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