Riello RTT Series User guide

cod. Doc-0079323 rev. 1 03/2016
RT T 378-930
EN INSTRUCTIONS FOR THE INSTALLER AND FOR THE TECHNICAL ASSISTANCE CENTRE

2
RANGE
MODEL CODE
RTT 378 20093090
RTT 448 20091316
RTT 506 20091318
RTT 564 20091321
RTT 610 20091325
RTT 663 20091326
RTT 715 20091329
RTT 773 20091334
RTT 831 20091335
RTT 878 20091337
RTT 930 20091339
ACCESSORIES
For the RTT 378-930 r boilers the following accessories are avail-
able:
a. Two stage kit – 4031067
b. Storage heater probe – 20010103
Dear client,
Thank you for choosing a Rboiler, a modern and high quality
product, providing you with the utmost well-being and with a
high level of reliability and safety; and this is particularly the
case if entrusted to a RTechnical Assistance Centre which is
specically capable of carrying out routine maintenance, keep
it running at maximum efciency, with low running costs and
which has original spare parts if required.
This instruction booklet contains important information and
suggestions that should be observed for easy installation and
better use of the RTT 378-930 boiler.
Thank you once again
Riello S.p.A.
CONFORMITY
TheRTT 378-930 r boilers comply with:
−2009/142/EC (ex 90/396/EEC-Gas Directive)
−92/42/EEC (Efciency Directive)
−2006/95/EC (ex 73/23/EEC-Low voltage Directive)
−2004/108/EC (ex 89/336/EEC-Electromagnetic Compatibility
Directive)
−EN 303/1-2-3
−EN 60335-1/2
−EN55014-1/2
−EN 61000

3
1.1 General warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 General characteristics of the RTT boilers.............. 5
1.3 Technical data.................................. 6
1.4 Boiler data plate .................................7
1.5 Dimensions.....................................7
1.6 Delivery........................................7
1.7 Installation of the boiler . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.8 Important information about the boiler room ......... 9
1.9 Hydraulic system................................10
1.10 Schematic diagram - system for heating and domestic
hot water production ............................10
1.11 Important instructions for connecting the fuel tank ..... 11
1.12 Important information about the ue pipe ........... 11
1.13 Control panels that can be combined ................12
1.14 High performance cast iron elements................12
1.15 Ventilation of the boiler room ......................12
1.16 Gas side resistor and output temperature of combustion
gases ........................................13
1.17 Instructions for use ..............................13
1.18 Conveyance and discharge of the boiler water .........14
1.19 Instructions for disposing of the product .............14
1.20 Fire prevention regulations for the boiler room.........14
1.21 Controls and starting the boiler.....................14
1.22 Maintenance instructions .........................15
1.23 Cleaning the boiler ..............................15
1.24 Burner door and burner connection.................16
1.25 Table of burner combinations ......................17
1.26 Transport and storage ............................18
1.27 Useful information ..............................19
CONTENTS
In some parts of the booklet, some symbols are used:
9 = for actions requiring special care and adequate preparation
0 = for actions THAT MUST NOT be performed
This booklet, Cod. Doc-0079323 - Rev. 1 (03/2016) is composed of 20 pages.

4
panel and the boiler should be carried out by qualied per-
sonnel in compliance with the reference regulations and
standards.
9 The burner should be purchased separately, this manu-
al contains only information regarding the boilers and the
boiler warranty does not extend to the burner. It is neces-
sary to consult the burner's instruction manual and have
the Warranty Certicate issued for the burner by the dealer
where it was purchase.
9 Before starting the burner, make sure that the front door of
the boiler is closed tight and that the burner connections
have been carried out correctly.
9 Do not touch the hot water pipes and the ues gases dis-
charge pipe when the boiler is running.
1.1 General warnings
The boiler models that are the subject of this manual are sup-
plied disassembled of the boiler body.
9 The cast iron RTT 378-930 boilers are designed for heating
using water and/or supplying hot water systems and have
been designed with technologies and materials suitable for
this purpose. Use the product only for this intended use.
9 The installation of the appliance should be carried out on a
base that is suited to the weight and the dimensions.
9 The base of the boiler should be positioned and oriented in
such a way as to leave sufcient space on the sides of the
appliance to meet safety requirements and permit access to
the boiler for maintenance and repairs.
9 The commissioning and initial ignition of the boiler should
only be carried out by specialised installers.
9 It is forbidden to put or pump water into the boiler or the
hydraulic system when the appliance is running and is hot.
9 Before putting water in the boiler or the system, it is neces-
sary to wait for the water temperature to reach 40° C. When
putting water into the system, always run the circulation
pump to prevent breaking the elements.
9 When the boiler is off for a long period or when carrying out
repairs, maintenance or cleaning, the electrical supply must
be disconnected using the master switch.
9 Especially in summer, when the boiler is off for a long pe-
riod, to avoid problems of incrustation in the circulation
pumps, the boiler must be switched on 1-2 times a month
and the circulation pumps operated for at least 5 minutes.
Limescale in the water can cause problems if the pump is
unused for a long period.
9 Choose a boiler with the right dimensions for the project
in full compliance with applicable regulations. If the wrong
size is chosen, the performance will suffer.
9 The RTT 378-930 boilers are only to be used for heating. For
the production of domestic hot water, it is necessary to use
a storage heater or another heat exchanger. For it to work
efciently, pay special attention to the size of the domestic
hot water circuit.
9 The RTT 378-930 boilers are delivered without the burner. To
choose the most suitable burner and keep the performance
high, contact technical personnel.
9 If the boiler goes into lockout automatically because of over-
heating, do not put cold water inside to get it going again.
Wait until the boiler cools down, and try to restart it. If this
does not happen, contact the Technical Assistance Service.
9 Periodically check the boiler and the burner. If these period-
ic controls are not carried out, performance will suffer and
there will be an increase in fuel consumption. The period-
ic and annual controls of the boiler should be carried out
carefully and at the pre-established time. Natural gas is a
clean fuel and does not dirty the appliance so much. Liquid
fuel burners, on the other hand, dirty the appliance a great
deal, and the boiler controls and maintenance operations
are necessary to ensure a high level of performance and a
long life.
9 Repairs and periodic inspections of the RTT 378-930 boilers
should be carried out by specialised technicians. This man-
ual contains an explanation of the user's responsibilities
and the information required for using the boiler. Beyond
these operations, the boiler should only be commissioned
by the user or by one of our technicians. Do not try to adjust
the boiler or tamper with any components.
9 The mains electrical connections to the boiler room, to the
burner and to the boiler itself, the earthing of the control

5
1.2 General characteristics of the RTT boilers
The RTT 378-930 boilers operate with forced draught burner, they
are made of cast iron elements, provide outputs of 378 to 930
kW when connected to the burner correctly and are available
in 11 different models (from 7 to 16 elements) running on gas or
liquid fuel.
The RTT 378-930 boilers operate at a maximum pressure of 6 bar
and at a maximum temperature of 90 °C.
In the RTT 378-930 boilers, the surfaces that transfer the heat are
expanded by special ns in the burner chamber and in the ue
gas pipes. This system maximises the caloric value of the cast
iron boiler.
The RTT 378-930 boilers are boilers with cast iron elements. This
structure provides for easy assembly and allows you to increase
the capacity of the boiler by simply adding elements. Transport
and installation are simplied by the fact that the boiler is as-
sembled on site. Handling or changing its position are easy and
do not require the breaking of walls, etc.
The RTT 378-930 boilers have been produced with a special iron
alloy EN GJL 200, which provides a high degree of resistance to
corrosion and thermal expansion. This special material guaran-
tees the boilers have a long working life.
Thanks to the special horizontal gas elements with three pas-
sages, the combustion gases pass three times in the boiler ef-
fectively transferring the thermal energy to the water inside the
elements.
The RTT 378-930 boilers are high performance boilers (max. cal-
oric value 91−93% depending on the fuel used). The high level
of efciency and the perfect insulation translate into greater en-
ergy production with less fuel consumption. The RTT boilers also
provide minimal heat dispersion.
An efcient combustion chamber, a good heat transfer surface,
the turbulators, the manifold and the insulation provide a high
degree of thermal capacity and reduced discharge gas emis-
sions.

6
1.3 Technical data
RTT CAST IRON
BOILER RTT 378 RTT 448 RTT 506 RTT 564 RTT 610 RTT 663 RTT 715 RTT 773 RTT 831 RTT 878 RTT 930 UM
Number of sec-
tions 6 7 8 9 10 11 12 13 14 15 16 pieces
Nominal heat
output
378 448 506 564 610 663 715 773 831 878 930 kW
325000 385000 435000 485000 525000 570000 615000 665000 715000 755000 800000 kCal/h
Nominal heat
input 410 487 551 615 665 720 777 839 900 956 1013 kW
Maximum operat-
ing temperature 90 °C
Temperature ad-
justment range 30-90 °C
Gas side resistor 1.75
2.20
1.90
2.40
2.25
2.75
2.55
3.10
2.80
3.35
3.15
3.70
3.45
4.05
3.80
4.35
4.10
4.75
4.45
4.95
4.85
5.50 mbar
Maximum operat-
ing pressure 6bar
Boiler water ca-
pacity
149.5 174 198.5 223 247.5 272 296.5 321 345.5 370 394.5 litres
0.150 0.174 0.199 0.223 0.248 0.272 0.297 0.321 0.346 0.370 0.395 m2
Diameter ue pipe
tting 350 mm
Com-
bustion
chamber
dimen-
sions
width X
length 501 mm
L910 1,070 1,230 1,390 1,550 1,710 1,870 2,030 2,190 2,350 2,510 mm
Water input-out-
put coupling G4 DN (*)
Boiler gas volume 341.74 400.71 459.68 518.65 577.62 636.59 695.56 754.53 813.5 872.47 931.44 dm3
(lt.)
0.342 0.401 0.460 0.519 0.578 0.637 0.696 0.755 0.814 0.872 0.931 m2
Combustion
chamber gas vol-
ume (gas side)
179.39 210.93 242.48 274.02 305.56 337.1 368.64 400.18 431.73 463.27 494.81 dm3
(lt.)
0.179 0.211 0.242 0.274 0.306 0.337 0.369 0.400 0.432 0.463 0.496 m2
Safety limit ther-
mostat 110 °C
Type of fuel
I2Hgas
Extra light fuel oil comb.
liquid
Flue gas-
es output
tempera-
ture
full
load 182-187 178-
185
175-
180 173-178 173-176 170-175 170-174 168-172 165-168 162-165 160-163 °C
partial
load 165-172 164-170 162-168 161-165 160-165 158-163 156-161 155-160 155-160 153-150 150-148 °C
Mass ow
of the
ue gases
full
load 633 750 848 945 1,023 1,110 1,198 1,295 1,393 1,470 1,588 kg/h
partial
load 380 450 508 567 614 666 719 777 836 882 935 kg/h
Boiler
dimen-
sions
width X
length 840 X 1355 mm
L1,300 1,460 1,620 1,780 1,940 2,100 2,260 2,420 2,580 2,740 2,900 mm
Heat loss in stand-
by
0.33 0.31 0.28 0.27 0.24 0.22 0.20 0.18 0.17 0.16 0.14 %
11583 12890 13154 14143 13608 13543 13284 12928 13127 13046 12096 kCal/h
Diameter burner
hole 225 mm
Type of burner With short head
Flue effect 5Pa
Boiler net weight 1,020 1,235 1,415 1,555 1,725 1,875 1,975 2,170 2,375 2,465 2,540 kg

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1.4 Boiler data plate
The data plate is applied to the rear of the boiler shell.
1.5 Overall dimensions
592
840
1355
L
MODEL LENGTH L (mm)
RTT 378 1,300
RTT 448 1,460
RTT 506 1,620
RTT 564 1,780
RTT 610 1,940
RTT 663 2,100
RTT 715 2,260
RTT 773 2,420
RTT 831 2,580
RTT 878 2,740
RTT 930 2,900
592
1134
250
1.6 Delivery
The boiler elements are not supplied assembled, according to
the characteristics specied and the dimensions of the instal-
lation room. The supply of the disassembled boiler provides for
the shipping of the elements and the assembly equipment on
pallets. The outer casing, the insulation and other components
are supplied inside a box. The assembly of the boiler is carried
out by technicians.
Burner box (pallet and
cardboard box)
Casing walls and insulat-
ing covering (wood box)
Cast iron boiler elements
(pallet 80x120)
Box for assembly pieces
(cardboard box)
Control panel box (card-
board box)
9 Comply with the meaning of the symbols on the packaging
for reasons of safety.

8
1.7 Installation of the boiler
The dimensions of the boiler room and the free spaces should
make it easy to carry out any assembly work, repairs, re-assem-
bly and connection of the burner.
900 mm
A + 200
(min.
1000 mm)
A + 200
(min.
1000 mm)
The recommended height for the boiler room is at least 2,200
mm, leave the minimum space free on the sides and in front of
the boiler as shown in the drawing. Provide a base with a min-
imum height of 200 mm above the oor for the installation of
the burner of the boiler.
MODEL LENGTH L (mm)
RTT 378 1,300
RTT 448 1,460
RTT 506 1,620
RTT 564 1,780
RTT 610 1,940
RTT 663 2,100
RTT 715 2,260
RTT 773 2,420
RTT 831 2,580
RTT 878 2,740
RTT 930 2,900
1000 mm
200 mm
L -200 mm
L
A
Characteristics of the base:
−The concrete base should have the indicated dimensions.
−The concrete base should not be covered with a slippery
material like ceramic etc.
−Any acoustic insulation should be made before the base.
−The base should be made of BS 25 ber concrete.
0 Do not place ammable materials on the boiler or at a dis-
tance less than the specied safety distance.In the RTT boil-
ers the door of the burner can open from both sides. For
this reason, equal free distances are specied on both sides
(min. 700 mm). This characteristic is advantageous for oper-
ations to be carried out on the boiler. If the space available
in the boiler room is not sufcient for the distances indicat-
ed, you can choose the opening side and leave more space
free on that part. On the other part, half the indicated free
distance is sufcient.
Provide enough space for the tools to be used in the boiler room.

9
1.8 Important information about the boiler room
9 The boiler room should be well lit and the light switches
should be located outside the room itself.
9 Place any gas detection devices at a height conforming to
regulations in force.
9 Do not place devices like the water pump, the contactor,
etc., in the boiler room.
9 Repair or replace as soon as possible any electric locks, ca-
bles, etc., that could cause short-circuits.
9 Before carrying out any welding in the boiler room, switch
off the boiler and stop the ow of ue gases by closing the
gas valve.
9 Inside the boiler room there should be no explosive, com-
bustible or inammable material.
9 The boiler room air should not contain any explosive, com-
bustible or inammable gas.
9 Children or non-technical persons should not be allowed
in the boiler room, just the person who is responsible for it.
Keep a copy of the key for the boiler room in a safe place for
emergencies.
9 It is possible to insulate the boiler room against noise and
heat, also the position and the orientation of the boiler are
important for its acoustic insulation.
9 Place the fuel tanks in another room surrounded by walls
and with adequate natural ventilation.
9 Arrange for the creation of a diversion of the water supply
line near the boiler and a drainage system for draining the
boiler water.
9 It is strongly recommended not to install extraction systems,
air conditioning system or other devices that in the boil-
er room, as a secondary effect, could cause the so-called
"vacuum effect" and reduce the draught force of the boiler,
with main consequence of damaging the burner.
9 Make sure that the boiler room receives sufcient air either
naturally or forced (using an aspirator).
9 To ensure the burner and the boiler work efciently keep the
boiler room clean and prevent the formation of humidity.
9 The boiler room should have the minimum dimensions
specied.
9 Do not store inammable material inside the room.
9 Do not touch the supply pipe tting or other hot parts of the
boiler when it is running.
9 Do not install the boiler on a rubber mat.
9 When using LPG or another liquid fuel, the boiler room,
the fuel, the system components and the hydraulic pipes
need to be in conformity with the parameters established
by European standards and by gas supplying companies.
The company is not responsible for any faults or problems
caused by inadequate or insufciently adequate conditions
for the boiler room, the hydraulic pipes and the other com-
ponents of the system.
9 Follow the instructions of your local gas suppliers.

10
1.9 Hydraulic system
Limescale and other chemical substances in the water can so-
lidify producing incrustations. To prevent this happening, equip
the system with a closed expansion tank. The water that en-
ters the closed expansion tank does not evaporate and is not
dispersed. In this way the level of water in the system is kept
constant and it will not be necessary to add fresh water. In ad-
dition, limescale and dust do not form and the system will have
a longer life.
−The water contained in the radiator and in the heating
system cannot be drunk and is not suitable for domestic
use. Do not take water from the system. Add water if the
level is low.
−The hardness level of the water should be low to prevent
the formation of limescale and other chemical powders.
Quality of the water circuit water: Ph ≥7.2 Th ≤25 °Fr
−If the water from the mains is not of the required quali-
ty, after appropriate analyses it is possible to add spring
water or water from other sources. If necessary, the water
can be treated to get the desired quality.
−To prevent limescale or other powders penetrating the
boiler, or from the boiler going into the water circuit, dust
lters need to be installed at the system's input and out-
put.
−Connect the recirculation pump to the boiler output. The
power of the pump should be suitable for the boiler. Oth-
erwise, the water ow and the boiler performance may
suffer.
−To raise the temperature of the return water and to en-
sure the system runs properly, use a 4-way mixing valve
or a by-pass pump with thermostatic control.
−Connecting a 3-way motor valve between the supply line
and the return line of the heating system you can obtain
a calibrated control of the water ow towards the system.
−There must always be water in the boiler. Otherwise the
pipes and the boiler could corrode. If the boiler is not
used in winter, add an anti-freeze solution to prevent
water freezing inside the system.
REFERENCE VALUES
pH less than 7.2
Electrical conductivity less than 200 μs/cm (25°C)
Chloride ions less than 50 ppm
Sulphuric acid ions less than 50 ppm
Total iron less than 0.3 ppm
M alkalinity less than 50 ppm
Total hardness less than 25° F
Sulphur ions none
Ammonia ions none
Silicon ions less than 30 ppm
The Thermostat (1) should be installed at a distance of 3-5 diam-
eters from the connection point to the return line.
D
1
3÷5 D
3
22
3
33
4
5
3
8
10 15
10
13
14
12
1
EAF
EAF
15
6
33
33
11
67
17 5
33
3
5
3
4
3
5
3
4
SYSTEM
OUTLET
SYSTEM
RETURN
LINE
DOMESTIC
WATER
UTILITIES
DISCHARGES DISCHARGES
1 Boiler
2 System manifolds
3 Shut-off valves
4 System pumps
5 Non-return valves
6 Automatic vent valve
7 Boiler safety valve
8 Boiler discharge tap
9 Storage heater safety valve
10 Charging the system
11 System expansion tank
12 Storage heater
13 Storage heater discharge tap
14 Domestic hot water expansion
tank
15 Softener filter
16 Pressure reducer
17 Condensation pump
1.10 Schematic diagram - system for heating and domestic hot water production

11
1.11 Important instructions for the connection of the fuel tank
1.12 Important information about the ue gases pipe
They base of the fuel tank should be strong enough to bear the
weight of the tank. If the tank is on the outside, the connec-
tion pipes must be insulated. The fuel tank should be positioned
higher than the burner.
1 Fuel tank
2 Air pipe
3 Filling unit
4 Drain valve pipe
5 Drain valve
6 Level indicator
7 Heater
8 Fuel suction line
9 Cut-off valve
10 Heater filter
H910
8
7
1
2
4
5
6
3
The difference in height between the burner and the fuel tank
(H) should be greater than 4 m. In the seasons when the boiler is
not used the tank should be emptied to avoid corrosion.
Low flue edge
Bad surface,dust etc.. Blocking gas flo
w
Dust obstacling cleaning
Flue which is not available for cleaning
Weakly closed door
Too long pipe
Cleaning door leaking air
Objects blocking gas flow
Connection betwee two flue lines
Another boiler on same flue
Cracks
Humidity
Flue without ridge
Thick section 1
Flue must be isolated. Isolation ratio is: ∆t< 1°C/m
Minimun flue highth must be 6 m.
Horizontal flue channels must be connected with at least %5 slope
and length of them will not pass 1/4 of the lenght of the flue.
The gas flow speed must not come under 0,5 m/sec. limit. (2 m/sec.
in the advised speed)

12
1.14 High performance cast iron elements
3th pass
(smoke channels)
2nd pass
1st pass
The 3-passage system brings about the forced circulation of the
combustion gas inside the boiler three times before it comes out
of the discharge pipe. In this way, all the useful thermal energy
is transferred to the water inside the elements. The optimised
combustion chamber and the excellent thermal insulation pro-
vide maximum energy efciency.
The combustion chamber of the boiler has a positive pressure.
The boiler operates according to the principle of 3 horizontal
passages.
1.15 Ventilation of the boiler room
The constant ventilation of the boiler room is important for three
reasons:
1 Air is required for the boiler's combustion process.
2 Air is required to prevent the formation of dirt and dust and
for the emission of the gases and the depletion of the fuel.
3 Air is required to prevent the boiler room overheating.
Ventilation for the rst two reasons is constantly required. In the
third case, ventilation is needed above all for boilers that also
operate in summer.
The maximum temperature of the boiler room should be 32 °C
and the room should be protected from frost.
Type of boiler Combustion gas pipe
dimensions (mm)
Flue gases
pipe
(methane gas) (m)
RTT 378 350 11.41
16.43
RTT 448 350 16.01
23.06
RTT 506 350 20.44
29.44
RTT 564 350 25.41
36.59
RTT 610 350 29.78
42.88
RTT 663 350 35.1
50.54
RTT 715 350 40.86
58.84
RTT 773 350 47.7 7
68.79
RTT 831 350 55.23
79.53
RTT 878 350 61.58
88.68
1.13 Control panels that can be combined
The control panels that can be combined with the RTT boilers are
those shown below, which take into account the various oper-
ating functions, the requirements of the heating system and the
various devices used on it.
TECH PRIME only for heating (1 direct zone) with one-stage or two
stage burner.
TECH PRIME ACS only for heating (1 direct zone) and domestic hot
water production with one-stage or two stage burner.
9 When the TECH PRIME control panel is installed, on the boiler
return line (cold water), there needs to be a well for housing
the probe. For the accessories codes, see the price list.
9 The boilers in the RTT range have a maximum operating
temperature of 110°C.
9 Before placing the electrical panel on the top panel it is nec-
essary to t the relative shim supplied with the boiler. For
more details, see the assembly manual.

13
Type of boiler Combustion gas pipe
dimensions (mm)
Flue gases
pipe
(methane gas) (m)
RTT 930 350 69.14
99.56
If the fuel is methane gas:
Type of
boiler
(*) Cross-section of the
opening for natural ven-
tilation (cm²)
(**) Volume of air
required for forced
ventilation
*** Lower part Upper
part
Lower
part
Upper
part
RTT 378 1,971 985 1,224 816
RTT 448 2,285 1,142 1,450 967
RTT 506 2,546 1,273 1,639 1,093
RTT 564 2,808 1,404 1,827 1,218
RTT 610 3,017 1,509 1,978 1,319
RTT 663 3,253 1,626 2,147 1,432
RTT 715 3,488 1,744 2,317 1,545
RTT 773 3,750 1,875 2,505 1,670
RTT 831 4,011 2,006 2,694 1,796
RTT 878 4,221 2,110 2,844 1,896
RTT 930 4,456 2,228 3,014 2,009
(*) If natural ventilation is used.
(**) If forced ventilation is used.
(***) The value in the “Lower” column refers to the clean air in-
put, the one in the “Upper” column to the air output.
To ensure the boiler is operating at optimal conditions, the tem-
perature difference between the supply water and the return
water should be no greater than 20 °C. The boiler should not be
started or run with water volumes lower than those indicated in
the following table.
Type of
boiler
Output ∆t = 15 K (*) ∆t = 20 K (*)
kCal/h kW
Water
ow
rate
Water
resist-
ance
Water
ow
rate
Water
resist-
ance
m3/h mbar m3/h mbar
RTT 378 325,000 37 7.9 21.67 102 16.25 54
RTT 448 385,000 4 47.7 25.67 147 19.25 80
RTT 506 435,000 505.8 29.00 180 21.75 105
RTT 564 485,000 564.0 32.33 160 24.25 78
RTT 610 525,000 610.5 35.00 175 26.25 88
RTT 663 570,000 662.8 38.00 200 28.50 115
RTT 715 615,000 715.1 41.00 220 30.75 130
RTT 773 665,000 773.3 44.33 160 33.25 85
RTT 831 715,000 831.4 47.67 180 35.75 90
RTT 878 755,000 87 7. 9 50.33 205 37.75 125
RTT 930 800,000 930.2 53.33 220 40.00 140
(*) ∆t = temperature difference
NOTA:
The RTT boiler has been designed only for heating systems
with forced circulation of hot water.
1.16 Gas side resistor and output temperature of
combustion gases
0,30
100 200 300 400 500 600 700 800 900
1,20
2,10
2,70
3,30
4,50
5,10
5,70
3,90
Heat output (kW)
Gas side resistance (mbar
)
Full load
Part load
100
130
180
200
220
160
10 20 30 40 50 60 70 80 90 100
Exit flue gas temperature (°C)
Load (%)
1.17 User instructions
Heating system
The difference in temperature between the supply temperature
and the water return temperature should not exceed 20°C. The
temperature of the return water should higher than 50-55 °C.
Use the boiler's protection pump to raise the temperature of
the return line water. The water level in the system should be
measured every day (if the circuit is open with a water gauge, if
closed with a pressure gauge) topping up with water if the level
is too low. Do not add water when the system is hot. If there are
problems that are causing leaks, these should be dealt with as
soon as possible. The water circuit should be made by certied
professionals, in conformity with the requirements and using
the materials specied in current regulations.
Connections to the electrical system and fuel delivery system
These connections should be made by certied professionals, in
conformity with the requirements and using the materials spec-
ied in current regulations. Burner, control panel, Ecopanel etc.:
read the warnings and the instruction manuals provided by the
manufacturer of by the distributor. The burner should not start
before the boiler's recirculation pump is running. If there is a
fault with the recirculation or protection pump, switch off the
burner. The operation of the systems should be coordinated. Do
not switch on the pumps when the water temperature is at 40
°C or higher. The recirculation pump and the burner should op-
erate contemporaneously.
The protection pump should be chosen taking into account the
boiler capacity. The connection of the pumps to the manifolds
should be carried out correctly with valve and thermostat. In this
way the system will stop at the temperature that has been set. If

14
there is any anomaly or fault (contactor, thermal fault, electrical
supply interruption etc.), if the pumps are not running (heating,
protection pumps etc.), the burner should not start. The lock-
out should occur automatically. The electrical system should be
made taking into account the above information.
1.18 Conveyance and discharge of the boiler
water
Discharge of the boiler water
To empty the boiler, open all the valves of the circuit and the ra-
diators. The water of the entire system can be drained by emp-
tying the boiler as the end element of the system. If some parts
of the heating system are under the boiler room, draining the
water can be carried out at the lowest point of the system.
Supplying the boiler with water
The boiler receives water from the tap through the water circuit.
During the conveyance process, all the water circuit and radiator
valves need to be open. To prevent air entering the system, this
operation should be carried out slowly and by opening the top
tap. When water comes out of this tap, the operation is nished.
Let the air come out of each radiator. The water should be of the
quality indicated in the chapter "Hydraulic system" a pagina 10.
The boiler should not be lled with water when it is hot, since
this could cause cracks in the elements.
1.19 Instructions for disposing of the product
Cast iron boilers have a long life due to the particular character-
istics of the construction materials used. The service life of these
appliances, which is declared in the accompanying legal doc-
uments, is 15 years. Therefore, the replacement of these appli-
ances generally takes place for reasons of plant modernisation.
Cast iron boilers, produced with innocuous materials, can be
disposed of as follows:
Cast iron body (Grey cast Iron)
Using disposal companies
specialised in iron and cast
iron foundries
Casing piping and panels Using disposal companies
specialised in iron
Other Metal Parts Using disposal companies
specialised in iron
Thermal ceramic and other
insulating materials
Using normal refuse dis-
posal services
NOTA:
For more information please contact an authorised deal-
er
1.20 Fire prevention regulations for the boiler
room
The boilers should be positioned and installed particularly care-
fully and in conformity with re safety regulations.
When installing and using the boiler, a safety distance of 200
mm must be observed from class B, C1 and C2 ammable ma-
terials.
For class C3 materials that easily catch re, namely materials that
burn quickly and that keep combusting even after removal from
the source of the ignition, the safety distance is 400 mm.
The safety distance should be doubled also when the amma-
bility class of the material has not been ascertained.
Flammability classes of the
materials and the construc-
tion products
Materials and construction
products
A - Non-combustible
Granite, sandstone, bricks,
ceramic tiles, mortar, re-
proof plasters etc.
B - Almost non-combustible
acumin, izumin, heraklit,
lignos, basalt panels and
bre, berglass panels etc.
C1- Difcult to ignite Beech or oak, hobrex panels,
plywood, werzalit etc.
C2 - Normal combustibility
Pine, larch, white wood,
panels of wood shavings and
cork, rubber oors etc.
C3 - Easily ignited
Tar-coated sheets, polyure-
thane, polystyrene, polyethyl-
ene, PVC etc.
NOTA:
For more information, contact an authorised service
company.
1.21 Boiler checks and start-up
Preliminary checks
−The following checks need to be carried out before start-
ing the boiler. In the event of problems or faults, the boil-
er should not be started.
−Check the level of the boiler water. Add water if the level
is low.
−Call for technicians if you see water leaks. Leaks should be
dealt with before starting the boiler. If there are leaks in
the water circuit, the boiler should be started after carry-
ing out the necessary repairs.
−Check the connections of the ue gas pipe. If there are
problems, the boiler should be started after carrying out
the necessary repairs.
−The room should have an adequate ventilation system.
−If the boiler runs on gas, check the gas valves have been
installed correctly.
−If the boiler runs on liquid fuel, check the level of fuel
in the tank and open the fuel valve. Check the connec-
tion between the fuel supply and the burner. If there are
problems, clean the lters.
−Check the pumps are running and check their rotation
direction.
−Check the electrical connections of the control panel.
−All the boiler's gas and water valves should be open.
9 Check all the other connections according to the system's
options.
Boiler start-up
−Switch on the electrical supply using the master switch in
the boiler room. The operating lamp comes on.
−Start the recirculation pump.
−Set the burner's ignition switch to “ON” (see burner's in-
struction manual). The lamp comes on.
−Adjust the temperature of the boiler with the thermostat.
If it is a two-stage burner, adjust the boiler temperature
as for the single-stage burner. The two-stage thermostat
(TRZ) adjusts the temperature (8 °C).
−If the burner does not start, follow the instructions in the
burner's manual. If it is not possible to start the burn-
er after following the manual's instructions, contact the
burner's technical assistance service.
Switching off the boiler
−Switch off the burner (carrying out the commands de-
scribed in the burner's instruction manual).
−Set the “ON/OFF” switch on the control panel to “OFF”.
−Switch off the circulation pump
−Close all the fuel valves.
−Switch off the electrical supply using the master switch in

15
the boiler room.
First checks in the event of a fault
When the burner or a boiler has a fault, check the following be-
fore calling for assistance. Do not carry out any other interven-
tion except for the controls indicated. After these checks, contact
the technical assistance service.
If the boiler stops and does not restart, the stop could have been
caused by the safety thermostat due to the overheating of the
water in the boiler. In this case, wait for the boiler to cool down
and carry out the following checks.
−Check that the fuel is being correctly supplied to the
burner. If necessary, restore the fuel supply to the burner.
−Check that the pump is working. If the pump has stopped
it could be the cause of the overheating. Contact the
pump's manufacturer or distributor.
−Check the position of the valves. If the valves are closed,
open them. Press the switch of the safety thermostat
when the boiler has cooled down enough.
−The burner should start.
−If the boiler does not start, or if the safety thermostat
stops the boiler again, contact the technical assistance
service.
−If the warning light of the burner is on, consult the burn-
er's instruction manual or contact the appliance's man-
ufacturer or dealer.
1.22 Maintenance instructions
The boiler and burner checks are carried out: daily (daily use),
periodically and annually.
Daily checks
The user should carry out these checks daily in the season when
the boiler is used every day. Read and follow the instructions
for the daily checks in the chapter “Preliminary checks” in the
manual.
Periodic checks
To perform efciently, to prevent faults and to prolong the boil-
er's life, it is important to carry out periodic checks. We recom-
mend these checks be carried out once every three months. Pe-
riodic checks are carried out by the technicians as follows:
−Checking and cleaning, if necessary, of the combustion
chamber and the passageways of the boiler smoke.
−Checking for water leaks going into and coming out of the
boiler and checking the ue gases pipe tting seal.
−Checking the valves.
−Checking the pumps.
−Checking and cleaning, if necessary, the fuel lter.
−Checking the combustion (visual). Adjusting the burner
and ame, if necessary.
−Checking and cleaning, if necessary, the liquid fuel sen-
sor.
−Checking the operation and safety of the burner and the
boiler.
Annual checks
The annual checks should be carried out by technicians before
the start of the season. The ue gases pipe and the relative t-
tings need to be cleaned before requesting the intervention of
technicians for the annual checks. In the annual checks, the
technicians assess the following:
−Conditions and sealing of the elements and the insulat-
ing cords.
−Operating pressure for adjusting the combustion with the
combustion gas measurement system, if necessary.
−Sensors and connection of the sensors.
−Boiler combustion chamber and any formations of soot
in the ue gas passages; cleaning after checking.
−Fastening and seal of the boiler door.
−Seals of the boiler ttings.
−Correct opening and closing of the valves.
−Fuel lter and eventual cleaning.
−Burner liquid sensor with cleaning or replacement.
−Operation and safety of the burner and the boiler.
1.23 Cleaning the boiler
Before carrying out this work on the boiler, switch off the electri-
cal supply with the master switch, close the fuel valves and pro-
tect the control panel and the burner so as not to damage them.
Cleaning the ue gas passages
The formation of soot on the heating surfaces can lead to an
increase in the temperature of the fumes by up to 100° above
normal, leading to a yield reduction of 5%.
−Remove the M16 screws and the nuts from the four hinges
that connect the burner door to the front and then open
the door.
−Clean the combustion chamber, extract the turbulators
and the horizontal ue gas passages (second and third
passage).
−Clean the turbulators and put them back in the channels.
−Close the door of the burner securely.
−During this cleaning operation, a layer of soot could form
in the ue gas outlet zone. The soot can be removed by
separating the horizontal passages from the ue pipe.
−After this operation, put back the screws and check the
door seal.
The frequency of the cleaning changes depending on the type of
fuel used by the boiler and the period it is used. When cleaning
the boiler, check the ceramic bre cords that insulate the door
from the front element and the ue gases pipe from the rear
element and replace them if necessary.

16
1.24 Burner door and burner connection
When assembling the burner, be careful not to leave any empty
space between the front door and the body of the burner. All the
points of contact should be covered with insulating material to
prevent air leaks.
To make it easier to x the burner to the door a metal ange is
used. The cover measures 320x320 mm and has a thickness of 10
mm; the burner hole measures 225 mm (1).
The burner door insulation (2) is composed of a special thermal
ceramic that can withstand up to 1250 ºC and is safe for people
to use. Be very careful when transporting the insulating plate.
A ceramic bre insulating cord is inserted in the door groove. The
cord has the function of preventing leaks between the door and
the front element of the boiler. After cleaning or repair work, put
back the door xing it solidly to the front element.
In the RTT 378-930 boilers it is possible to choose the opening
side of the door. This feature is an advantage for assembly, repair
operations etc.
The burner door has an inspection window made of tempered
ceramic glass (3).
45°
2
3
1

17
OIL BURNER
BOILER BURNER
MODEL CODE
RTT 378 RL 44 MZ TC 3470310 (*)
3470340 (**)
RTT 448 RL 50 t.c. 3474632 (**)
RTT 506 RL 50 t.c. 3474632 (**)
RTT 564 RL 70 t.c. 3475032 (**)
RTT 610 RL 70 t.c. 3475032 (**)
RTT 663 RL 70 t.c. 3475032 (**)
RTT 715 RL 70 t.c. 3475032 (**)
RTT 773 RL 100 t.c. 3475232 (**)
RTT 831 RL 100 t.c. 3475232 (**)
RTT 878 RL 100 t.c. 3475232 (**)
RTT 930 RL 100 t.c. 3475232 (**)
DOUBLE FUEL BURNER
BOILER BURNER
MODEL CODE
RTT 378 RLS 38 3484101 (*)
RTT 448 RLS 50 3484601 (**)
RTT 506 RLS 70 3485001 (**)
RTT 564 RLS 70 3485001 (**)
RTT 610 RLS 70 3485001 (**)
RTT 663 RLS 70 3485001 (**)
RTT 715 RLS 70 3485001 (**)
RTT 773 RLS 100 3485201 (**)
RTT 831 RLS 100 3485201 (**)
RTT 878 RLS 100 3485201 (**)
RTT 930 RLS 100 3485201 (**)
GAS BURNER
BOILER BURNER
MODEL CODE
RTT 378 RL 44 MZ TC 3789110 (*)
3789140 (**)
RTT 448 RS 50 t.c. 3784702 (**)
RTT 506 RS 50 t.c. 3784702 (**)
RTT 564 RS 64 MZ TC 3789310 (**)
RTT 610 RS 64 MZ t.c. 3789310 (**)
RTT 663 RS 70 t.c. 3785102 (**)
RTT 715 RS 70 t.c. 3785102 (**)
RTT 773 RS 100 t.c. 3785302 (**)
RTT 831 RS 100 t.c. 3785302 (**)
RTT 878 RS 100 t.c. 3785302 (**)
RTT 930 RS 100 t.c. 3785302 (**)
(*) Single-phase burner
(**) Three-phase burner
1.25 Table of burner combinations

18
1.26 Transport and storage
The manufacturer transports the boiler on a pallet xing it (using
screws) to prevent any sliding. Transport the boiler only on its
base and in no other way.
When the boiler is being stored or transported ensure at least
the normal storage conditions (non-aggressive environment,
air humidity less than 75%, temperature between 5° and 55° C,
low dust levels and the prevention of damage due to biological
factors).
Do not force the cover elements and the boiler panels in the
storage phase or when being transported.
For the transportation of the boiler always use lift trucks, trans-
pallets or other means of transport with wheels.

19
1.27 Useful information
Retailer: ...........................................................................
Mr.: ..................................................................................
Address: ...........................................................................
Tel.:..................................................................................
Technical Assistance Centre: ...............................................
Mr.: ..................................................................................
Address: ...........................................................................
Tel.:..................................................................................
Installer:...........................................................................
Mr.: ..................................................................................
Address: ...........................................................................
Tel.:..................................................................................
Date Intervention
Fuel supplier:....................................................................
Mr.: ..................................................................................
Address: ...........................................................................
Tel.:..................................................................................
Date Qty supplied Date Qty supplied Date Qty supplied Date Qty supplied

RIELLO S.p.A.
37045 Legnago (VR)
Tel. [phone] - Fax [phone] - www.riello.it
As part of the company’s ongoing commitment to perfecting its range of products, the appearance, dimensions, technical data,
equipment and accessories may be subject to variation.