Robur M20 Service manual

M
Gas unit heaters for use in industrial and commercial
installations
Powered by natural gas/LPG
Installation, use and maintenance manual

Revision: G
Code: D-LBR153
This Installation, use and maintenance manual has been drawn up and printed by Robur S.p.A.; whole or partial
reproduction of this Installation, use and maintenance manual is prohibited.
The original is led at Robur S.p.A.
Any use of this Installation, use and maintenance manual other than for personal consultation must be previously
authorised by Robur S.p.A.
The rights of those who have legitimately led the registered trademarks contained within this publication are not
aected.
With the aim of continuously improving the quality of its products, Robur S.p.A. reserves the right to modify the
data and contents of this Installation, use and maintenance manual without prior notice.
DISPOSAL
The appliance and all its accessories must be disposed of separately in accordance with the regulations in force.
Use of the WEEE symbol (Waste Electrical and Electronic Equipment) indicates that this product cannot be disposed of as house-
hold waste. Proper disposal of this product helps to prevent potential negative consequences for the environment and human
health.

Installation, use and maintenance manual – M gas unit heater 3
INDEX OF CONTENTS
I Introduction.......................................................................... p.4
I.1 Recipients................................................................ p.4
I.2 Control device ....................................................... p.4
II Symbols and denitions......................................... p.4
II.1 Key to symbols ...................................................... p.4
II.2 Terms and denitions ......................................... p.4
III Warnings ................................................................................... p.4
III.1 General and safety warnings............................ p.4
III.2 Conformity.............................................................. p.6
III.3 Exclusions of liability and warranty ............... p.6
1 Features and technical data................................ p.7
1.1 Features.................................................................... p.7
1.2 Dimensions............................................................. p.8
1.3 Electrical wiring diagram................................... p.9
1.4 Controls.................................................................. p.11
1.5 Electrical panel .................................................... p.14
1.6 Technical data...................................................... p.14
2 Transport and positioning.................................. p.15
2.1 Warnings................................................................ p.15
2.2 Handling................................................................ p.16
2.3 Appliance positioning ...................................... p.16
2.4 Minimum clearance distances....................... p.16
2.5 Support bracket.................................................. p.17
3 Heating engineer........................................................... p.18
3.1 Warnings................................................................ p.18
3.2 Fuel gas supply.................................................... p.18
3.3 Combustion products exhaust...................... p.19
3.4 Air ducting ............................................................ p.22
4 Electrical installer ......................................................... p.23
4.1 Warnings................................................................ p.23
4.2 Electrical systems ............................................... p.23
4.3 Electrical power supply.................................... p.23
4.4 Control system..................................................... p.24
5 First start-up ....................................................................... p.27
5.1 Preliminary checks............................................. p.27
5.2 Burner pressure adjustment........................... p.27
5.3 Gas changeover .................................................. p.29
6 Normal operation ......................................................... p.30
6.1 Warnings................................................................ p.30
6.2 Switch on and o................................................ p.30
7 Maintenance....................................................................... p.31
7.1 Warnings................................................................ p.31
7.2 Scheduled routine maintenance.................. p.32
7.3 Resetting the temperature limit
thermostat ............................................................ p.32
7.4 Periods of inactivity........................................... p.32
7.5 Troubleshooting ................................................. p.32

Introduction
4
I
I INTRODUCTION
Installation, use and maintenance manual
This Manual is an integral part of the M unit and
must be handed to the end user together with the
appliance.
I.1 RECIPIENTS
This Manual is intended for:
▶ End user, for appropriate and safe use of the appliance.
▶ Qualied installer, for correct appliance installation.
▶ Planner, for specic information on the appliance.
I.2 CONTROL DEVICE
In order to work, the M unit requires a control device to
be connected by the installer (see Paragraph 1.4 p.11 ).
II SYMBOLS AND DEFINITIONS
II.1 KEY TO SYMBOLS
DANGER
WARNING
NOTE
PROCEDURE
REFERENCE (to other document)
II.2 TERMS AND DEFINITIONS
Appliance / Unit = equivalent terms, both used to refer to
the gas unit heater.
TAC = Technical Assistance Centre authorised by Robur.
External request = generic control device (e.g. thermo-
stat, timer or any other system) equipped with a volt-
age-free NO contact and used as control to start/stop the
unit.
Chronothermostat = control device that integrates the
functions of room thermostat and clock programmer.
First start-up = appliance commissioning operation
which may only and exclusively be carried out by a TAC.
III WARNINGS
III.1 GENERAL AND SAFETY WARNINGS
Installer's qualications
Installation must exclusively be performed by a
qualied rm and by skilled personnel, with spe-
cic knowledge on heating, electrical systems and
gas appliances, in compliance with the laws in
force in the Country of installation.
Declaration of conformity
Upon completing installation, the installing rm
shall issue to the owner/client the appliance's
workmanlike conformity declaration, according to
national/local regulations in force and the manu-
facturer's instructions/provisions.
Misuse
The appliance must only be used for the purpos-
es for which it has been designed. Any other use is
deemed hazardous. Incorrect use may aect oper-
ation, duration and safety of the appliance. Adhere
to the manufacturer's instructions.
Use of the appliance by children
The device can be used by children over 8 years
old, and by people with reduced physical, senso-
ry or mental capabilities, or lack of experience or
knowledge, only if they are under surveillance or
after they have received instructions regarding
safe use of the appliance and understanding the
dangers inherent in it. Children should not play
with the appliance.
Hazardous situations
Do not start the appliance in hazardous conditions,
such as: gas smell, problems with the electrical/gas
system, parts of the appliance under water or dam-
aged, malfunctioning, disabling or bypassing con-
trol and safety devices.
In case of danger, request intervention by qualied
personnel.
In case of danger, switch o the electrical power
and gas supplies only if this can be done in total
safety.
Do not entrust children, persons with physical,
sensory or mental disabilities or persons with
poor knowledge and experience with use of the

Warnings
Installation, use and maintenance manual – M gas unit heater 5
III
appliance.
Gas component tightness
Before performing any operation on gas ducting
components, close the gas valve.
Upon completing any procedure, perform the
tightness test according to regulations in force.
Gas smell
If you smell gas:
Do not use electrical devices such as telephones,
multimeters or other equipment that may cause
sparks next to the appliance.
Shut o the gas supply by turning the valve o.
Open immediately doors and windows to create a
cross-current of air to purify the room.
Switch o the power supply via the external dis-
connect switch in the power supply electrical pan-
el.
Use a telephone away from the appliance to ask for
intervention from qualied personnel.
Poisoning
Ensure the ue gas ducts are tightness and compli-
ant with the regulations in force.
Upon completing any procedure, ensure the tight-
ness of the components.
Moving parts
The appliance contains moving parts.
Do not remove guards during operation, and in
any case prior to disconnecting the power supply.
Burn hazard
The appliance contains very hot parts.
Do not open the appliance and do not touch inter-
nal components before the appliance has cooled
down.
Do not touch the ue gas exhaust before it has
cooled down.
Electrocution hazard
Disconnect the electrical power supply before any
operation on appliance components.
For electrical connections exclusively use compli-
ant components and according to the specica-
tions provided by the manufacturer.
Ensure the appliance cannot be accidentally
switched back on.
Earthing
Electrical safety depends on an eective earthing
system, correctly connected to the appliance and
carried out in accordance with the regulations in
force. Do not use gas pipes to ground electrical
equipment.
Air ow
Do not obstruct the fan intake or the warm air
outlet.
Distance from combustible or ammable mate-
rials
Do not deposit ammable materials (paper, dilu-
ents, paints, etc.) near the appliance.
Comply with current regulations.
Aggressive substances in the air
The air of the installation site must be free from ag-
gressive substances.
Acid ue gas condensate
Discharge the acid condensate of combustion ue
gas, as indicated in Paragraph 3.3.4 p.20 , in com-
pliance with current exhaust regulations.
Switching the appliance o
Disconnecting the power supply while the appli-
ance is running may cause permanent damage to
internal components.
Except in the event of danger, do not disconnect
the power supply to switch o the appliance, but
always and exclusively act through the provided
control device.
In the event of failure
Operations on internal components and repairs
may exclusively be carried out by a TAC, using only
original parts.
In the event of failure of the appliance and/or
breakage of any component, do not attempt to
repair and/or restore and immediately contact the
TAC.
Routine maintenance
Proper maintenance assures the eciency and
good operation of the appliance over time.
Maintenance must be performed according to the
manufacturer's instructions (see Chapter 7 p. 31 )
and in compliance with current regulations.
Appliance maintenance and repairs may only be
entrusted to rms legally authorised to work on
gas appliances and systems.
Enter into a maintenance contract with an author-
ised specialised rm for routine maintenance and
for servicing in case of need.
Use only original parts.
Keep the Manual

Warnings
6
III
This Installation, use and maintenance manual
must always accompany the appliance and must
be handed to the new owner or installer in the
event of sale or removal.
III.2 CONFORMITY
EU directives and standards
The M series gas unit heaters meet the essential require-
ments of the following Directives:
▶ 2014/30/EC "Electromagnetic Compatibility Directive"
as amended and added.
▶ 2014/35/EC "Low Voltage Directive" as amended and
added.
▶ 2006/42/EC "Machine Directive" as amended and add-
ed.
Furthermore, they comply with the requirements of the
following standards:
▶ EN 1020 Non-domestic forced convection gas-red air
heaters for space heating not exceeding a net heat in-
put of 300 kW incorporating a fan to assist transporta-
tion of combustion air or combustion products.
▶ prEN 17082 Domestic and non-domestic gas-red
forced convection air heaters for space heating not ex-
ceeding a net heat input of 300 kW.
Other applicable provisions and standards
The design, installation, operation and maintenance of
the systems shall be carried out in compliance with cur-
rent applicable regulations, depending on the Country
and location, and in accordance with the manufacturer's
instructions. In particular, regulations regarding the fol-
lowing shall be complied with:
▶ Gas systems and equipment.
▶ Electrical systems and equipment.
▶ Heating systems.
▶ Environmental protection and combustion products
exhaust.
▶ Fire safety and prevention.
▶ Any other applicable law, standard and regulation.
III.3 EXCLUSIONS OF LIABILITY AND
WARRANTY
Any contractual or extra-contractual liability of the
manufacturer for any damage caused by incorrect
installation and/or improper use and/or failure to
comply with regulations and with the manufactur-
er's directions/instructions shall be disclaimed.
In particular, the warranty on the appliance may be
rendered void by the following conditions:
Incorrect installation.
Misuse.
Failure to comply with the manufacturer's indica-
tions on installation, use and maintenance.
Alteration or modication of the product or any
part thereof.
Extreme operational conditions or however out-
side of the operational ranges set forth by the man-
ufacturer.
Damages caused by external agents such as salts,
chlorine, sulphur or other chemical substances
present in the air of the installation site.
Abnormal actions transmitted to the appliance by
the system or installation (mechanical stresses,
pressure, vibrations, thermal expansion, electrical
surges...).
Accidental damages or due to force majeure.

Features and technical data
Installation, use and maintenance manual – M gas unit heater 7
1
1 FEATURES AND TECHNICAL DATA
1.1 FEATURES
1.1.1 Available range
M gas unit heater gas unit heaters are available in two
versions:
▶ with horizontal ow, with axial fan (M gas unit heater
series)
▶ with horizontal ow, ductables, with centrifugal fan
(M gas unit heater C series)
1.1.2 Operation
The M series gas unit heater is an independent heating
appliance with airtight combustion circuit and forced air
draft.
It has been designed to be installed inside the room to be
heated.
The combustion circuit is room sealed and meets the re-
quirements for type C appliances: combustion air supply
and ue gas exhaust discharge take place outdoors and
are ensured by the functioning of an extractor fan insert-
ed in the combustion circuit.
The appliance is also approved for type B for installations
where it is allowed to take the combustion air directly
from the room to be heated.
The operation of the gas unit heater is controlled by a con-
trol device (not supplied).
The generator works on/o, on or o, at the heat output
and the ventilation speed of the license plate.
Products of gas combustion (natural gas or LPG) ow in-
ternally through the heat exchangers, which are invested
externally by the air current produced by the fan, deliver-
ing warm air ow into the room.
The fan operates automatically only when it receives the
enabling signal from the fan thermostat, i.e. with hot heat
exchangers, in order to avoid the introduction of cold air
into the room, and it will switch o with cold exchangers.
The air ow direction is adjustable vertically by means of
the revolving louvres of the grille.
A ‘vertical louvres kit’ is also available on request for hori-
zontal regulation of the airow.
If heat exchangers overheat due to malfunction, a temper-
ature limit thermostat cuts o the supply to the gas valve,
thus interrupting fuel ow and turning o the burner.
In case of obstruction of the suction or exhaust duct, or
in case of malfunction of the extractor fan, the dierential
pressure switch intervenes, causing the gas valve to stop
and the heater to switch o.
The winter operation of the gas unit heater can be auto-
matic or manual.
In summer it is possible to operate the fan only in order to
provide a pleasant air ow within the room.
1.1.3 Mechanical components
▶ Stainless steel atmospheric burner.
▶ Flue gas extractor for forced draft of combustion prod-
ucts.
▶ Cylindrical stainless steel combustion chamber.
▶ Robur patented heat exchangers, made out of a spe-
cial aluminium die-cast alloy, with horizontal nning
on the air side and vertical nning on the ue gas ex-
haust side, with a very high heat exchange capacity.
▶ External steel panelling with epoxy powder enamel
nish.
▶ External panels made of stainless steel (available on
request).
▶ Axial fan(s) with high ow rate.
▶ Centrifugal fan (for the M gas unit heater C series).
▶ Flange for duct connection (for series M gas unit heater
C).
▶ Ground control with lock signal and reset button.
1.1.4 Control and safety devices
▶ Electronic control unit, which provides the following
functions:
burner ignition
ame monitoring
▶ 100 °C limit thermostat with manual reset against heat
exchangers overheating.
▶ Thermostat to protect the internal components from
overheating, with manual reset.
▶ Dierential pressure switch.
▶ Fan thermostat.
▶ Gas solenoid valve.

Features and technical data
8
1
1.2 DIMENSIONS
Figure1.1M series generators size
1 Flue gas exhaust
2 Combustion air inlet
3 Power supply cables input
4 Gas connection
H
L
E
G
A
Z
T
S
S
R
N
J
P
X
Y
V
N
T
S
R
J
P
W
4
2
3
X
Y
1
Z
V
F
D
Q
C
B max
4
M20, M25, M30, M35, M36, M40 M50, M60
Figure1.2M C series generators size
1 Flue gas exhaust
2 Combustion air inlet
3 Power supply cables input
4 Gas connection
F
D
B
M
U
Q
C
G
E
A
HL
YX
321
P
J
N
Z
R
S
T
YX
321
R
S
T
Z
V
W
P
J
N
M20 C, M30 C M60 C
V
4
4

Features and technical data
Installation, use and maintenance manual – M gas unit heater 9
1
Table1.1Dimensions
M20 M20 C M25 M30 M30 C M35 /M36 M40 M50 M60 M60 C
A630 630 630 770 770 880 880 1070 1270 1270
B631 947 590 624 988 624 643 590 624 988
C800 800 800 800 800 800 800 800 800 800
D490 490 490 490 490 490 490 490 490 490
E370 370 370 510 510 620 620 810 1010 1010
F405 405 405 405 405 405 405 405 405 405
G440 438 440 580 578 690 690 880 1080 1078
H430 431 430 430 431 430 430 430 430 431
J215 215 215 215 215 215 215 215 215 215
L285 284 285 285 284 285 285 285 285 284
M- 393 - - 393 - - - - 393
N95 95 95 95 95 95 95 95 95 95
P390 390 390 460 460 515 515 398 468 468
Q435 435 435 435 435 435 435 435 435 435
R340 340 340 340 340 340 340 340 340 340
S600 600 600 600 600 600 600 600 600 600
T715 715 715 715 715 715 715 715 715 715
U- 563 - - 580 - - - - 580
V1/2” 1/2” 1/2” 1/2” 1/2” 1/2” 3/4” 3/4” 3/4” 3/4”
W- - - - - - - 432 495 495
X113 113 113 113 113 113 113 113 113 113
Y133 133 133 133 133 133 133 133 133 133
Z355 300 355 410 324 410 410 355 410 324
1.3 ELECTRICAL WIRING DIAGRAM
Figure1.3Operating wiring diagram
CM Fan condenser
CS Extractor fan condenser
L1 Lockout lamp
M Fan motor (2 motors for M50 and M60 models)
M1 Limit thermostat
M10 Internal component protection thermostat
M12 Pressure switch control relay
M2 Fan thermostat
M4 Controller for ignition, adjustment and ame control
M9 Fuse 4,0 A
NP Dierential pressure switch
P1 Reset button
Q1 Gas electrovalve
Q2 Soft opening coil (for M50 and M60 models)
RD Rectier bridge (for M50 and M60 models)
RP7 Ignition electrode
RP8 Detection electrode
S Extractor fan motor
Z1 Summer/winter diverter (not supplied)
Z9 External request (not supplied)
M9 Z1 Z9 M10M1
RP8 RP7
NP
M12
S
CS
M
CM
M
CM
GND
230V-50HZ
M2 L1
Q2
Q1
RD
M12
P1
123 4 5 6 7 13
14 15
16
17
18 19 J6
JT1 J5 JT 2
M4

Features and technical data
10
1
Figure1.4Wiring plan for mounting the M20/M25/M30/M35/M36/M40 devices
(see legend Figure 1.3 p.9 )
BLA Black
BRO Brown
BLU Blue
WIN Winter
SUM Summer
BLA BRO
BLU
WIN
SUM

Features and technical data
Installation, use and maintenance manual – M gas unit heater 11
1
Figure1.5Mounting electrical diagram for M50/M60 units
(see legend Figure 1.3 p.9 )
BLA Black
BRO Brown
BLU Blue
WIN Winter
SUM Summer
6
7
5
1
20
23
24
21
22
230 V - 50 Hz
BLA BRO
BLU
WIN
SUM
1.4 CONTROLS
1.4.1 Control device
The appliance may only work if it is connected to a control
device, selected from:
1. 1 button basic control OCDS012 (supplied)
2. OCTR000 2-key basic control
3. OTRG005 thermoregulator
4. OCDS008 digital chronothermostat (in association
with OTRG005 thermoregulator)
5. OSWR000 Genius software for remote management

Features and technical data
12
1
of gas unit heaters (in association with OTRG005
thermoregulator)
6. External request
1.4.2 OCDS012 1-key basic control
Figure1.6OCDS012 1-key basic control
OCDS012 1-key basic control signals the ame lockout
and allows its resetting.
It does not allow to control the switching on and o of
the unit for space heating, nor for the summer ventilation.
Its functions are:
▶ Light signalling the status of the ame lockout.
▶ Reset of the ame lockout.
For further details and diagrams see Paragraph
4.4.1 p.24 .
1.4.3 OCTR000 2-key basic control
Figure1.7OCTR000 2-key basic control
OCTR000 2-key basic control signals the ame lockout
and allows its resetting. In addition, it allows activating
the summer ventilation mode.
It does not allow to control the switching on and o of the
unit for space heating.
Its functions are:
▶ Light signalling the status of the ame lockout.
▶ Reset of the ame lockout.
▶ Summer ventilation mode activation.
1.4.4 OTRG005 thermoregulator
Figure1.8OTRG005 thermoregulator
The thermoregulator is a device that can directly manage
gas unit heaters: the simple and intuitive display interface
allows the user to change the control parameters, manage
the power on/o and change the operating mode (heat-
ing or summer ventilation); a serial interface also allows
to create cascading systems managed by a single chron-
othermostat (optional OCDS008, described in Paragraph
1.4.5 p. 12 ), with considerable advantages in terms of
temperature control, especially in large spaces.
The main functions are:
▶ Turning the gas unit heater on/o.
▶ Ambient temperature measurement by NTC probe.
▶ Diagnostics.
▶ Reset of the ame lockout.
▶ Gas unit heater data display and parameters setting.
▶ Space heating and summer ventilation setpoint set-
ting.
▶ Summer ventilation mode activation.
▶ Possibility of creating cascaded systems.
▶ Modbus interfacing for remote control.
For further details and diagrams see the OTRG005 tem-
perature controller instruction sheet.
1.4.5 OCDS008 digital chronothermostat
Figure1.9OCDS008 digital chronothermostat
OCDS008 digital chronothermostat integrates the func-
tions of room temperature control and remote control of
the gas unit heaters heating system in a single interface,
specically designed to make all functions available to the
user in a clear and intuitive way.
It may be used only in association with the OTRG005
thermoregulator.
The remote control of the heating system allows man-
aging the operational parameters of more than one gas
unit heater with the relative control boards connected in

Features and technical data
Installation, use and maintenance manual – M gas unit heater 13
1
cascade and also resetting any locking.
The weekly programming includes 3 adjustable tempera-
ture levels and daily times slots.
The main functions are:
▶ Multilingual interface.
▶ Gas unit heaters cascade system management (up to
10).
▶ Hourly programming on a weekly basis on 3 temper-
ature levels.
▶ Diagnostics.
▶ Reset.
▶ Gas unit heater data display and parameters setting.
▶ Space heating and summer ventilation setpoint set-
ting.
▶ Summer ventilation mode activation.
For further details and diagrams see the instruction sheet
of the digital chronothermostat OCDS008.
1.4.6 OSWR000 Genius software for remote
management of gas unit heaters
This is a software that allows, through the OTRG005 ther-
moregulators, to centralize the management of up to
100 gas unit heaters, allowing them to be freely divid-
ed into zones, for an even more personalized heating
management.
If the PC on which the software is installed is accessible
remotely, the software allows remote management of
the whole heating system from multiple devices, as well
as sending emails to report any anomalies to the gas unit
heaters or to the heating system.
The main functions are:
▶ Centralized system to control up to 100 gas unit heat-
ers.
▶ Division of gas unit heaters into zones, up to 10
dierent zones.
▶ Independent or centralized gas unit heaters control.
▶ Remote control of the system from multiple devices.
▶ Diagnostics, also by email.
▶ Reset.
▶ Gas unit heater data display and parameters setting.
▶ Space heating and summer ventilation setpoint set-
ting.
▶ Summer ventilation mode activation.
For further details and diagrams see the Genius software
instruction sheet for remote control of the OSWR000
generators.
1.4.7 External request
The appliance may also be controlled via generic enable
devices (e.g. thermostat, timer, switch, contactor...) tted
with voltage-free NO contact.
For managing the request signal (Z9 contact), Robur pro-
vides as optional dierent models of thermostats and
chronothermostats.
For a list of thermostats and chronothermostats available
as optional, see Paragraph 1.4.8 p.13 .
For further details and diagrams see Paragraph
4.4.2 p.24 .
1.4.8 Other optional thermostats and
chronothermostats
For managing the request signal (Z9 contact), Robur pro-
vides as optional dierent models of thermostats and
chronothermostats, listed below.
▶ Room thermostat with ON/OFF switch (optional
O12301035)
▶ Sealed room thermostat IP55 (optional O12301025)
▶ Digital programmable chronothermostat (optional
OCDS005)

Features and technical data
14
1
1.5 ELECTRICAL PANEL
Figure1.10Electrical panel
A Internal components protection thermostat
B Limit thermostat
C Dierential pressure switch
D Controller for ignition, adjustment and ame control
E Pressure switch control relay
B
E
C
D
A
1.6 TECHNICAL DATA
Table1.2Technical data
Axial fan models
M20 M25 M30 M35 M36 M40 M50 M60
Heating mode
Heat input nominal (1013 mbar - 15 °C)
(1) kW 20,6 28,8 34,8 42,2 39,4 48,2 57,3 72,5
Heat output nominal kW 18,3 25,5 30,7 37,4 34,9 42,5 50,7 63,8
Eciency nominal heat input % 88,8 88,5 88,2 88,6 88,5 88,2 88,5 88,0
useful at 100% heat input % 88,5 88,2 87,9 88,3 88,2 87,8 88,0 87,5
Heat losses
to ue in operation % 11,20 11,50 11,80 11,40 11,50 11,80 11,50 12,00
to casing in operation % 0,30 0,40 0,50
with burner o % 0,25
Temperature rise nominal heat input K 20,5 29,4 23,8 28,6 26,6 27,8 29,8 27,3
lenght of throw (residual speed < 0,5 m/s) (2) m 12,0 15,0 18,0 20,0 21,0 23,0 25,0
Ambient air temperature (dry bulb) maximum °C 35
minimum °C 0
Electrical specications
Power supply
voltage V 230
type - single-phase
frequency Hz 50
Electrical power absorption nominal kW 0,25 0,24 0,34 0,40 0,50 0,61
fuse A 4,0
Degree of protection fan motor IP 42 44 54 44 54
appliance IP 20
(1) Relative to NCV (net caloric value).
(2) Values measured in an open area; in a real installation, the thermal ow may reach greater distances than those given here (depending on the height of the ceiling
and its thermal insulation).

Transport and positioning
Installation, use and maintenance manual – M gas unit heater 15
2
M20 M25 M30 M35 M36 M40 M50 M60
Installation data
Gas consumption
G20 natural gas (nominal) m³/h 2,18 3,05 3,68 4,47 4,17 5,10 6,06 7,67
G25 (nominal) m³/h 2,54 3,54 4,28 5,19 4,85 5,93 7,05 8,92
G25.1 (nominal) m³/h 2,53 3,54 4,28 5,19 4,84 5,92 7,04 8,91
G25.3 (nominal) m³/h 2,48 3,47 4,19 5,08 4,74 5,80 6,89 8,72
G27 (nominal) m³/h 2,66 3,72 4,49 5,45 5,09 6,22 7,40 9,36
G2.350 (nominal) m³/h 3,03 4,23 5,12 6,20 5,79 7,09 8,42 10,66
G30 (nominal) kg/h 1,63 2,27 2,74 3,33 3,11 3,80 4,52 5,72
G31 (nominal) kg/h 1,60 2,24 2,70 3,28 3,06 3,75 4,45 5,63
Air ow nominal m³/h 2630 2550 3800 3850 4500 5000 6875
Gas connection type - M
thread “ 1/2 3/4
Flue gas exhaust
diameter (Ø) mm 110
residual head Pa 40 30 35 42 30 27 69
type of installation - B22, C12, C32, C62
Combustion air intake connection diameter (Ø) mm 130
recommended height m 2,5 2,5 ÷
3,0 3,0 ÷ 3,5
sound power Lw(max) dB(A) 67,5 70,5 72,5 72,0 74,5 71,5 76,5
sound pressure Lpat 5 metres (max) dB(A) 45,5 48,5 50,5 50,0 52,5 49,5 54,5
Dimensions
width mm 630 770 880 1070 1270
depth mm 631 590 624 643 590 624
height mm 800
Weight in operation kg 55 59 68 80 90 108
(1) Relative to NCV (net caloric value).
(2) Values measured in an open area; in a real installation, the thermal ow may reach greater distances than those given here (depending on the height of the ceiling
and its thermal insulation).
Centrifugal fan models
M20 C M30 C M60 C
Heating mode
Temperature rise nominal heat input K 19,2 22,6 23,5
Electrical specications
Electrical power absorption nominal kW 0,41 0,75 1,30
fuse A 6,3
Installation data
Air ow at maximum available head m³/h 1900 3100 6400
free blowing m³/h 2800 4000 8000
maximum useful pressure head Pa 110
minimum pressure drop on heat ow delivery Pa 0 50 30
sound power Lw(max) dB(A) 74,0 78,0 81,0
sound pressure Lpat 5 metres (max) dB(A) 52,0 56,0 59,0
Dimensions
width mm 632 772 1272
depth mm 948 992
height mm 800
Weight in operation kg 66 82 133
The M36 model is only available for the French market.
2 TRANSPORT AND POSITIONING
2.1 WARNINGS
Damage from transport or installation
The manufacturer shall not be liable for any dam-
age during appliance transport and installation.
On-site inspection
Upon arrival at the site, ensure there is no transport
damage on packing or metal panels.
After removing the packing materials, ensure the
appliance is intact and complete.

Transport and positioning
16
2
Packing
Only remove the packing after placing the appli-
ance on site.
Do not leave parts of the packing within the reach
of children (plastic, polystyrene, nails...) since they
are potentially dangerous.
Weight
The lifting equipment must be suitable for the load.
Lift up the unit and secure it to its support bracket
(Paragraph 2.5 p.17 ).
2.2 HANDLING
2.2.1 Handling and lifting
▶ Always handle the appliance in its packing, as deliv-
ered by the factory.
▶ Comply with safety regulations at the installation site.
2.3 APPLIANCE POSITIONING
The unit must be installed in the room to be heated.
2.3.1 Where to install the appliance
The wall or structure on which the unit is to be
installed must be load-bearing or, in any case, suit-
able for supporting its weight.
Installation must not be made on walls with poor
strength that do not guarantee adequate resist-
ance to the stresses produced by the unit. The
manufacturer does not assume any responsibility
if the appliance is installed on surfaces or walls that
are not suitable for supporting its weight.
The appliance's ue gas exhaust must not be im-
mediately close to openings or air intakes of build-
ings, and must comply with safety and environ-
mental regulations.
To obtain the maximum system eciency it is advisable to
comply with the following rules:
▶ Make sure that the air ow does not directly impinge
on the sta (by tilting the grille louvres appropriately).
▶ Take any obstacles into account (pillars or other).
▶ Consider length of throw of the unit (Table 1.2 p.14 ).
▶ For better heat distribution in the case of multiple unit
installations, create alternate ows of warm air (see
Figure 2.1 p.16 ).
▶ In some cases it may also be suitable to place the units
close to the main doors, so that they can also operate
as air barriers when doors are opened.
Figure2.1Airow distribution
2.4 MINIMUM CLEARANCE DISTANCES
2.4.1 Distances from combustible or ammable
materials
▶ Keep the appliance away from combustible or am-
mable materials or components, in compliance with
applicable regulations.
2.4.2 Clearances around the appliance
Axial gas unit heaters
The minimum clearance distances are required for
safety, operation and maintenance.

Transport and positioning
Installation, use and maintenance manual – M gas unit heater 17
2
Figure2.2Clearances
A Gas unit heater width B Object or structure underneath the gas unit heater
B
> 350 mm
> 400 mm
< 3,5 m
> 2,5 m
> 200 mm A A
> 500 mm
The recommended height from the oor to the
gas unit heater base is 2,5 to 3,5 m (see Figure
2.2 p. 17 ). We do not recommend installing the
gas unit heaters at heights below 2,5 m from the
oor.
The minimum distance from the wall must be at
least 35 cm.
2.4.2.1 Centrifugal gas unit heaters
The position of gas unit heaters with centrifugal fan must
consider the position of the warm air duct. This must be
suitably sized and veried in relation to the air ow rate
and the head of the centrifugal fan (Paragraph 3.4 p.22 ).
The recommended height from the oor to the
gas unit heater base is 2,5 to 3,5 m (see Figure
2.2 p. 17 ). We do not recommend installing the
gas unit heaters at heights below 2,5 m from the
oor.
2.5 SUPPORT BRACKET
Robur provides easy mounting support brackets as an
optional, suitably designed for M series gas unit heaters,
which allow simplifying the wall xing.
If you do not want to use these options, refer to Figure
2.3 p.17 .
When xing the unit to the support brackets, use 4 M10
bolts.
Figure2.3Installation with support bracket
A Gas unit heater xing points centre distance
B Support bracket length
40405
B
A
Table2.1Support bracket dimensions for axial gas unit heaters
M20 M25 M30 M35/M36 M40 M50 M60
A370 370 510 620 620 810 1010
B840
Table2.2Support bracket dimensions for centrifugal gas unit
heaters
M20 C M30 C M60 C
A370 510 1010
B1400

Heating engineer
18
3
2.5.1 Axial gas unit heaters
For axial gas unit heaters the following support brackets
are available as optional:
▶ O19800020 revolving wall support bracket (M20, M25
models)
▶ O19800024 revolving wall support bracket (M30 mod-
el)
▶ OKMN000 swivel bracket (models M35, M36, M40)
▶ O19800026 revolving wall support bracket (M50 mod-
el)
▶ O19800028 revolving wall support bracket (M60 mod-
el)
▶ OSTF009 support bracket 1,4 m length
▶ Tubular bracket OSTF005
All support brackets are supplied with bolts and the rear
support plate.
For mounting instructions of the brackets, refer to the rel-
evant instruction sheets.
2.5.2 Centrifugal gas unit heaters
For centrifugal gas unit heaters, the following mounting
brackets are available as optional:
▶ OSTF009 support bracket 1,4 m length
All support brackets are supplied with bolts and the rear
support plate.
For mounting instructions of the brackets, refer to the rel-
evant instruction sheets.
3 HEATING ENGINEER
3.1 WARNINGS
3.1.1 General warnings
Read the warnings in Chapter III.1 p. 4 , pro-
viding important information on regulations and
on safety.
Compliance with installation standards
Installation must comply with applicable regula-
tions in force, based on the installation Country
and site, in matters of safety, design, implementa-
tion and maintenance of:
heating systems
gas systems
ue gas exhaust
ue gas condensate discharge
Installation must also comply with the manufactur-
er's provisions.
3.2 FUEL GAS SUPPLY
3.2.1 Gas connection
▶ 1/2" M (models M20, M25, M30, M35, M36, M40)
▶ 3/4" M (M50, M60 models)
on the rear, to the left (see dimensional diagrams,
Paragraph 1.2 p.8 ).
▶ Install an anti-vibration connection between the ap-
pliance and the gas piping.
3.2.2 Mandatory shut-o valve
▶ Provide a gas shut-o valve (manual) on the gas supply
line, next to the appliance, to isolate it when required.
▶ Provide a three-piece pipe union.
▶ Perform connection in compliance with applicable
regulations.
3.2.3 Gas pipes sizing
The gas pipes must not cause excessive pressure drops
and, consequently, insucient gas pressure for the
appliance.
3.2.4 Supply gas pressure
This appliance is equipped for a maximum gas
supply pressure of 50 mbar.
The appliance's gas supply pressure, both static and dy-
namic, must comply with Table 3.1 p.18 , with tolerance
± 15%.
Non compliant gas pressure (Table 3.1 p. 18 )
may damage the appliance and be hazardous.
Table3.1Network gas pressure
Gas supply pressure [mbar]
Product
category Countries of destination G20 G25 G25.1 G25.3 G2.350 G27 G30 G31
II2H3B/P
AL, BG, CH, CY, CZ, DK, EE, FI, GR, HR, IT, LT, LV, MK, NO,
RO, SE, SI, SK, TR 20 30 30
AT, CH 20 50 50
II2H3P
AL, BG, CH, CZ, ES, GB, GR, HR, IE, IT, LT, LV, MK, PT, SI,
SK, TR 20 37
RO 20 30
AT 20 50
II2ELL3B/P DE 20 20 50 50

Heating engineer
Installation, use and maintenance manual – M gas unit heater 19
3
II2Esi3P FR 20 25 37
II2Er3P 20 25 37
II2H3B/P HU 25 30 30
II2HS3B/P 25 25 30 30
II2E3P LU 20 50
II2L3B/P
NL
25 30 30
II2L3P 25 37
II2EK3B/P 20 25 30 30
II2EK3P 20 25 30
II2E3B/P
PL
20 37 37
I2E 20
II2ELwLs3B/P 20 13 20 37 37
II2ELwLs3P 20 13 20 37
I2E(R)
BE
20 25
I2E(S) 20 25
I3P 37
I3P IS 30
I2H LV 20
I3B/P MT 30 30
I3B 30
The appliance gas supply pressure, both static and dynamic, must comply with the values in theTable, with a tolerance of ± 15%.
3.2.5 Vertical pipes and condensate
▶ Vertical gas pipes must be tted with siphon and dis-
charge of the condensate that may form inside the
pipe.
▶ If necessary, insulate the piping.
3.2.6 LPG pressure reducers
With LPG the following must be installed:
▶ A rst stage pressure reducer, close to the liquid gas
tank.
▶ A second stage pressure reducer, close to the appli-
ance.
3.3 COMBUSTION PRODUCTS EXHAUST
Compliance with standards
The appliance is approved for connection to a
combustion products exhaust duct for the types
shown in Table 1.2 p.14 .
3.3.1 Flue gas exhaust connection
▶ Ø 110 mm, on the rear side, at the top (see dimension-
al drawings in the 1.2 p.8 Section).
3.3.2 Combustion air intake tting
▶ Ø 130 mm, on the rear side, at the top (see dimension-
al drawings in the 1.2 p.8 Section).
3.3.3 Installation types
If ducts other than those supplied by the manufac-
turer are used, make sure that they are suitable for
the unit on which they are installed. In particular,
the temperature class of the duct must be ap-
propriate for the operating characteristics of the
unit, and must also respect the chemical-physical
stability of the system itself.
In any case, use approved ducts according to the
type of installation to be made. Upon request,
Robur can supply rigid pipes, coaxial ducts and ter-
minals, all of approved type.
Gas unit heaters of the M series can be installed to one of
the following ways.
3.3.3.1 B22 type installation with wall ue gas exhaust
pipe
Figure3.1B22 type installation with wall ue gas exhaust pipe
A View from above
A

Heating engineer
20
3
3.3.3.2 B22 type installation with roof ue gas exhaust
pipe
Figure3.2B22 type installation with roof ue gas exhaust pipe
3.3.3.3 C12 type installation with separate ducts
Figure3.3C12 type installation with separate ducts
A View from above
1 Flue gas exhaust
2 Combustion air inlet
A
1 2
3.3.3.4 C12 type installation with wall coaxial terminal
Figure3.4C12 type installation with wall coaxial terminal
A View from above
A
3.3.3.5 C32 type installation with roof coaxial terminal
Figure3.5C32 type installation with roof coaxial terminal
3.3.3.6 C62 type installation with separate ducts
Figure3.6C62 type installation with separate ducts
3.3.4 Sizing and installing combustion air/
exhaust fumes ducts
In order to dimension the duct system, the total pressure
drop of the system must be calculated.
The total permissible pressure drop in the pipe system de-
pends on the model of the instrument and any diaphragm
tted (Table 3.2 p.21 ).
The pressure drops of the ue and air pipes available as
Robur optional are shown in Table 3.3 p.21 .
The pressure drops of the coaxial pipes available as Robur
optional are shown in Table 3.3 p.21 .
Resistance from the separate terminals are negligible
since they are very low.
In the design phase it is necessary to verify that the sum of
the pressure drops of the pipe system used is lower than
the maximum pressure drop allowed by the device (Table
3.2 p. 21 ). The 3.3.5 p. 22 Section provides an exam-
ple of how to calculate the pressure drop.