Motortech VARIFUEL2 User manual

VariFuel2/2+ – Air/Gas Mixer
Assembly Instructions
P/N 01.10.001-EN | Rev. 09/2020

Original assembly instructions
© Copyright 2020 MOTORTECH GmbH. All rights reserved.
MOTORTECH products and the MOTORTECH logo are registered and/or common law trademarks
of the MOTORTECH GmbH. All further trademarks and logos displayed or used in this publication
are the property of the respective entitled person and are used for reference purposes only.
Information contained in this publication may be changed without prior notice.

Rev. 09/2020 3
1 General Information .....................................................................................................5
1.1 What Is the Purpose of these Assembly Instructions?.................................................5
1.2 Who Are these Assembly Instructions Targeted to?....................................................5
1.3 What Symbols Are Used in the Assembly Instructions? ..............................................5
1.4 Which Abbreviations/Acronyms Are Used in the Assembly Instructions?.....................6
2 Safety Instructions ......................................................................................................7
2.1 General Safety Instructions ..................................................................................... 7
2.2 Electrostatic Discharge Hazards ..............................................................................8
2.3 Special Safety Instructions for the Device ................................................................8
2.4 Proper Transport .................................................................................................. 10
2.5 Proper Storage ..................................................................................................... 10
2.6 Proper Disposal.................................................................................................... 10
3 Intended Use ............................................................................................................. 11
3.1 Functional Description ...........................................................................................11
3.2 Applications......................................................................................................... 13
4 Product Description ................................................................................................... 15
4.1 Technical Data ...................................................................................................... 15
4.1.1 Certifications ..................................................................................................... 15
4.1.2 Mechanical Data ................................................................................................ 16
4.1.3 Warning Notices on the Device............................................................................ 17
4.1.4 Product Identification – Labeling on the Device.................................................... 18
4.1.5 Overview Drawings............................................................................................. 19
4.1.6 Pole Connector Stepper Motor / Encoder .............................................................26
4.1.7 Digression: Direct Control of Stepper Motor ......................................................... 27
5 Installation Instructions............................................................................................ 28
5.1 Unpacking............................................................................................................28
5.2 Assembly .............................................................................................................29
5.2.1 Install Flow Body................................................................................................ 31
5.2.2 Install VariFuel2/2+ into Intake Section .............................................................. 33
5.2.3 Connect Stepper Motor Driver............................................................................. 35
6 Operation ..................................................................................................................36
6.1 Start-up ...............................................................................................................36
7 Errors........................................................................................................................ 38
7.1 Special Tools for Troubleshooting ..........................................................................38
7.2 Possible Faults .....................................................................................................38
Table of Contents

Table of Contents
4 Rev. 09/2020
7.3 Fix Shaft .............................................................................................................. 41
7.4 Adjust Fuel Ring....................................................................................................44
7.5 Customer Service Information ...............................................................................46
7.6 Returning Equipment for Repair / Inspection ..........................................................46
7.7 Instructions for Packaging the Equipment ..............................................................46
8 Maintenance..............................................................................................................47
8.1 Maintenance Instructions...................................................................................... 47
8.2 Spare Parts and Accessories ................................................................................. 47
9 Index ........................................................................................................................ 48

Rev. 09/2020 5
Prior to use, read these assembly instructions carefully and familiarize yourself with the pro-
duct. Installation and start-up should not be carried out before reading and understanding this
document. Keep these assembly instructions readily available so that you can reference them as
needed.
1.1 What Is the Purpose of these Assembly Instructions?
These assembly instructions serve as an aid for the installation of the product and support the
technical staff with all maintenance tasks to be performed. Furthermore, these instructions are
aimed at preventing dangers to life and health of the user and third parties.
1.2 Who Are these Assembly Instructions Targeted to?
These assembly instructions provide a code of conduct for personnel tasked with the setup,
operation, maintenance, and repair of gas engines. A certain level of technical knowledge with
respect to the operation of gas engines and basic knowledge of the electronic components used
are necessary. Persons who are only authorized to operate the gas engine shall be trained by
the operating company and shall be expressly instructed concerning potential hazards.
1.3 What Symbols Are Used in the Assembly Instructions?
The following symbols are used in these instructions and must be observed:
Example
This symbol indicates examples, which point out necessary handling steps
and techniques. In addition, you receive additional information from the
examples, which will increase your knowledge.
Notice
This symbol indicates important notices for the user. Follow these. In addi-
tion, this symbol is used for overviews that give you a summary of the
necessary work steps.
Warning
This symbol indicates warnings for possible risks of property damage or
risks to health. Read these warning notices carefully and take the men-
tioned precautionary measures.
1 General Information

1 General Information
6 Rev. 09/2020
Danger
This symbol indicates warnings for danger to life, especially due to high
voltage. Read these warning notices carefully and take the mentioned
precautionary measures.
1.4 Which Abbreviations/Acronyms Are Used in the Assembly Instructions?
The following abbreviations/acronyms are used in the assembly instructions:
Abb. Term Description Explanation
CE Conformité
Européenne
Conformity with EU
directives
Mark based on EU legislation
for certain products in conjunc-
tion with product safety
CPR Counts Per Revolution Unit for the resolution of en-
coders
EMC Electromagnetic
Compatibility
Compatibility of electrical or
electronic equipment items
with their surroundings
ESD Electrostatic
Discharge
LNG Liquefied Natural Gas Natural gas liquefied by cooling
LPG Liquefied Petroleum
Gas
Petroleum gas liquefied by
cooling and compressing
RoHS Restriction of
Hazardous
Substances
TTL Transistor–Transistor
Logic
Circuit technology for logic
circuits

Rev. 09/2020 7
2.1 General Safety Instructions
MOTORTECH equipment is manufactured as state of the art and therefore safe and reliable to
operate. Nevertheless the equipment can cause risks or damage can occur, if the following
instructions are not complied with:
–The gas engine must only be operated by trained and authorized personnel.
–Observe all safety instructions of the system and all safety instructions of the system opera-
tor.
–Operate the equipment only within the parameters specified in the technical data.
–Use the equipment correctly and for its intended use only.
–Never apply force.
–For all work such as installation, conversion, adaptation, maintenance, and repair, all equip-
ment must be disconnected from the mains and secured against unintentional reactivation.
–Perform only such maintenance and repair work as is described in these assembly instruc-
tions, and follow the instructions given while working.
–Only use spare parts supplied by MOTORTECH for the maintenance of the device.
–Further work must only be performed by personnel authorized by MOTORTECH. Non-compli-
ance with the instructions will void any warranties for the proper function of the equipment
as well as the responsibility for the validity of the certifications.
–Safety devices must not be dismounted or disabled.
–Avoid all activities that can impair the function of the equipment.
–Operate the equipment only while it is in proper condition.
–Investigate all changes that occur during operation of the gas engine or electronic engine
control.
–Ensure compliance with all laws, directives, and regulations applicable to the operation of
your system, including such not expressly stated herein.
–If the system is not entirely tight and sealed, gas may escape and result in explosion hazard.
The inhalation of gas can also lead to death or severe health damages. Therefore, upon
completion of all assembly works, always check the system's tightness.
–Always ensure adequate ventilation of the engine compartment.
–Ensure a safe position at the gas engine.
–There is a risk of burning on hot surfaces. Allow the gas engine to cool down before starting
any work.
–Personal protective equipment (PPE), e.g. safety shoes and gloves, must be worn during all
work on the gas engine.
–Noise from the system can cause permanent or temporary damage to your hearing. Wear
suitable hearing protection at the system.
–Your behavior can reduce possible residual risks to a minimum. Observe responsible han-
dling of the gas engine and the gas-carrying system.
2 Safety Instructions

2 Safety Instructions
8 Rev. 09/2020
2.2 Electrostatic Discharge Hazards
Electronic equipment is sensitive to static electricity. To protect these components from damage
caused by static electricity, special precautions must be taken to minimize or prevent electro-
static discharge.
Observe these safety precautions while you work with the equipment or in its vicinity.
–Before performing maintenance or repair work, ensure that the static electricity inherent to
your body is discharged.
–Do not wear clothing made from synthetic materials to prevent static electricity from build-
ing up. Your clothing should therefore be made of cotton or cotton mix materials.
–Keep plastics such as vinyl and Styrofoam materials as far away from the equipment as
possible.
–Do not remove the circuit boards from the housing of the device.
2.3 Special Safety Instructions for the Device
Gas! Danger to life!
Leaking gas may cause death or serious health damage if inhaled. Upon
completion of all assembly works, always check the system's tightness.
When operating a VariFuel gas mixer, make sure that the gauge ports are
closed.
All works involving gas-carrying parts must be executed by trained person-
nel only.
Explosion hazard!
If the system is not entirely tight and sealed, gas may escape and result in
explosion hazard. Upon completion of all assembly works, always check the
system's tightness.
All works involving gas-carrying parts must be executed by trained person-
nel only.
Explosion hazard!
Do not disconnect any connectors while the system is live. If the system is
located in a hazardous area, there is a risk of explosion.

2 Safety Instructions
Rev. 09/2020 9
Operational safety!
All screws of the connectors must be adequately tightened.
Operational safety!
Contaminated gas can lead to blocking of the fuel ring and thus can cause
the gas engine to stop.
Examine the VariFuel2/2+ regularly for contamination as a part of the regu-
lar maintenance intervals customary for your system.
Use clean gas preferably.
Risk of destruction due to electrostatic discharge!
The VariStep3 stepper motor driver may only be installed by specialized
personnel who has been trained in handling ESD sensitive components and
with due regard to relevant ESD standards. It must be installed into a con-
trol cabinet, and it must comply with the ESD standard IEC 61340-5-1:2016.
Damage caused by electrostatic discharge is not covered by warranty.
Risk of burning!
The surfaces of the system may heat up to high temperatures.
Risk of destruction!
The stepper motor of the VariFuel is not suitable for carrying or lifting a gas
mixer. There is a danger that the stepper motor could break, and if the gas
mixer were to fall, it could result in injury or property damage.
Always carry or lift the gas mixer by its exterior housing.

2 Safety Instructions
10 Rev. 09/2020
Danger of interference with radio reception!
The device is not intended for use in residential areas and cannot ensure
adequate protection of radio reception in such environments.
2.4 Proper Transport
Transport the VariFuel2/2+ to the installation site unopened in its original carton.
2.5 Proper Storage
Clean the VariFuel2/2+ gas mixer before storing. Store the VariFuel2/2+ gas mixer in a dry and
clean place on even ground. For storage, place the VariFuel2/2+ upright on the flat support
surface on the underside of the device.
2.6 Proper Disposal
After the expiration of its service life, MOTORTECH equipment can be disposed of with other
commercial waste, or it may be returned to MOTORTECH. We will ensure its environmentally
friendly disposal.

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3.1 Functional Description
All graphics used in this section represent an example of a VariFuel2/2+ series 200-120.
Basic Design
The main task of the gas mixer is it to mix the fuel (gas) and the air so that an optimal combus-
tion is ensured within the gas engine. Here, the decisive optimization parameters are a high
degree of efficiency and low emissions that comply with relevant regulations.
In the VariFuel2/2+, gas and air are mixed based on the Venturi principle. Based on the suction
pressure of the engine, the air is sucked in through the air inlet into the Venturi nozzle. This
creates an underpressure at the most narrow place, which causes the gas to be sucked in
through the gas inlet . In this way, both the gas and the air are mixed and released at the
mixture outlet . The volume flow and thus the air/gas mixture can be adapted to the respective
engine by using different design sizes and different flow bodies in the Venturi nozzle.
3 Intended Use

3 Intended Use
12 Rev. 09/2020
Mixture Control
The fuel (gas) is guided into the nozzle using the adjustable rectangular openings in a fuel ring
, which are wedge-shaped in the VariFuel2+. The openings of the fuel ring are adjusted by a
stepper motor and a drive belt . The stepper motor of the VariFuel2/2+ is controlled by a
stepper motor driver. This can process the signals of a master control.
Connections
All VariFuel2/2+ gas mixers also have the following connections:
–An impulse line connection for connecting the air inlet to a balance or zero pressure regula-
tor
–A gauge port for measuring the gas pressure at the gas inlet by a pressure gauge

3 Intended Use
Rev. 09/2020 13
3.2 Applications
Danger of interference with radio reception!
The device is not intended for use in residential areas and cannot ensure
adequate protection of radio reception in such environments.
All VariFuel2/2+ air/gas mixers are designed for use with gas-powered Otto engines. The fol-
lowing substances are approved as fuels:
–Natural gas, biogas, landfill gas, sewage gas, wood gas, drilling-related gas, mine gas,
liquefied natural gas (LNG), liquefied petroleum gas (LPG)
–Additional special gases may be used upon approval (there may be restrictions in the case
of excessive moisture content or foreign materials in the gas such as tar)
Mixing the air and fuel with the VariFuel2/2+ must be done with the same pressure, therefore it
is necessary to use a balance or a zero pressure regulator within the gas train.
The VariFuel2/2+ can mix up to two gases with air. For lean gas applications (such as wood or
landfill gas) with a V-engine, it is possible to interconnect two VariFuel2/2+ to achieve the
desired mixing ratio.
If two VariFuel2/2+ gas mixers are to be used, two VariStep3 stepper motor drivers are required.
An additional splitter is not necessary.
Any use other than the one described in the assembly instructions shall be considered improper
use and will result in the voiding of all warranties.

3 Intended Use
14 Rev. 09/2020
System Overview (Example)
VariStep3 stepper motor driver Master control
VariFuel2/2+ gas mixer Flywheel
ITB throttle with integrated stepper motor Magnetic pickup
SC100 speed controller Engine
Impulse line
Air Air filter
Gas Ball valve
Gas filter
Double safety valve
Balance/Zero pressure regulator

Rev. 09/2020 15
4.1 Technical Data
4.1.1 Certifications
The VariFuel2/2+ air/gas mixers are certified as follows:
CE
Machinery Directive
–The VariFuel2/2+ air/gas mixers are partly completed machinery according to article 2g of
the EC Machinery Directive.
–The partly completed machine may only be commissioned once it has been established that
the machine into which the product mentioned above should be incorporated complies with
the provisions of the EC Machinery Directive.
–The following standards were considered:
–EN ISO 12100 – Safety of machinery - General principles for design - Risk assessment
and risk reduction
–EN 60204- 1 – Safety of machinery - Electrical equipment of machines - Part 1: General
requirements
EMC Directive
–EN 55011 – Industrial, scientific and medical equipment - Radio-frequency disturbance
characteristics - Limits and methods of measurement
–Group 1, Class A
–EN 60034- 1 – Rotating electrical machines - Part 1: Rating and performance
–EN 61000- 6- 2 – Electromagnetic compatibility (EMC) - Part 6- 2: Generic standards -
Immunity for industrial environments
The Declaration of Incorporation and the EU Declaration of Conformity of your VariFuel2/2+ are
enclosed with your product.
4 Product Description

4 Product Description
16 Rev. 09/2020
4.1.2 Mechanical Data
The devices of VariFuel2/2+ series have the following mechanical characteristics:
Feature Value
Dimensions See chapter Overview Drawings on page 19
Weight Series 100-60:
Series 140-80:
Series 200-120:
Series 250-150:
Series 300-190:
Series 350-225:
4.7 kg (10.4 lbs)
7.4 kg (16.3 lbs)
9.4 kg (20.8 lbs)
22.8 kg (50.3 lbs)
29.5 kg (65 lbs)
36.2 kg (79.8 lbs)
Shape of device See chapter Overview Drawings on page 19
Climatic environmental
conditions
VariFuel2: –10 °C to +80 °C (+14 °F to +176 °F)
VariFuel2+: –40 °C to +80 °C (–40 °F to +176 °F)
Max. humidity without condensation up to 2,000 m (6,561')
above sea level:
–85 % at +80 °C (+176 °F)
–60 % at –40 °C (–40 °F)
Air consumption min./max. Series 100-60:
Series 140-80:
Series 200-120:
Series 250-150:
Series 300-190:
Series 350-225:
100 m³/h to 650 m³/h
200 m³/h to 1,300 m³/h
500 m³/h to 3,200 m³/h
1,800 m³/h to 5,200 m³/h
3,400 m³/h to 8,500 m³/h
6,000 m³/h to 12,000 m³/h
Suitable for flow bodies with
min./max. diameter
Series 100-60:
Series 140-80:
Series 200-120:
Series 250-150:
Series 300-190:
Series 350-225:
23 mm to 45 mm
23 mm to 72.5 mm
23 mm to 105 mm
23 mm to 110 mm
35 mm to 140 mm
35 mm to 150 mm

4 Product Description
Rev. 09/2020 17
4.1.3 Warning Notices on the Device
Warning on Removable Gas Inlet Cover
Don't touch inside
Warning Symbol on Stepper Motor
Warning of hot surface
Warning Notice on Stepper Motor
CAUTION! Stepper motor rev. B only for use with VariStep stepper motor card.
Do not use stepper motor to lift or carry the device.

4 Product Description
18 Rev. 09/2020
4.1.4 Product Identification – Labeling on the Device
The necessary numbers for unique product identification are on the device:
Nameplate Air/Gas Mixer on Upper Part of Housing
Abb. Meaning
P/N Part number of the air/gas mixer
S/N Serial number of the air/gas mixer
The field Label Flow Body Size is reserved for the label that comes with the flow body. For further
information, refer to the section Install Flow Body on page 31.
Nameplate Stepper Motor
Abb. Meaning
P/N Part number of the stepper motor
PC Production code
REV. Revision of the stepper motor

4 Product Description
Rev. 09/2020 19
4.1.5 Overview Drawings
Components
The following drawing shows an example of a VariFuel2 series 200-120. The exact position of the
individual parts varies slightly with other series. A detailed layout can be found in the subse-
quent section Dimensions.
Pos. Description
Stepper motor
Gas connection (here closed with a cover)
Gauge port G1/8 for gas pressure measurement at the gas inlet by a pressure gauge
Impulse line connection (cutting-ring connection) G1/4 for connecting the air inlet to
a balance or zero pressure regulator
Flow body
Inspection window on the drive belt
Inspection window on the fuel ring
Gas connection

4 Product Description
20 Rev. 09/2020
Dimensions
Series 100-60
VariFuel2, VariFuel2+