNICAL ASSISTANCE SERVICE AND SYSTEM MANAGEMENT MANUAL

2
RANGE
MODEL CODE
TAU 1750 N 20162157
TAU 2100 N 20162158
TAU 2600 N 20162159
TAU 3000 N 20162160
ACCESSORIES
For a complete list of accessories and details of their compatibil-
ity, refer to the Catalogue.
ENGLISH
Dear Customer,
Thank you for choosing a Rboiler. You have purchased a
modern, high efciency, quality product that is designed to
give dependable and safe service and to provide comfort in
the home for many years to come. Arrange for your boiler to be
serviced regularly by an authorised Technical Assistance Service
R. Their personnel are specially trained to keep your boiler
efcient and cheap to run. They also stock any original spare
parts that might be required.
This instruction manual contains important instructions and
precautions that must be observed to ensure the efcient func-
tioning of your TAU N boiler.
Please accept our renewed thanks for your purchase
Riello S.p.A.
CONFORMITY
RTAU N boilers conform to:
−Directive 92/42/EEC on efciency requirements
−Electromagnetic Compatibility Directive 2014/30/EU
−Low Voltage Directive 2014/35/EU
−Regulation (EU) 2016/426
At the end of its life, the product should
be not be disposed of as solid urban
waste, but rather it should be handed
over to a differentiated waste collection
centre.

3
This manual, Code 20172279 - Rev. 1 (11/2020)
comprises 48 pages.
Contents
CONTENTS
The following symbols are used in this manual:
9 CAUTION! = Identies actions that require caution and
adequate preparation.
0 STOP! = Identies actions that you MUST NOT do.
Thismanual,Code
-Rev.
comprises
pages.
1 GENERAL INFORMATION ............................4
1.1 General Safety Information ......................4
1.2 Precautions..................................4
1.3 Description of the appliance .....................5
1.4 Control panels................................5
1.5 Identication ................................5
1.6 System layout ................................6
1.7 Burner combination ...........................7
1.8 Technical specications.........................9
2 SYSTEM MANAGER ................................10
2.1 Putting into service ........................... 10
2.2 Preparing for extended periods of disuse ...........11
2.3 Cleaning ....................................11
2.4 Maintenance.................................11
2.5 Useful information ........................... 12
3 INSTALLER.........................................13
3.1 Unpacking the product ........................ 13
3.2 Overall dimensions and weights ................. 14
3.3 Handling................................... 15
3.4 Installation premises ......................... 16
3.5 Positioning of sensor sockets ....................17
3.5.1 Water-side pressure drop ...................... 18
3.6 Water in central heating systems................. 19
3.6.1 Glycol .....................................20
3.7 Water connections ........................... 21
3.8 Schematic diagram ........................... 22
3.9 Condensate evacuation........................28
3.10 Neutralising the condensate ....................29
3.11 Discharge of combustion products ............... 31
3.12 Door hinges ................................32
3.13 Changing the direction of door opening ........... 32
3.14 Earth connection ............................34
3.15 Fitting the casing panels .......................35
4 TECHNICAL ASSISTANCE SERVICE..................38
4.1 Preparing for initial startup.....................38
4.2 Initial startup ...............................38
4.3 Checks during and after initial start-up ...........39
4.4 Maintenance................................40
4.5 Adjusting the door ...........................40
4.6 Cleaning the boiler ...........................45
4.7 External cleaning ............................46
4.8 Boiler inspection - water-side ..................46
4.9 Troubleshooting ............................. 47

4
GENERAL INFORMATION
GENERAL INFORMATION
1 GENERAL INFORMATION
1.1 General Safety Information
9 The boiler is delivered in separate crates. Check that it is
complete, undamaged and as ordered as soon as you re-
ceive it. Report any discrepancies or damage to the dealer
who sold it.
9 This product must be installed by a legally qualied heat-
ing engineer. On completion of the installation, the install-
er must issue the owner with a declaration of conformity
conrming that the installation has been completed to the
highest standards in compliance with the instructions pro-
vided by Rin this instruction manual, and that it con-
forms to all applicable laws and standards.
9 This product must only be used for the purpose for which it
is designed and made, as specied by R. Rdeclines
all responsibility, contractual or other, for damage to prop-
erty or injury to persons or animals caused by improper in-
stallation, adjustment, maintenance or use.
9 If 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 R’s Technical Assis-
tance Service or a qualied heating engineer immediately.
9 Periodically check that operating pressure in the water cir-
cuit is over 1 bar but below the maximum limit specied for
the boiler. If this is not the case, contact Technical Assistance
Service R or a professionally qualied heating engineer.
9 If the boiler is not going to be used for an extended pe-
riod of time, contact R’s Technical Assistance Service or
a qualied heating engineer to have it prepared for shut-
down as follows
−Switch the boiler OFF at the control panel
−Turn the main system switch "off"
−Close the fuel cock and heating circuit water cock
−Drain the central heating 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 accompany 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 replacement immediately from your local
R’s Technical Assistance Service.
1.2 Precautions
The operation of any appliance that uses fuel, electrical power
and water demands that a number of fundamental safety pre-
cautions be respected:
0 It is forbidden to use electrical devices or equipment, such
as switches, appliances, etc. if there is a smell of gas or un-
burnt products. If so:
−Ventilate the room, opening doors and windows
−Close the fuel shut-off cock
−Report the fault immediately to the R's Technical As-
sistance Service or a professionally qualied heating en-
gineer.
0 Do not touch the boiler while barefoot or wet.
0 Never clean or service the boiler without rst disconnect-
ing it from the mains electricity supply by turning the main
power switch and the control panel switch OFF.
0 Do not tamper with or adjust the safety or control devices
without prior authorisation and instructions from the man-
ufacturer.
0 Do not plug or block the condensate drain outlet.
0 Never pull, disconnect, or twist the electrical cables coming
from the appliance even if it is disconnected from the mains
electricity supply.
0 Do not obstruct or restrict the vents in the room where the
boiler is installed. Adequate ventilation is essential for cor-
rect combustion.
0 Do not expose the boiler to the elements. It is designed to
work indoors.
0 Do not switch the boiler off if outdoor temperature drops
below ZERO (risk of freezing).
0 Do not store containers of ammable substances in the
room where the boiler is installed.
0 Do not allow children or persons with reduced physical,
sensorial or mental abilities or with insufcient experience
and knowledge to operate this system without proper su-
pervision from the person responsible for its safe use.
0 Do not dispose of packaging material into the environment,
or leave it within the reach of children, since it can become
a potential hazard. Dispose of packaging material in com-
pliance with applicable legislation.
Generalinformation

5
GENERAL INFORMATION
GENERAL INFORMATION
1.3 Description of the appliance
TAU N R steel boilers are triple ue pass, condensing boilers
for installation in a boiler room. While they are designed pri-
marily for central heating purposes, in conjunction with a suit-
able storage cylinder they can also be used to produce domestic
hot water.
The parts of the boiler that are in contact with combustion
products are made of Titanium stabilized stainless steel, capa-
ble of providing the best possible resistance to corrosion caused
by acid condensate.
The boiler has been designed with the combustion chamber at
the top and the smooth pipe tube bundle at the bottom to opti-
mise heat exchange and energy efciency and to maximise the
condensing effect.
The boiler has a high total water content which is differential-
ly distributed between its top and bottom sections. This al-
lows outgoing water to reach the set temperature quickly while
maintaining the condensing effect and the water heating time
around the tube bundle for as long as possible.
TAU N boilers feature lightly pressurised combustion chambers
for a smoother burner action, and high temperature resistant,
stainless steel turbulators inside the tube bundle for maximum
burner efciency.
The boiler body is thoroughly insulated with a layer of high den-
sity glass wool.
The paint nished external panelling is also internally insulated
with a layer of high density glass wool.
The boiler’s front door and the ue gas chamber can be opened
completely to facilitate the inspection, maintenance and clean-
ing of internal parts and to speed up servicing in general.
The front door can open in either direction and can be opened
without removing the burner. The door is factory tted with
hinges on the left, but these can be reversed if necessary to suit
individual installations.
1.4 Control panels
The steel boilers RTAU N can be combined with the control
panels of the RIELLOtech range which take into account the dif-
ferent operating functions, the needs of the heating system and
the various devices used on them.
Note: for additional information, see the Listocatalogo
1.5 Identication
The products are identied by:
Serial number plate
This is located on the boiler body and species the serial
number, model, and furnace power.
23270000581
WEEK OF
MANUFACTURE
CALDAIA IN ACCIAIO
Modello Matricola
Codice
Code
Anno fabbricazione Tipo
Type
Portata term. Pot. utile
Pres. Max esercizio
Aliment. elettrica
kW
T°Max ammessa
Contenuto acqua
°C
l
Combustibile utilizzato : TUTTI I GAS / GASOLIO
max (Hi)
Qmax
60°/80°
P
PMS
Pressione focolare
kW
pn
PER CATEGORIA COMBUSTIBILE
E PAESI DI DESTINAZIONE VEDI ETICHETTA BRUCIATORE
Portata term. min (Hi)
QkW Pot. utile kW
Tmax
m²
Superficie di scambio
mbar
RIELLO S.p.A.
Via Ing.Pilade Riello 7
37045 Legnago (VR) - ITALY
066940IE
STEEL BOILER
Model Serial number
Codice PIN
PIN number
Year of manufacture
Max. heat input
Min. heat input
Furnace pressure
Max. operating
pressure
T°Max permitted
Max. useful
heat output
60°/80°
P
min
heat output
Min. useful
Water capacity
Heat exchange
surface area
VEDI QUADRO ELETTRICO - SEE ELECTRIC CONTROL PANEL
Collegamento di terra obbligatorio - Obligatory ground connection
Fuel : GAS / OIL
FOR FUEL TYPE COUNTRY
OF DESTINATION SEE BURNER DATA PLATE
Power supply
Pa
k
Matricola
Modello
Pres. Max esercizio
Portata term. Qmax (Hi)
PMS
kW
RIELLO S.p.A.
Via Ing.Pilade Riello 7
37045 Legnago (VR) - ITALY
Serial no.
Model
Max.operating press.
Max. heat inpt
COMBUSTIBILE UTILIZZATO / FUEL: GAS, GASOLIO / GAS, OIL
Pa
k
Data plate
This lists the technical specications and performance of the
product. It comes inside the documentation envelope. On
completion of the installation you MUST apply it in a clearly
visible position at the top of one of the side panels. If you
damage or lose this label, order a replacement immediately
from R's Technical Assistance Service.
9 If these plates or any other means of clearly identifying the
product are defaced, removed or lost, proper installation
and servicing may be rendered difcult.

6
GENERAL INFORMATION
GENERAL INFORMATION
1.6 System layout
TAU N 1750 ÷ 3000
3 4 5 6 7
8
9
15
10
11
14
12
13
1 2
1 Burner
2 Flame inspection window with pressure meas-
urement tting
3 Door
4 Body interior inspection ange
5 Outlet
6 Safety device tting
7 Heating return (high temperature)
8 Combustion chamber
9 Heating return (low temperature)
10 Flue gas box
11 Flue gas exhaust
12 Inspection window
13 Condensate outlet
14 Boiler drain
15 Support surface - maximum load 150 kg

7
GENERAL INFORMATION
GENERAL INFORMATION
1.7 Burner combination
BURNERS TAU N Burner ange Long head
MODEL 1750 2100 2600 3000 Accessory
(compulsory)
Accessory
(compulsory)
Standard GAS (yellow ame)
RS 190/M TL ●
RS 250/M MZ TL ●20164364
RS 310/M MZ ●(2)
RS 410/M MZ ● (1) ●(2)
RS 510/M MZ ● (1) (2)
LOW NOX GAS
RS 200/M BLU TL ●
RS 310/M BLU ●(2)
RS 410 M BLU ● ●
RS 510 M BLU ● (1) (2)
RS 200/E BLU ● (1) (2)
RS 310/E BLU ●(2)
RS 410/E BLU ● ● (2)
RS 510/E BLU ● (1) (2)
|b|MIXED Gas / Standard light oil|bb
RLS 250/M MZ ●
MIXED Gas / Light oil Low NOX
RLS 310/M MX ● ● (2)
RLS 410/M MX ●(2)
RLS 510/M MX ●(2)
RLS 310/E MX ● ● (2)
RLS 410/E MX ●(2)
RLS 510/E MX ●(2)
GAS - PREMIX
RX 1800 S/E ●20163866
RX 2500 S/E ●20163866
RX 3000 S/E ● ● 20163866
(1) For altitudes over 1800 meters
(2) To replace on the burner head tted as standard
NOTE: burners must be tted with a gas ramp device.
9 See the instruction manual provided with the burner:
−Burner installation
−Electrical connections
−Burner adjustments
9 To assemble/disassemble the burners equipped with recirculation tube, it might be necessary to remove the latter before car-
rying out such operations (strictly comply with the use and maintenance manual of the burner).

8
GENERAL INFORMATION
GENERAL INFORMATION
IMPORTANT NOTES FOR BURNER INSTALLATION
Before xing the burner to the boiler, make sure that:
−The door opens the right way (see the relevant sections
for details on how to reverse the door)
−The length (L) of the burner xing bolts is less than (S),
i.e. the total depth of the seal, plates and washer. Longer
bolts can cause the door to warp, compromising its
ability to seal the boiler hermetically and permitting
the release of combustion fumes.
To ensure correct burner installation, also refer to the burner’s
own manual.
RS gas - RLS gas/Light oil burner
RX premix burner
If you are installing a new boiler but re-using an old burner,
always perform the following checks:
−Make sure that the performance of the old burner is ad-
equate for the requirements of the boiler
−Make sure that the length and diameter of the burner
nozzle are as specied in the following table.
9 When you nish installing the burner in the boiler, ll the
gap between the burner’s blast tube and the refractory ma-
terial in the door with the ceramic insulation (A) supplied
with the boiler.
A
Ø
L
A
A
TAU N
1750 2100 2600 3000
Burner head
L min. (mm) 350 350 350 500
Hole in door
Ø (mm) 520 520 520 520
0 Do not re-use old burners if their blast tube lengths are be-
low those specied in the table.

9
GENERAL INFORMATION
GENERAL INFORMATION
1.8 Technical specications
DESCRIPTION TAU N
1750 2100 2600 3000
Device type Condensing boiler for central heating B23 - B23P (*)
Fuel All GASES
Device category See Burner
Rated heat input (Q max) GCV (NCV) 1943,0 2331,0 2886,0 3330,0 kW max
(1750) (2100) (2600) (3000)
Rated heat input (Q min) GCV (NCV) 1611,5 1943,6 2332,1 2887,1 kW min
(1451) (1751) (2101) (2601)
Useful (rated) heat output 1718,5 2062,2 2553,2 2946,0 kW max
Minimum nominal useful output (80/60°C) ( Pn min) 1424,0 1721,2 2065,3 2556,8 kW min
Maximum useful output (40/30°C) 1881,2 2258,7 2796,5 3226,8 kW max
30% heat output with return at 30°C (P1) 570,7 684,8 847,9 978,3 kW max
Efciency at rated heat input and in High tempera-
ture mode n4 ( 80/60°C) GCV NCV
88,5 88,5 88,5 88,5 %
(98,2) (98,2) (98,2) (98,2)
Useful efciency at Pn min (80/60°C) HCV (LCV) 88,6 88,6 88,6 88,6 %
(98,3) (98,3) (98,3) (98,3)
Useful efciency at Pn Max (40/30°C) GCV (NCV) 96,9 96,9 96,9 96,9 %
(107,5) (107,5) (107,5) (107,5)
Efciency at 30% rated heat input and in Low tem-
perature mode n1 with return 30°C GCV (NCV)
97,9 97,9 97,9 97,9
%
(108,7) (108,7) (108,7) (108,7)
Losses from stack for sensible heat (Qmax) 1,5 %
Losses from casing with burner on 0,3 %
Constant pressure drop (P.max) < 0,2 %
Flue gas temperature < 45÷75 (**) °C
Mass ue gas ow rate (Qmax) (***) 0,75 0,93 1,14 1,32 kg/sec
Furnace pressure 8,4 9,6 11,5 11,6 mbar
Furnace volume 1593,0 1810,0 2270,0 2632,5 dm3
Tot. volume of ue gas side 2525,0 3040,0 3830,0 4440,0 dm3
Total surface area for heat exchange 77,7 93,2 115,7 136,0 m2
Volumetric thermal load (Q.max) 1098,6 1160,2 1145,4 1139,6 kW/m3
Specic heat load 22,5 22,5 22,5 22,1 kW/m2
Max. condensate production Full load 30/50 °C 173,0 203,0 256,0 301,0 l/h
Max. operating pressure 6bar
Maximum permitted temperature 100 °C
Maximum operating temperature 90 °C
Pressure drop ∆T 10°C 30 78 56 mbar
Pressure drop ∆T 20°C 12 31 21 mbar
Water capacity 3060 3330 4700 5560 liters
Turbulators n. 158 175 194 224 No.
(*) The B23P conguration may only be adopted with premix gas burners.
(**) Depends on return temperature (30-60°C)
(***) At Pn max and Tm = 80°C, Tr = 60°C e CO2 = 10,3%
9 The stack must guarantee the minimum draught specied by applicable technical standards, assuming zero pressure at the
connection to the ue.

10
SYSTEM MANAGER
SYSTEM MANAGER
2 SYSTEM MANAGER
2.1 Putting into service
Have R’s Technical Assistance Service start up your RTAU N
boiler for the rst time. Once this has been done, the boiler can
be left to function automatically.
Under certain circumstances, such as after long periods of dis-
use, the service engineer responsible for the boiler may need
to re-start it without involving the Technical Assistance Service.
To do so, perform the following checks and operations:
−Check that the gas cock and heating water cock are open
−While the system is still cold, check that working pressure
in the central heating circuit is over 1 bar but below the
maximum limit specied for the boiler
−Since the control panel incorporates a temperature con-
trol function, make sure that the control panel is switched
on
−Adjust the timer thermostat (if installed) or the tempera-
ture control to the desired temperature (~20° C)
−Turn the boiler’s mains power switch ON
−Turn the control panel power switch ON and make sure
that the green power indicator lights
−Make the settings as instructed in the instruction manual
for your control panel.
The burner should now ignite and remain in operation until the
set temperature is reached.
The burner will then switch off and on automatically to main-
tain the set temperature without further operator action.
If any ignition faults or malfunctions occur, the burner performs
a “LOCKOUT SHUTDOWN”. This is shown by the red button light on
the burner and by the warning light on the control panel.
9 If a “LOCKOUT SHUTDOWN” occurs, wait about 30 seconds be-
fore resetting the burner.
To reset the burner, press the red button light on the burner and
wait until the ame ignites.
Repeat this operation 2-3 times at the most. If the problem per-
sists after that, call R’s Technical Assistance Service.
Systemmanager

11
SYSTEM MANAGER
SYSTEM MANAGER
2.2 Preparing for extended periods of disuse
If the boiler is not going to be used for an extended period of
time, perform the following operations:
−Turn the control panel power switch OFF and make sure
that the green power indicator goes out
−Turn the main system switch "off"
−Close the fuel cock and heating circuit water cock
−Drain the central heating circuit if there is any risk of
freezing.
9 Contact your local RTechnical Assistance Service if you
encounter any problems in completing the above proce-
dure.
2.3 Cleaning
Use a cloth damped in soapy water to clean the boiler’s external
casing.
To remove stubborn marks, use a cloth damped in a 50% mix
of water and denatured alcohol or a suitable cleaning product.
Carefully dry after cleaning.
0 Do not use abrasive cleaning pads or powder detergents.
0 Never clean the boiler without rst disconnecting it from the
mains electricity supply by turning the mains power switch
and the control panel switch OFF.
9 The combustion chamber and ue pipes must be cleaned
periodically by the manufacturer’s Technical Assistance Ser-
vice or by a qualied heating engineer.
2.4 Maintenance
Please remember that THE PERSON RESPONSIBLE FOR SYSTEM MAN-
AGEMENT MUST ENSURE THAT PROFESSIONALLY QUALIFIED HEATING
ENGINEERS UNDERTAKE PERIODIC MAINTENANCE AND COMBUSTION
EFFICIENCY MEASUREMENTS.
R’s Technical Assistance Service is qualied to satisfy these
legal requirements and can also provide useful information on
MAINTENANCE PROGRAMMES designed to guarantee:
−Greater safety
−Compliance with applicable legislation
−Freedom from the risk of nes in the event of spot checks.
Regular maintenance is essential for the safety, efciency and
durability of the boiler.
Servicing is a legal requirement and must be performed at least
once a year by a professionally qualied heating engineer.

12
SYSTEM MANAGER
SYSTEM MANAGER
2.5 Useful information
Seller:...............................................................................
Mr.: ..................................................................................
Address: ...........................................................................
Tel.:..................................................................................
Technical Assistance Service: ..............................................
Mr.: ..................................................................................
Address: ...........................................................................
Tel.:..................................................................................
Installer:...........................................................................
Mr.: ..................................................................................
Address: ...........................................................................
Tel.:..................................................................................
Date Work done
Fuel oil supplier: ...............................................................
Mr.: ..................................................................................
Address: ...........................................................................
Tel.:..................................................................................
Date Quantity
supplied Date Quantity
supplied Date Quantity
supplied Date Quantity
supplied

13
INSTALLER
INSTALLER
3 INSTALLER
3.1 Unpacking the product
The TAU N boiler is supplied in two separate packages.
The rst contains:
−Boiler body inside a protective cover (A);
−Burner blast tube protection jacket kit (2500x50 mm) (B)
(*)
−Burner blast tube protection jacket kit (2500x80 mm) (C)
(*)
−Special glass bre braid gasket (35x25 mm) (D) (*)
−Blanking plates kit (E) (*)
−Condensate drain syphon (F) (*)
−Exchange pipes cleaning group (brush) (G)
−Document envelope (H) containing:
−Instruction manual
−Technical data plate adhesive (to be applied to the
panelling when installing the boiler)
−Hydraulic test certicate
−Conventional warranty conditions
9 The instruction manuals are an integral part of the boiler,
therefore we recommend to read and keep them with care.
G
H
DCB
(*)
A
EF
(*) Inside the combustion chamber: B-C-D-E-F-G.
The second package contains the panelling, complete with the
assembly accessories, inside a protective cardboard box and a
wooden crate.
9 For the boiler to function correctly, it must be connected to a
Rcontrol panel and dedicated control accessories.
Installer

14
INSTALLER
INSTALLER
3.2 Overall dimensions and weights
P
P 1
H 1 H
L 1
L
DESCRIPTION TAU N
1750 2100 2600 3000
L1750 1750 1850 1950 mm
L1 1800 1800 1900 2000 mm
P3620 4020 4425 4640 mm
P1 3212 3612 4024 4206 mm
H1945 1945 2070 2170 mm
H1 1870 1870 1997 2097 mm
Net weight 4265 4750 5820 6750 kg

15
INSTALLER
INSTALLER
3.3 Handling
9 Before handling the appliance and removing the packaging,
wear PPE and use tools suitable for the appliance's size and
weight.
The product can be moved in two ways:
−Using a forklift truck with adequate lifting capacity.
−Using a hoist with adequate lifting capacity;
HANDLING WITH A FORKLIFT
Two pockets (A) for handling with a forklift are positioned in the
lower part and accessible from both sides of the boiler.
A
A
MOVING WITH A HOIST
Two lifting points (B) are provided for lifting with crane on the
upper part of the boiler. Proceed as follows to move the boiler
and remove the packaging:
−Remove the protective lm;
−Move the boiler to the place of installation, use a crane
for lifting and using only the lifting accessories provided
with it.
−If chains are used to lift the boiler, make sure that at least
two of the chains are load-bearing.
−Lift with the utmost care.
−Maintain an angle less than 45 degrees from the vertical
when lifting the boiler with chains or ropes.
−The crane must be operated by trained personnel.
9 The packaging material must be disposed of carefully and
must not be abandoned, as it is a source of potential dan-
ger.
B
B
9 Risk of injury resulting from the transport of heavy loads and
inadequate fastening of loads for transport.

16
INSTALLER
INSTALLER
3.4 Installation premises
RTAU N steel boilers must be installed in a dedicated boiler
room, with adequately sized vents, in compliance with applica-
ble laws and standards.
If at all possible, the boiler should be installed on a raised base
to stop the burner fan sucking up dust and to facilitate installa-
tion of a condensate drain system.
The boiler condensate drain must be located above the height of
the lid of the system’s condensate neutraliser.
The gas supply pipe must be installed in such away that the
boiler’s panelling can be removed and the front door opened
without having to remove the burner.
9 For Belgium boilers must be installed according to the NBN
D51.003 standard, the NBN B61.001 standard (output > 70
kW).
9 When installing the boiler, allow sufcient space around it
to access all safety and control devices and to permit easy
maintenance.
9 If the specic weight of the gas supply to the burner is
greater than the specic weight of air, install all electrical
parts at least 500 mm above oor level.
0 Do not install the boiler outdoors. It is not designed to work
outdoors and is not tted with the necessary automatic an-
ti-frost systems to do so.
≥1,5
m
≥
L
H
≥
1m
≥1,5
mB
≥1 m L
~ 0,1 m
DESCRIPTION TAU N
1750 2100 2600 3000
B - Width 1750 1750 1850 1950 mm
L - Length 3212 3612 4024 4206 mm
H - Overall height (boiler + base) 2045 2045 2170 2270 mm

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INSTALLER
INSTALLER
3.5 Positioning of sensor sockets
TAU 2100-2600 N
2
1
3
4
TAU N 1750 2100 2600 3000
Length of the socket min. max. min. max. min. max. min. max.
1 - Flow sensor socket connector (1/2") 70mm 150mm 70mm 150mm 70mm 150mm 70mm 150mm
2 - Overtemperature protection (1/2") 120mm 190mm 120mm 190mm 120mm 190mm 120mm 190mm
3 - Return sensor socket connector (1/2") 120mm 150mm 120mm 150mm 120mm 150mm 120mm 150mm
4 - Flue gases sensor socket connector (1/2" NPT) 120mm 190mm 120mm 190mm 120mm 190mm 120mm 190mm
9 Thermometric sockets are not provided. The socket connections are closed with metal plugs.

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INSTALLER
INSTALLER
3.5.1 Water-side pressure drop
Pressure drop [mbar]
0
10
20
30
40
50
60
70
80
90
100
010 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300
TAU N 2100
TAU N 2600
TAU N 3000
TAU N 1750
Flow-rate [m3/h]

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INSTALLER
INSTALLER
3.6 Water in central heating systems
INTRODUCTION
Water used in central heating systems MUST be suitably treated
to ensure the correct functioning of those systems and to guar-
antee an extended working life for boilers and all other system
components. This applies not only to existing systems but to
newly installed systems too.
Sludge, lime-scale and pollutants present in the water can cause
permanent damage to the heating unit, also within a short time
and regardless of the quality standards of the materials used.
Contact the Technical Assistance Service for any further informa-
tion on type and use of additives.
9 Always conform to the standards and legislation applicable
in the country of installation.
WATER IN CENTRAL HEATING SYSTEMS.
INSTRUCTIONS FOR THE DESIGN, INSTALLATION AND MANAGEMENT
OF CENTRAL HEATING SYSTEMS.
1. Chemical and physical characteristics of water
The chemical and physical characteristics of water used in cen-
tral heating systems must conform to the requirements of EN
14868 standard and to the following tables:
STEEL BOILERS
with furnace power > 150 kW
Initial lling
water
Regular
service water
(*)
ph 6-8 7,5-9,5
Hardness °fH < 5° < 5°
Electrical
conductivity μs/cm < 100
Chlorides mg/l < 10
Sulphides mg/l < 10
Nitrides mg/l < 10
Iron mg/l < 0,5
(*) values for water in system after 8 weeks of functioning
General note on water used to top up systems:
−If softened water is used to top up a system, 8 weeks of
functioning after topping up, verify that the water in the
system respects the above limits, in particular for electri-
cal conductivity
−This check is not necessary if demineralised water is used
to top up the system.
2. Central heating systems
9 Do not use automatic lling devices to add water to central
heating systems. Use a manual device instead and record
top-ups in the system service book.
9 If there are more than one boiler, they must all be put into
service either contemporarily or with a very low rotation
time during the initial period of service, so as to evenly dis-
tribute the limited quantity of initial lime-scale.
9 A ushing cycle must be programmed after the plant has
been installed to ush out any installation debris.
9 Water used to ll a system for the rst time and water used
to top it up must always be ltered (using synthetic or metal
mesh lters with a ltration rating of no less than 50 mi-
crons) to prevent sludge from forming and triggering de-
posit corrosion.
9 The heating system must be ushed out and cleaned with
good workmanship before lling up the existing systems.
The boiler may not be lled until after the heating system
has been ushed out.
2.1 New central heating systems
The system must be lled up slowly the rst time; once it is lled
and the air expelled it should never need to be topped up again.
Systems should also be operated at maximum working tem-
perature the rst time they are started up, in order to facilitate
de-aeration. (Gas is not released from the water at low temper-
atures).
2.2 Reconditioning old central heating systems
If a boiler has to be replaced, do not rell the entire central
heating circuit if the quality of water in it conforms to require-
ments. If the quality of water fails to conform to requirements,
either recondition the old water or separate the water circuits
(water in the boiler circuit must conform to requirements).

20
INSTALLER
INSTALLER
3. Corrosion
3.1 Deposit corrosion
Under-deposit corrosion is an electrochemical process, due to
the presence of sand, rust, etc., inside the mass of water. These
solid substances generally deposit on the bottom of the boiler
(sludge), on tube and pipe heads or in the gaps between pipes
and tubes.
Micro-corrosion phenomena may be triggered off owing to the
difference in electrochemical potential coming to be created
between the material in contact with the impurity and the sur-
rounding one.
3.2 Stray current corrosion
Corrosion from stray currents can occur due to the differing elec-
trical potentials between water in the boiler and the metallic
mass of the boiler or piping. This process leaves unmistakeable
traces i.e. small regular conical holes.
9 All metallic parts should be grounded by an efcient earth
cable for this reason.
4. Eliminating air and gas from central heating systems
If oxygen enters a circuit continuously or even intermittently
(e.g. in under-oor heating systems whose pipes are not pro-
tected by impermeable synthetic sheaths, in circuits with open
expansion vessels, or in circuits that require frequent top-ups)
always separate the boiler’s water circuit from the central heat-
ing circuit.
Mistakes to avoid and precautions.
From what we have seen it is therefore important to avoid two
factors possibly leading to the above mentioned processes i.e.
contact between air and water in the installation and regular
topping up with fresh water.
To eliminate contact between air and water (and to prevent the
latter from becoming oxidized), it is necessary:
−For the expansion system to be a closed vessel type, cor-
rectly scaled and with the correct pre-loading pressure
(to be regularly checked)
−For the installation to always be at a higher pressure
than that of the atmosphere at any point (comprising the
pump suction side) and under all running conditions (all
the water sealing and couplings in the installation are
designed to resist pressure towards outside, but not for
depression)
−That the installation will not be made with materials per-
meable to gas (e.g. plastic pipes for oor systems without
anti-oxygen barrier).
9 Lastly we would remind you that the warranty does not cov-
er breakdowns incurred by the boiler due to deposits and
corrosion.
3.6.1 Glycol
The percentage of propylene glycol which can be used is de-
pendent on the maximum delivery temperature and the project
ΔT as dened by the generator.
To calculate the maximum percentage, use the graph below.
Glycol [%]
0
5
10
15
20
25
30
35
40
050 55 60 65 70 75 80 85 90 95
∆t 20°C
∆t 10°C
Delivery temperature [°C]
To calculate the freezing temperature associated with the mix,
please see the technical datasheet for the product used.
IMPORTANT INFORMATION REGARDING HEAT-TRANSFER FLUIDS
Heat-transfer uids are particularly important for protecting the
system: efcient heat exchange, thanks to a good specic heat
capacity; anti-freeze properties, important for the life of the
system in the winter; and anti-corrosion properties to preserve
the heating system components.
When choosing a heat-transfer uid, consider the following:
−toxicity in the event of leakage, contaminating domestic
water or water for animal/human use/contact
−biodegradability in the event of leakage into the envi-
ronment
All heat-transfer uids recommended by Riello are non-toxic
and in large part biodegradable.
9 Choose the liquid carefully and manage the heating system
correctly to keep monitoring and maintenance work to a
minimum, and reduce uid changes.