HDG F20 User manual

hdg-bavaria.com
HDG F20/25/30
HDG F40/50
Operating manual

Operating manual HDG F20-50 - Content
3
Content
1 Notes on this manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.2 Glossary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2 Safety notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1 Intended use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Basic system design principles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Basic principles for the content of the operating manual . . . . . . . . . . . . . . . . . . . . 8
Proper and improper operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2 Residual risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.3 Warnings and safety symbols used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
2.4 Duty of information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
3 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
3.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Front view HDG F20-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Cross section of HDG F20-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Rear and side views HDG F20-50. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
3.2 Functional description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Boiler HDG F20-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Boiler and weather-compensated heating control HDG controls. . . . . . . . . . . .17
3.3 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
HDG F20/25/30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
HDG F40/50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
3.4 Fuel quality requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Log wood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Pressed wood briquettes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Recommended fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Permitted fuel in accordance with 1st Federal Emission Control
Ordinance (Germany) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
4 Planning and installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
4.1 Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
4.2 Structural requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Boiler installation site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Required room sizes and minimum clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
4.3 Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Chimney . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Electrical system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
4.4 Hydraulic connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
4.5 Scope of delivery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
4.6 Installing the heating system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

Operating manual HDG F20-50 - Content
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Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Installing the boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Installing hydraulic connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Installing the HDG controls control unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Installing the automatic ignition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Installing the automatic cleaning system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Fitting the cladding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.7 Connecting the chimney. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
4.8 Electrical system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
4.9 Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
4.10 Connecting the thermal safety device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
5 Commissioning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
5.1 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
5.2 Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Switching on the heating system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Testing system components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
6 Using the heating system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
6.1 Control unit for HDG controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
6.2 Switching on the heating system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Emergency heating switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Fuel selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
6.3 Heating up the system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
General information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
6.4 Performing a chimney sweep measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Before the test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
On the day of the test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
During the test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
6.5 Switching off the heating system for repair work . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
6.6 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
7 Cleaning and servicing the heating system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
7.1 Cleaning and servicing schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
7.2 Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Generally applicable safety instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Cleaning tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Cleaning the fuel chamber and secondary air openings . . . . . . . . . . . . . . . . . . . 67
Cleaning the secondary combustion chamber and the ash compartment . . 69
Checking and cleaning the lambda sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Cleaning the flue gas temperature sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Cleaning the flue gas pipe. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Cleaning the cleaning system, heat exchanger surfaces and flue gas flap. . . 72
Cleaning the flue gas fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Cleaning the air control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Cleaning the panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Operating manual HDG F20-50 - Content
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Checking the doors are tight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78
Cleaning the ignition fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80
8 Notes on dismantling and disposal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82
8.1 Dismantling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82
8.2 Disposal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83
9 Declaration of Conformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .84
10 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85

1 Notes on this manual – Introduction
6
1 Notes on this manual
1.1 Introduction
SAFE AND SIMPLE OPERATION This Operating manual contains important instructions on the boiler
•HDG F20/25/30
•HDG F40/50
and how to operate it properly and safely. Following these
instructions helps to avoid dangers, prevent repair costs and
downtimes, maintain reliability and extend the life expectancy of the
heating system.
READING THE OPERATING
MANUAL
This Operating manual must be read and observed by everyone who
operates or works on the HDG F20-50.
TECHNICAL CHANGES We continuously develop and improve our boilers. The information
in this edition was correct at the time of going to press.
We reserve the right to make changes which may then differ from the
technical details and illustrations in this Operating manual.
COPYRIGHT Written permission is required from HDG Bavaria GmbH for
reprinting, storage in a data-processing system or transmission by
electronic, mechanical, photographic or any other means, and for
copies or translations of this publication, in whole or in part.
GUARANTEE The terms and conditions of the guarantee of your boiler can be
found in the enclosed information sheet.
SYMBOLS USED In this Operating manual, the following designations and symbols
are used for particularly important information:
1. Instructions to the operator
2. Work through the steps in the sequence specified.
✓Result of the action described
✎Cross reference for more explanation
•List
–List

1 Notes on this manual – Glossary
7
1.2 Glossary
Term Explanation
Actuator This is a component which carries out a certain function in the
heating system, e.g. flue gas fan.
Central module Pre-fabricated plug board for electrical components.
Display Display on the control unit HDG controls.
Flue gas fan Creates a vacuum inside the boiler and provides the boiler with air
for combustion.
HDG controls Boiler and heating system controller.
HDG F20-50 Boiler for burning untreated wood.
HDG F20-50 Hybrid Boiler for burning untreated wood. The HDG F Hybrid is also
intended for combined used with a HDG K Hybrid pellt unit
Lambda sensor This is an electrical component which monitors residual oxygen
levels in the flue gas.
Safety temperature limiter An automatic device that interrupts and locks the supply of energy
and combustion air when the maximum permissible boiler
temperature is reached. The energy supply or combustion air
supply can only be re-enabled after the boiler temperature has
fallen below a preset limit and has been reset by hand or by means
of a tool.
Sensor Monitors certain parameters (e.g. temperature) and forwards them
to the control system for analysis.
Thermal safety device Safety device that allows cold water to flow through the safety
heat exchanger if the boiler becomes too hot.
Table 1/1 - Glossary

2 Safety notes – Intended use
8
2 Safety notes
2.1 Intended use
BASIC SYSTEM DESIGN PRINCIPLES
BASIC PRINCIPLES The heating system was built using state-of-the-art technology and
conforms to recognised safety regulations. Nevertheless, there is still
a risk of injury or death to users or bystanders, and of adverse effects
upon the heating system or upon other material goods. Have your
specialist heating company provide you with detailed instruc-
tions on the operation of the heating system.
USING THE HEATING SYSTEM Only use the heating system when it is in perfect condition. Use it
properly, as intended, be aware of safety and hazards, and observe
the Operating manual. Have any faults which could impair safety
fixed immediately.
This device can be used by children over 8 years old and people with
reduced physical, sensory or mental capabilities or a lack of experi-
ence and knowledge, provided they are supervised or have been in-
structed on the safe use of the device and understand the resulting
risks. Children may not play with the device. Cleaning and user main-
tenance must not be carried out by children without supervision.
BASIC PRINCIPLES FOR THE CONTENT OF THE OPERATING MANUAL
SCOPE The content of this operating manual is intended exclusively for the
planning, installation and operation of the HDG F20-50 boiler. The
further implementation of applicable standards and guidelines, for
example regarding installation of the heating system (pipework,
etc.), is not part of this operating manual. HDG Bavaria does not as-
sume any liability for this.
PROPER AND IMPROPER OPERATION
PURPOSE OF THE HEATING
SYSTEM
The HDG F20-50 boiler is designed for the standard operation of
burning untreated wood, for example in the form of split logs and
pressed wood briquettes in hot-water heating systems.
Any other application is considered improper use. The manufacturer
will accept no liability for any damage resulting from improper use.
The operator bears sole responsibility in such cases.
Proper use includes adherence to the installation, operation and
maintenance requirements specified by the manufacturer.

2 Safety notes – Residual risks
9
Modification of the specified operating values will affect the heating
system’s control programme and could lead to malfunctions. Only
trained maintenance and operating personnel may undertake modi-
fications to the operating values.
2.2 Residual risks
Despite all precautions, the following residual risks remain:
For more information on fuel, see chapter “3 Mode of operation”,
section “3.4 Fuel quality requirements”.
Caution!
Hot surfaces
Contact with the hot surfaces of the boiler (e.g. inside doors, flue
pipe, etc.) can result in burns. Even after the boiler is switched off,
the surfaces only cool down slowly.
Wait until the boiler has cooled down before touching non-insu-
lated components.
Danger!
Danger of asphyxiation due to carbon monoxide
If the boiler is in operation, carbon monoxide can be emitted
through the open doors or lids.
Always keep the doors and lids closed. Only open them when the
boiler has finished burning. Do not leave them open any longer
than necessary and never leave them open unattended.
Warning!
Danger of fire
When the heating system is in operation, open doors and lids con-
stitute a fire hazard. Furthermore, combustion residue (ash, char-
coal etc.) can reignite after being removed from the boiler.
Always keep the doors and lids closed. Only open them when the
boiler has finished burning. Do not leave them open any longer
than necessary and never leave them open unattended. Put the an-
nealed combustion residue in the ash pan of a non-flammable and
closable container.

2 Safety notes – Warnings and safety symbols used
10
2.3 Warnings and safety symbols used
The following warnings and safety symbols are used in this Oper-
ating manual:
Danger!
Danger of explosion
A concentration of carbon monoxide that is too high can result in
an explosion.
Observe the flue draught requirement of the chimney.
Caution!
Risk of injury from automatically driven components
Working on the flue gas fan can lead to hand injuries due to the
moving parts.
When working on the flue gas fan, disconnect it from the mains.
Danger!
Electric shock
Working on live components (such as the plug board) can result in
an electric shock.
Work on the live components may only be carried out by a qualified
electrician. Make sure the system is disconnected from the mains
and prevented from being switched on again.
Warning!
The boiler is under pressure.
Danger!
Dangerous electrical current or voltage
Work in areas marked with this symbol may only be performed by a
qualified electrician.
Warning!
Hazardous area
Working in areas marked with this symbol can lead to serious inju-
ries or to extensive material damage.
Caution!
Hot surfaces
Working in areas marked with this symbol can lead to burns.

2 Safety notes – Warnings and safety symbols used
11
Warning!
Danger of fire
Working in areas marked with this symbol can lead to a fire.
Danger!
Danger of asphyxiation due to lack of oxygen
When working in areas marked with this symbol, there is a danger
of asphyxiation due to high concentrations of carbon monoxide.
Warning!
Automatic start-up
Working in areas marked with this symbol can lead to injuries due
to automatic start-up.
Danger!
Danger of explosion
A concentration of carbon monoxide that is too high can result in
an explosion.
Caution!
Danger from suspended loads
Working in areas with this symbol may involve danger from falling
objects.
Important!
Frost danger
Only install the heating system in a frost-proof room.
Instructions regarding disposal
Additional information for the operator

2 Safety notes – Duty of information
12
2.4 Duty of information
READING THE OPERATING
MANUAL
Any person performing tasks on this system must read the Operating
manual prior to beginning work, particularly the chapter “2 Safety
notes”.
This is especially important for persons who only occasionally work
on the heating system, for example when cleaning or servicing it.
The Operating manual must always be kept readily accessible at the
place where heating system is installed.

3 Mode of operation – Overview
13
3 Mode of operation
3.1 Overview
FRONT VIEW HDG F20-50
1 Control unitHDG Control Touch
2 Flue gas flap actuating handle
3Fuelchamber
4Ashpan
5 Combustion chamber door
6 Actuator secondary air
7 Actuator primary air
8 Fuel chamber door
9 Cleaning system actuating handle
10 Overheat cut-off device release button
Figure 3/1 - Front view HDG F20-50
5
28
9
1
4
7
6
3
10

3 Mode of operation – Overview
14
CROSS SECTION OF HDG F20-50
1Centralmodule
2 EM4 extension module (optional)
3Sidepanels
4 Burner nozzle
5Ashcompartment
6 Combustion chamber
7 Nozzle brick
8Backpanels
9 Tubular heat exchanger
10 Cleaning turbulators
11 Flue gas flap
12 Cleaning shaft lid
Figure 3/2 - Cross section of HDG F20-50
6
7
11
9
8
12
5
4
2
1
3
10

3 Mode of operation – Overview
15
REAR AND SIDE VIEWS HDG F20-50
1 Safety heat exchanger inlet (DN 15 male)
2 Immersion sleeve for boiler temperature and STL sensor
3 Safety heat exchanger outlet (DN 15 male)
4 Connection of immersion sleeve for thermal
safety device (DN 15 IG)
5 Supply connection (DN 32 inside thread)
6 Cleaning motor (optional)
7 Ignition fan (optional)
8 Filling/draining connection (DN 15 IG)
9 Flue pipe connection 150 mm
10 Flue gas temperature sensor
11 Lambda sensor
12 Flue gas fan
13 Immersion sleeve for return temperature sensor
14 Return connection (DN 32 inside thread)
Figure 3/3 - Rear and side views HDG F20-50
4
8
9
3
1
14
7
5
2
11
13
6
10
12

3 Mode of operation – Functional description
16
3.2 Functional description
BOILER HDG F20-50
GENERAL INFORMATION The HDG F20-50 is a special boiler for the firing of wood up to 50 cm
in length. The HDG controls system regulates the combustion and
output as well as the weather-compensated heating. The HDG F20-
50 boiler and the HDG controls system are harmonised with one
another and form a functional unit. This enables wood to be
converted into heat energy in an environmentally sound and
convenient manner.
COMBUSTION PROCESS
Inside the HDG F20-50 boiler, fuel which has been manually placed in
the fuel chamber (4) and ignited is degassed through the addition of
primary air. It can also be ignited automatically using the ignition fan
(7). The resulting wood gas is mixed with secondary air in the
combustion chamber (2) where it is burnt off.
Ashes are collected in the large ash compartments (6) for
combustion ash and fly ash.
The air necessary for combustion is supplied as required via the
suction fan (8) and two actuators (5) with metering mechanisms.
The lambda sensor, the boiler temperature sensor and the flue gas
temperature sensor are used to do the following:
•To continuously monitor the firing
•To adjust the boiler output
Figure 3/4 - Boiler HDG F20-50
4
1
68
2
3
5
7

3 Mode of operation – Functional description
17
•To minimise emissions
•To optimise boiler efficiency
CLEANING SYSTEM When the actuating handle (3) of the cleaning system is pulled, the
heat exchanger surfaces are cleaned by the turbulators (1) located
inside. The turbulators can also be moved automatically using the
drive motor.
BOILER AND WEATHER-COMPENSATED HEATING CONTROL HDG
CONTROLS
BOILER CONTROL UNIT The HDG controls boiler control unit is the electronic hub of the
boiler. It consists of the ready-to-use control panel and control unit
HDG Control Touch on the front of the boiler. Using the control unit,
you can regulate the boiler and call up information on the current
process.
HEATING CIRCUIT CONTROL The HDG controls controls the entire energy management of the
heating system including the following, depending on the version:
•Accumulator management
•Weather-compensated heating circuits
•Domestic hot water heating
•External heat source
•Local heating transfer (mains pump)
•Solar system for hot water and support of the heating system
✎For a description of the HDG controls boiler and weather-
compensated heating control, refer to the “HDG controls”
operating manual.

3 Mode of operation – Technical data
18
3.3 Technical data
HDG F20/25/30
Type of boiler HDG F20 HDG F25 HDG F30
Performance data (measured according to DIN EN 303-5)
Nominal thermal power 20 kW 25 kW 30 kW
Minimum thermal power 15 kW 15 kW 15 kW
Boiler efficiency at nominal thermal power 93.8 % 93.4 % 93.0 %
Electrical power consumption at nominal
thermal power
78 W 82 W 85 W
Voltage / frequency AC 1 x 230 V / 50 Hz
Back-up fuse 10 A
General boiler data
Boiler class 5
Maximum permissible operating pressure 3 bar
Maximum supply temperature 95 °C*
Minimum return temperature 60 °C
Water capacity 125 l
Fuel chamber capacity 155 l
Weight 670 kg
Layout data for flue calculation (DIN EN 13384-1)
Flue gas temperature (Tw) at
Nominal thermal power / lowest thermal
power
120 °C / 120 °C 130 °C / 120 °C 140 °C / 120 °C
Flue gas mass flow at
Nominal thermal power / lowest thermal
power
0.013 /0.010 kg/s 0.013 / 0.010 kg/s 0.013 / 0.010 kg/s
CO2content at
Nominal thermal power / lowest thermal
power
14.2 % / 13.3 % 14.2 % / 13.3 % 14.2 % / 13.3 %
Required flue draught (Pw) 10 Pa 10 Pa 10 Pa
Diameter of flue pipe connection 150 mm
Height to centre of flue gas connecting pipe 1040 mm
Water-side connections
Supply and return connections (bushing) DN 32, inside thread
Safety heat exchanger connections
(bushing)
DN 15, outside thread
Connection for filling/draining (bushing) DN 15, inside thread
Recommended pipe dimensions (minimum) DN 32
Water-side resistance at nominal thermal
power
10 K / 20 K 1600 Pa / 400 Pa 2000 Pa / 500 Pa 2400 Pa / 600 Pa
Table 3/1 - HDG F20/25/30 technical data

3 Mode of operation – Technical data
19
*Maximum operating temperatures of up to 110 °C can also briefly
occur.
HDG F40/50
Other information
Combustion duration per filling in terms of
fuel recommendation, approx.
Beech: up to 7 h
Spruce: up to 6 h
Beech: up to 6 h
Spruce: up to 5 h
Beech: up to 5 h
Spruce: up to 4 h
Sound pressure level < 70 dB(A)
Min. Air inlet cross section 150 cm2
Type of boiler HDG F20 HDG F25 HDG F30
Table 3/1 - HDG F20/25/30 technical data
Type of boiler HDG F40 HDG F50
Performance data (measured according to DIN EN 303-5)
Nominal thermal power 40 kW 50 kW
Minimum thermal power 25 kW 25 kW
Boiler efficiency at nominal thermal power 93.7 % 94.3 %
Electrical power consumption at nominal
thermal power
74 W 63 W
Voltage / frequency AC 1 x 230 V / 50 Hz
Back-up fuse 10 A
General boiler data
Boiler class 5
Maximum permissible operating pressure 3 bar
Maximum supply temperature 95 °C*
Minimum return temperature 60 °C
Water capacity 180 l
Fuel chamber capacity 205 l
Weight 830 kg
Layout data for flue calculation (DIN EN 13384-1)
Flue gas temperature (Tw) at
Nominal thermal power / lowest thermal
power
130 °C / 120 °C 140 °C / 120 °C
Flue gas mass flow at
Nominal thermal power / lowest thermal
power
0.022 kg/s / 0.014 kg/s 0.031 kg/s / 0.014 kg/s
CO2content at
Nominal thermal power / lowest thermal
power
14.4 % / 14.5 % 14.6 % / 14.5 %
Required flue draught (Pw) 10 Pa 10 Pa
Diameter of flue pipe connection 150 mm
Height to centre of flue gas connecting pipe 1070 mm
Water-side connections
Supply and return connections (bushing) DN 32, inside thread
Safety heat exchanger connections
(bushing)
DN 15, outside thread
Table 3/2 - HDG F40/50 technical data

3 Mode of operation – Fuel quality requirements
20
*Maximum operating temperatures of up to 110 °C can also briefly
occur.
3.4 Fuel quality requirements
The HDG F20-50 boiler is designed for the standard use of burning
untreated wood in the form of logs or pressed wood briquettes.
LOG WOOD
Essential criteria are the length, diameter and water content of the
fuel.
LENGTH AND DIAMETER For the log wood boiler HDG F20-50, firewood with a length of up to
50 cm (L50) can be used. The maximum diameter of the firewood is
specified as D15 (diameter of maximum 15 cm).
The firewood must be split at least once so as to provide an optimal
surface for gasifying the wood. The major proportion of the firewood
should measure between 8 and 12 cm in diameter.
WATER CONTENT When selecting fuel, note that the calorific value of the wood is
primarily dependent on the water content. The more water
contained in the wood, the smaller the calorific value, since the water
vaporises in the course of the burning process and thereby
consumes heat. This leads to a decreased efficiency and thus to
higher fuel consumption. A higher water content in the fuel also
results in a steadily decreasing output of the (central-heating) boiler,
Connection for filling/draining (bushing) DN 15, inside thread
Recommended pipe dimensions (minimum) DN 32
Water-side resistance at nominal thermal
power
10 K / 20 K 1500 Pa / 300 Pa 1700 Pa / 400 Pa
Other information
Combustion duration per filling in terms of
fuel recommendation, approx.
Beech: up to 6 h
Spruce: up to 5 h
Beech: up to 5 h
Spruce: up to 4 h
Sound pressure level < 70 dB(A)
Min. Air inlet cross section 150 cm2
Type of boiler HDG F40 HDG F50
Table 3/2 - HDG F40/50 technical data
With regard to the quality standards for solid fuel the DIN EN ISO
17225 “Biogenic solid fuel - fuel specifications and classes -
classification of wood chips” applies.
•Part 5 “Classification of log wood”
•Part 3 “Classification of wood briquettes”
In accordance with this standard, the properties of fuels that can be
used with the HDG F20-50 are specified below in more detail.